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FAILED: patch "[PATCH] tracing: Have trace_marker use per-cpu data to read user" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 64cf7d058a005c5c31eb8a0b741f35dc12915d18 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101303-unsterile-observant-971f@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 64cf7d058a005c5c31eb8a0b741f35dc12915d18 Mon Sep 17 00:00:00 2001 From: Steven Rostedt <rostedt(a)goodmis.org> Date: Wed, 8 Oct 2025 12:45:10 -0400 Subject: [PATCH] tracing: Have trace_marker use per-cpu data to read user space It was reported that using __copy_from_user_inatomic() can actually schedule. Which is bad when preemption is disabled. Even though there's logic to check in_atomic() is set, but this is a nop when the kernel is configured with PREEMPT_NONE. This is due to page faulting and the code could schedule with preemption disabled. Link: https://lore.kernel.org/all/20250819105152.2766363-1-luogengkun@huaweicloud… The solution was to change the __copy_from_user_inatomic() to copy_from_user_nofault(). But then it was reported that this caused a regression in Android. There's several applications writing into trace_marker() in Android, but now instead of showing the expected data, it is showing: tracing_mark_write: <faulted> After reverting the conversion to copy_from_user_nofault(), Android was able to get the data again. Writes to the trace_marker is a way to efficiently and quickly enter data into the Linux tracing buffer. It takes no locks and was designed to be as non-intrusive as possible. This means it cannot allocate memory, and must use pre-allocated data. A method that is actively being worked on to have faultable system call tracepoints read user space data is to allocate per CPU buffers, and use them in the callback. The method uses a technique similar to seqcount. That is something like this: preempt_disable(); cpu = smp_processor_id(); buffer = this_cpu_ptr(&pre_allocated_cpu_buffers, cpu); do { cnt = nr_context_switches_cpu(cpu); migrate_disable(); preempt_enable(); ret = copy_from_user(buffer, ptr, size); preempt_disable(); migrate_enable(); } while (!ret && cnt != nr_context_switches_cpu(cpu)); if (!ret) ring_buffer_write(buffer); preempt_enable(); It's a little more involved than that, but the above is the basic logic. The idea is to acquire the current CPU buffer, disable migration, and then enable preemption. At this moment, it can safely use copy_from_user(). After reading the data from user space, it disables preemption again. It then checks to see if there was any new scheduling on this CPU. If there was, it must assume that the buffer was corrupted by another task. If there wasn't, then the buffer is still valid as only tasks in preemptable context can write to this buffer and only those that are running on the CPU. By using this method, where trace_marker open allocates the per CPU buffers, trace_marker writes can access user space and even fault it in, without having to allocate or take any locks of its own. Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Cc: Luo Gengkun <luogengkun(a)huaweicloud.com> Cc: Wattson CI <wattson-external(a)google.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Link: https://lore.kernel.org/20251008124510.6dba541a@gandalf.local.home Fixes: 3d62ab32df065 ("tracing: Fix tracing_marker may trigger page fault during preempt_disable") Reported-by: Runping Lai <runpinglai(a)google.com> Tested-by: Runping Lai <runpinglai(a)google.com> Closes: https://lore.kernel.org/linux-trace-kernel/20251007003417.3470979-2-runping… Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b3c94fbaf002..0fd582651293 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4791,12 +4791,6 @@ int tracing_single_release_file_tr(struct inode *inode, struct file *filp) return single_release(inode, filp); } -static int tracing_mark_open(struct inode *inode, struct file *filp) -{ - stream_open(inode, filp); - return tracing_open_generic_tr(inode, filp); -} - static int tracing_release(struct inode *inode, struct file *file) { struct trace_array *tr = inode->i_private; @@ -7163,7 +7157,7 @@ tracing_free_buffer_release(struct inode *inode, struct file *filp) #define TRACE_MARKER_MAX_SIZE 4096 -static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user *ubuf, +static ssize_t write_marker_to_buffer(struct trace_array *tr, const char *buf, size_t cnt, unsigned long ip) { struct ring_buffer_event *event; @@ -7173,20 +7167,11 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user int meta_size; ssize_t written; size_t size; - int len; - -/* Used in tracing_mark_raw_write() as well */ -#define FAULTED_STR "<faulted>" -#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */ meta_size = sizeof(*entry) + 2; /* add '\0' and possible '\n' */ again: size = cnt + meta_size; - /* If less than "<faulted>", then make sure we can still add that */ - if (cnt < FAULTED_SIZE) - size += FAULTED_SIZE - cnt; - buffer = tr->array_buffer.buffer; event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, tracing_gen_ctx()); @@ -7196,9 +7181,6 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user * make it smaller and try again. */ if (size > ring_buffer_max_event_size(buffer)) { - /* cnt < FAULTED size should never be bigger than max */ - if (WARN_ON_ONCE(cnt < FAULTED_SIZE)) - return -EBADF; cnt = ring_buffer_max_event_size(buffer) - meta_size; /* The above should only happen once */ if (WARN_ON_ONCE(cnt + meta_size == size)) @@ -7212,14 +7194,8 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user entry = ring_buffer_event_data(event); entry->ip = ip; - - len = copy_from_user_nofault(&entry->buf, ubuf, cnt); - if (len) { - memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE); - cnt = FAULTED_SIZE; - written = -EFAULT; - } else - written = cnt; + memcpy(&entry->buf, buf, cnt); + written = cnt; if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) { /* do not add \n before testing triggers, but add \0 */ @@ -7243,6 +7219,169 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user return written; } +struct trace_user_buf { + char *buf; +}; + +struct trace_user_buf_info { + struct trace_user_buf __percpu *tbuf; + int ref; +}; + + +static DEFINE_MUTEX(trace_user_buffer_mutex); +static struct trace_user_buf_info *trace_user_buffer; + +static void trace_user_fault_buffer_free(struct trace_user_buf_info *tinfo) +{ + char *buf; + int cpu; + + for_each_possible_cpu(cpu) { + buf = per_cpu_ptr(tinfo->tbuf, cpu)->buf; + kfree(buf); + } + free_percpu(tinfo->tbuf); + kfree(tinfo); +} + +static int trace_user_fault_buffer_enable(void) +{ + struct trace_user_buf_info *tinfo; + char *buf; + int cpu; + + guard(mutex)(&trace_user_buffer_mutex); + + if (trace_user_buffer) { + trace_user_buffer->ref++; + return 0; + } + + tinfo = kmalloc(sizeof(*tinfo), GFP_KERNEL); + if (!tinfo) + return -ENOMEM; + + tinfo->tbuf = alloc_percpu(struct trace_user_buf); + if (!tinfo->tbuf) { + kfree(tinfo); + return -ENOMEM; + } + + tinfo->ref = 1; + + /* Clear each buffer in case of error */ + for_each_possible_cpu(cpu) { + per_cpu_ptr(tinfo->tbuf, cpu)->buf = NULL; + } + + for_each_possible_cpu(cpu) { + buf = kmalloc_node(TRACE_MARKER_MAX_SIZE, GFP_KERNEL, + cpu_to_node(cpu)); + if (!buf) { + trace_user_fault_buffer_free(tinfo); + return -ENOMEM; + } + per_cpu_ptr(tinfo->tbuf, cpu)->buf = buf; + } + + trace_user_buffer = tinfo; + + return 0; +} + +static void trace_user_fault_buffer_disable(void) +{ + struct trace_user_buf_info *tinfo; + + guard(mutex)(&trace_user_buffer_mutex); + + tinfo = trace_user_buffer; + + if (WARN_ON_ONCE(!tinfo)) + return; + + if (--tinfo->ref) + return; + + trace_user_fault_buffer_free(tinfo); + trace_user_buffer = NULL; +} + +/* Must be called with preemption disabled */ +static char *trace_user_fault_read(struct trace_user_buf_info *tinfo, + const char __user *ptr, size_t size, + size_t *read_size) +{ + int cpu = smp_processor_id(); + char *buffer = per_cpu_ptr(tinfo->tbuf, cpu)->buf; + unsigned int cnt; + int trys = 0; + int ret; + + if (size > TRACE_MARKER_MAX_SIZE) + size = TRACE_MARKER_MAX_SIZE; + *read_size = 0; + + /* + * This acts similar to a seqcount. The per CPU context switches are + * recorded, migration is disabled and preemption is enabled. The + * read of the user space memory is copied into the per CPU buffer. + * Preemption is disabled again, and if the per CPU context switches count + * is still the same, it means the buffer has not been corrupted. + * If the count is different, it is assumed the buffer is corrupted + * and reading must be tried again. + */ + + do { + /* + * If for some reason, copy_from_user() always causes a context + * switch, this would then cause an infinite loop. + * If this task is preempted by another user space task, it + * will cause this task to try again. But just in case something + * changes where the copying from user space causes another task + * to run, prevent this from going into an infinite loop. + * 100 tries should be plenty. + */ + if (WARN_ONCE(trys++ > 100, "Error: Too many tries to read user space")) + return NULL; + + /* Read the current CPU context switch counter */ + cnt = nr_context_switches_cpu(cpu); + + /* + * Preemption is going to be enabled, but this task must + * remain on this CPU. + */ + migrate_disable(); + + /* + * Now preemption is being enabed and another task can come in + * and use the same buffer and corrupt our data. + */ + preempt_enable_notrace(); + + ret = __copy_from_user(buffer, ptr, size); + + preempt_disable_notrace(); + migrate_enable(); + + /* if it faulted, no need to test if the buffer was corrupted */ + if (ret) + return NULL; + + /* + * Preemption is disabled again, now check the per CPU context + * switch counter. If it doesn't match, then another user space + * process may have schedule in and corrupted our buffer. In that + * case the copying must be retried. + */ + } while (nr_context_switches_cpu(cpu) != cnt); + + *read_size = size; + return buffer; +} + static ssize_t tracing_mark_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *fpos) @@ -7250,6 +7389,8 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, struct trace_array *tr = filp->private_data; ssize_t written = -ENODEV; unsigned long ip; + size_t size; + char *buf; if (tracing_disabled) return -EINVAL; @@ -7263,6 +7404,16 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, if (cnt > TRACE_MARKER_MAX_SIZE) cnt = TRACE_MARKER_MAX_SIZE; + /* Must have preemption disabled while having access to the buffer */ + guard(preempt_notrace)(); + + buf = trace_user_fault_read(trace_user_buffer, ubuf, cnt, &size); + if (!buf) + return -EFAULT; + + if (cnt > size) + cnt = size; + /* The selftests expect this function to be the IP address */ ip = _THIS_IP_; @@ -7270,32 +7421,27 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, if (tr == &global_trace) { guard(rcu)(); list_for_each_entry_rcu(tr, &marker_copies, marker_list) { - written = write_marker_to_buffer(tr, ubuf, cnt, ip); + written = write_marker_to_buffer(tr, buf, cnt, ip); if (written < 0) break; } } else { - written = write_marker_to_buffer(tr, ubuf, cnt, ip); + written = write_marker_to_buffer(tr, buf, cnt, ip); } return written; } static ssize_t write_raw_marker_to_buffer(struct trace_array *tr, - const char __user *ubuf, size_t cnt) + const char *buf, size_t cnt) { struct ring_buffer_event *event; struct trace_buffer *buffer; struct raw_data_entry *entry; ssize_t written; - int size; - int len; - -#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int)) + size_t size; size = sizeof(*entry) + cnt; - if (cnt < FAULT_SIZE_ID) - size += FAULT_SIZE_ID - cnt; buffer = tr->array_buffer.buffer; @@ -7309,14 +7455,8 @@ static ssize_t write_raw_marker_to_buffer(struct trace_array *tr, return -EBADF; entry = ring_buffer_event_data(event); - - len = copy_from_user_nofault(&entry->id, ubuf, cnt); - if (len) { - entry->id = -1; - memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE); - written = -EFAULT; - } else - written = cnt; + memcpy(&entry->id, buf, cnt); + written = cnt; __buffer_unlock_commit(buffer, event); @@ -7329,8 +7469,8 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf, { struct trace_array *tr = filp->private_data; ssize_t written = -ENODEV; - -#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int)) + size_t size; + char *buf; if (tracing_disabled) return -EINVAL; @@ -7342,6 +7482,17 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf, if (cnt < sizeof(unsigned int)) return -EINVAL; + /* Must have preemption disabled while having access to the buffer */ + guard(preempt_notrace)(); + + buf = trace_user_fault_read(trace_user_buffer, ubuf, cnt, &size); + if (!buf) + return -EFAULT; + + /* raw write is all or nothing */ + if (cnt > size) + return -EINVAL; + /* The global trace_marker_raw can go to multiple instances */ if (tr == &global_trace) { guard(rcu)(); @@ -7357,6 +7508,27 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf, return written; } +static int tracing_mark_open(struct inode *inode, struct file *filp) +{ + int ret; + + ret = trace_user_fault_buffer_enable(); + if (ret < 0) + return ret; + + stream_open(inode, filp); + ret = tracing_open_generic_tr(inode, filp); + if (ret < 0) + trace_user_fault_buffer_disable(); + return ret; +} + +static int tracing_mark_release(struct inode *inode, struct file *file) +{ + trace_user_fault_buffer_disable(); + return tracing_release_generic_tr(inode, file); +} + static int tracing_clock_show(struct seq_file *m, void *v) { struct trace_array *tr = m->private; @@ -7764,13 +7936,13 @@ static const struct file_operations tracing_free_buffer_fops = { static const struct file_operations tracing_mark_fops = { .open = tracing_mark_open, .write = tracing_mark_write, - .release = tracing_release_generic_tr, + .release = tracing_mark_release, }; static const struct file_operations tracing_mark_raw_fops = { .open = tracing_mark_open, .write = tracing_mark_raw_write, - .release = tracing_release_generic_tr, + .release = tracing_mark_release, }; static const struct file_operations trace_clock_fops = {

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FAILED: patch "[PATCH] tracing: Have trace_marker use per-cpu data to read user" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 64cf7d058a005c5c31eb8a0b741f35dc12915d18 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101300-unburned-stage-ee62@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 64cf7d058a005c5c31eb8a0b741f35dc12915d18 Mon Sep 17 00:00:00 2001 From: Steven Rostedt <rostedt(a)goodmis.org> Date: Wed, 8 Oct 2025 12:45:10 -0400 Subject: [PATCH] tracing: Have trace_marker use per-cpu data to read user space It was reported that using __copy_from_user_inatomic() can actually schedule. Which is bad when preemption is disabled. Even though there's logic to check in_atomic() is set, but this is a nop when the kernel is configured with PREEMPT_NONE. This is due to page faulting and the code could schedule with preemption disabled. Link: https://lore.kernel.org/all/20250819105152.2766363-1-luogengkun@huaweicloud… The solution was to change the __copy_from_user_inatomic() to copy_from_user_nofault(). But then it was reported that this caused a regression in Android. There's several applications writing into trace_marker() in Android, but now instead of showing the expected data, it is showing: tracing_mark_write: <faulted> After reverting the conversion to copy_from_user_nofault(), Android was able to get the data again. Writes to the trace_marker is a way to efficiently and quickly enter data into the Linux tracing buffer. It takes no locks and was designed to be as non-intrusive as possible. This means it cannot allocate memory, and must use pre-allocated data. A method that is actively being worked on to have faultable system call tracepoints read user space data is to allocate per CPU buffers, and use them in the callback. The method uses a technique similar to seqcount. That is something like this: preempt_disable(); cpu = smp_processor_id(); buffer = this_cpu_ptr(&pre_allocated_cpu_buffers, cpu); do { cnt = nr_context_switches_cpu(cpu); migrate_disable(); preempt_enable(); ret = copy_from_user(buffer, ptr, size); preempt_disable(); migrate_enable(); } while (!ret && cnt != nr_context_switches_cpu(cpu)); if (!ret) ring_buffer_write(buffer); preempt_enable(); It's a little more involved than that, but the above is the basic logic. The idea is to acquire the current CPU buffer, disable migration, and then enable preemption. At this moment, it can safely use copy_from_user(). After reading the data from user space, it disables preemption again. It then checks to see if there was any new scheduling on this CPU. If there was, it must assume that the buffer was corrupted by another task. If there wasn't, then the buffer is still valid as only tasks in preemptable context can write to this buffer and only those that are running on the CPU. By using this method, where trace_marker open allocates the per CPU buffers, trace_marker writes can access user space and even fault it in, without having to allocate or take any locks of its own. Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Cc: Luo Gengkun <luogengkun(a)huaweicloud.com> Cc: Wattson CI <wattson-external(a)google.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Link: https://lore.kernel.org/20251008124510.6dba541a@gandalf.local.home Fixes: 3d62ab32df065 ("tracing: Fix tracing_marker may trigger page fault during preempt_disable") Reported-by: Runping Lai <runpinglai(a)google.com> Tested-by: Runping Lai <runpinglai(a)google.com> Closes: https://lore.kernel.org/linux-trace-kernel/20251007003417.3470979-2-runping… Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b3c94fbaf002..0fd582651293 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4791,12 +4791,6 @@ int tracing_single_release_file_tr(struct inode *inode, struct file *filp) return single_release(inode, filp); } -static int tracing_mark_open(struct inode *inode, struct file *filp) -{ - stream_open(inode, filp); - return tracing_open_generic_tr(inode, filp); -} - static int tracing_release(struct inode *inode, struct file *file) { struct trace_array *tr = inode->i_private; @@ -7163,7 +7157,7 @@ tracing_free_buffer_release(struct inode *inode, struct file *filp) #define TRACE_MARKER_MAX_SIZE 4096 -static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user *ubuf, +static ssize_t write_marker_to_buffer(struct trace_array *tr, const char *buf, size_t cnt, unsigned long ip) { struct ring_buffer_event *event; @@ -7173,20 +7167,11 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user int meta_size; ssize_t written; size_t size; - int len; - -/* Used in tracing_mark_raw_write() as well */ -#define FAULTED_STR "<faulted>" -#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */ meta_size = sizeof(*entry) + 2; /* add '\0' and possible '\n' */ again: size = cnt + meta_size; - /* If less than "<faulted>", then make sure we can still add that */ - if (cnt < FAULTED_SIZE) - size += FAULTED_SIZE - cnt; - buffer = tr->array_buffer.buffer; event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, tracing_gen_ctx()); @@ -7196,9 +7181,6 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user * make it smaller and try again. */ if (size > ring_buffer_max_event_size(buffer)) { - /* cnt < FAULTED size should never be bigger than max */ - if (WARN_ON_ONCE(cnt < FAULTED_SIZE)) - return -EBADF; cnt = ring_buffer_max_event_size(buffer) - meta_size; /* The above should only happen once */ if (WARN_ON_ONCE(cnt + meta_size == size)) @@ -7212,14 +7194,8 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user entry = ring_buffer_event_data(event); entry->ip = ip; - - len = copy_from_user_nofault(&entry->buf, ubuf, cnt); - if (len) { - memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE); - cnt = FAULTED_SIZE; - written = -EFAULT; - } else - written = cnt; + memcpy(&entry->buf, buf, cnt); + written = cnt; if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) { /* do not add \n before testing triggers, but add \0 */ @@ -7243,6 +7219,169 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user return written; } +struct trace_user_buf { + char *buf; +}; + +struct trace_user_buf_info { + struct trace_user_buf __percpu *tbuf; + int ref; +}; + + +static DEFINE_MUTEX(trace_user_buffer_mutex); +static struct trace_user_buf_info *trace_user_buffer; + +static void trace_user_fault_buffer_free(struct trace_user_buf_info *tinfo) +{ + char *buf; + int cpu; + + for_each_possible_cpu(cpu) { + buf = per_cpu_ptr(tinfo->tbuf, cpu)->buf; + kfree(buf); + } + free_percpu(tinfo->tbuf); + kfree(tinfo); +} + +static int trace_user_fault_buffer_enable(void) +{ + struct trace_user_buf_info *tinfo; + char *buf; + int cpu; + + guard(mutex)(&trace_user_buffer_mutex); + + if (trace_user_buffer) { + trace_user_buffer->ref++; + return 0; + } + + tinfo = kmalloc(sizeof(*tinfo), GFP_KERNEL); + if (!tinfo) + return -ENOMEM; + + tinfo->tbuf = alloc_percpu(struct trace_user_buf); + if (!tinfo->tbuf) { + kfree(tinfo); + return -ENOMEM; + } + + tinfo->ref = 1; + + /* Clear each buffer in case of error */ + for_each_possible_cpu(cpu) { + per_cpu_ptr(tinfo->tbuf, cpu)->buf = NULL; + } + + for_each_possible_cpu(cpu) { + buf = kmalloc_node(TRACE_MARKER_MAX_SIZE, GFP_KERNEL, + cpu_to_node(cpu)); + if (!buf) { + trace_user_fault_buffer_free(tinfo); + return -ENOMEM; + } + per_cpu_ptr(tinfo->tbuf, cpu)->buf = buf; + } + + trace_user_buffer = tinfo; + + return 0; +} + +static void trace_user_fault_buffer_disable(void) +{ + struct trace_user_buf_info *tinfo; + + guard(mutex)(&trace_user_buffer_mutex); + + tinfo = trace_user_buffer; + + if (WARN_ON_ONCE(!tinfo)) + return; + + if (--tinfo->ref) + return; + + trace_user_fault_buffer_free(tinfo); + trace_user_buffer = NULL; +} + +/* Must be called with preemption disabled */ +static char *trace_user_fault_read(struct trace_user_buf_info *tinfo, + const char __user *ptr, size_t size, + size_t *read_size) +{ + int cpu = smp_processor_id(); + char *buffer = per_cpu_ptr(tinfo->tbuf, cpu)->buf; + unsigned int cnt; + int trys = 0; + int ret; + + if (size > TRACE_MARKER_MAX_SIZE) + size = TRACE_MARKER_MAX_SIZE; + *read_size = 0; + + /* + * This acts similar to a seqcount. The per CPU context switches are + * recorded, migration is disabled and preemption is enabled. The + * read of the user space memory is copied into the per CPU buffer. + * Preemption is disabled again, and if the per CPU context switches count + * is still the same, it means the buffer has not been corrupted. + * If the count is different, it is assumed the buffer is corrupted + * and reading must be tried again. + */ + + do { + /* + * If for some reason, copy_from_user() always causes a context + * switch, this would then cause an infinite loop. + * If this task is preempted by another user space task, it + * will cause this task to try again. But just in case something + * changes where the copying from user space causes another task + * to run, prevent this from going into an infinite loop. + * 100 tries should be plenty. + */ + if (WARN_ONCE(trys++ > 100, "Error: Too many tries to read user space")) + return NULL; + + /* Read the current CPU context switch counter */ + cnt = nr_context_switches_cpu(cpu); + + /* + * Preemption is going to be enabled, but this task must + * remain on this CPU. + */ + migrate_disable(); + + /* + * Now preemption is being enabed and another task can come in + * and use the same buffer and corrupt our data. + */ + preempt_enable_notrace(); + + ret = __copy_from_user(buffer, ptr, size); + + preempt_disable_notrace(); + migrate_enable(); + + /* if it faulted, no need to test if the buffer was corrupted */ + if (ret) + return NULL; + + /* + * Preemption is disabled again, now check the per CPU context + * switch counter. If it doesn't match, then another user space + * process may have schedule in and corrupted our buffer. In that + * case the copying must be retried. + */ + } while (nr_context_switches_cpu(cpu) != cnt); + + *read_size = size; + return buffer; +} + static ssize_t tracing_mark_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *fpos) @@ -7250,6 +7389,8 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, struct trace_array *tr = filp->private_data; ssize_t written = -ENODEV; unsigned long ip; + size_t size; + char *buf; if (tracing_disabled) return -EINVAL; @@ -7263,6 +7404,16 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, if (cnt > TRACE_MARKER_MAX_SIZE) cnt = TRACE_MARKER_MAX_SIZE; + /* Must have preemption disabled while having access to the buffer */ + guard(preempt_notrace)(); + + buf = trace_user_fault_read(trace_user_buffer, ubuf, cnt, &size); + if (!buf) + return -EFAULT; + + if (cnt > size) + cnt = size; + /* The selftests expect this function to be the IP address */ ip = _THIS_IP_; @@ -7270,32 +7421,27 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, if (tr == &global_trace) { guard(rcu)(); list_for_each_entry_rcu(tr, &marker_copies, marker_list) { - written = write_marker_to_buffer(tr, ubuf, cnt, ip); + written = write_marker_to_buffer(tr, buf, cnt, ip); if (written < 0) break; } } else { - written = write_marker_to_buffer(tr, ubuf, cnt, ip); + written = write_marker_to_buffer(tr, buf, cnt, ip); } return written; } static ssize_t write_raw_marker_to_buffer(struct trace_array *tr, - const char __user *ubuf, size_t cnt) + const char *buf, size_t cnt) { struct ring_buffer_event *event; struct trace_buffer *buffer; struct raw_data_entry *entry; ssize_t written; - int size; - int len; - -#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int)) + size_t size; size = sizeof(*entry) + cnt; - if (cnt < FAULT_SIZE_ID) - size += FAULT_SIZE_ID - cnt; buffer = tr->array_buffer.buffer; @@ -7309,14 +7455,8 @@ static ssize_t write_raw_marker_to_buffer(struct trace_array *tr, return -EBADF; entry = ring_buffer_event_data(event); - - len = copy_from_user_nofault(&entry->id, ubuf, cnt); - if (len) { - entry->id = -1; - memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE); - written = -EFAULT; - } else - written = cnt; + memcpy(&entry->id, buf, cnt); + written = cnt; __buffer_unlock_commit(buffer, event); @@ -7329,8 +7469,8 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf, { struct trace_array *tr = filp->private_data; ssize_t written = -ENODEV; - -#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int)) + size_t size; + char *buf; if (tracing_disabled) return -EINVAL; @@ -7342,6 +7482,17 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf, if (cnt < sizeof(unsigned int)) return -EINVAL; + /* Must have preemption disabled while having access to the buffer */ + guard(preempt_notrace)(); + + buf = trace_user_fault_read(trace_user_buffer, ubuf, cnt, &size); + if (!buf) + return -EFAULT; + + /* raw write is all or nothing */ + if (cnt > size) + return -EINVAL; + /* The global trace_marker_raw can go to multiple instances */ if (tr == &global_trace) { guard(rcu)(); @@ -7357,6 +7508,27 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf, return written; } +static int tracing_mark_open(struct inode *inode, struct file *filp) +{ + int ret; + + ret = trace_user_fault_buffer_enable(); + if (ret < 0) + return ret; + + stream_open(inode, filp); + ret = tracing_open_generic_tr(inode, filp); + if (ret < 0) + trace_user_fault_buffer_disable(); + return ret; +} + +static int tracing_mark_release(struct inode *inode, struct file *file) +{ + trace_user_fault_buffer_disable(); + return tracing_release_generic_tr(inode, file); +} + static int tracing_clock_show(struct seq_file *m, void *v) { struct trace_array *tr = m->private; @@ -7764,13 +7936,13 @@ static const struct file_operations tracing_free_buffer_fops = { static const struct file_operations tracing_mark_fops = { .open = tracing_mark_open, .write = tracing_mark_write, - .release = tracing_release_generic_tr, + .release = tracing_mark_release, }; static const struct file_operations tracing_mark_raw_fops = { .open = tracing_mark_open, .write = tracing_mark_raw_write, - .release = tracing_release_generic_tr, + .release = tracing_mark_release, }; static const struct file_operations trace_clock_fops = {

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FAILED: patch "[PATCH] tracing: Have trace_marker use per-cpu data to read user" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 64cf7d058a005c5c31eb8a0b741f35dc12915d18 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101357-tremble-silenced-1049@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 64cf7d058a005c5c31eb8a0b741f35dc12915d18 Mon Sep 17 00:00:00 2001 From: Steven Rostedt <rostedt(a)goodmis.org> Date: Wed, 8 Oct 2025 12:45:10 -0400 Subject: [PATCH] tracing: Have trace_marker use per-cpu data to read user space It was reported that using __copy_from_user_inatomic() can actually schedule. Which is bad when preemption is disabled. Even though there's logic to check in_atomic() is set, but this is a nop when the kernel is configured with PREEMPT_NONE. This is due to page faulting and the code could schedule with preemption disabled. Link: https://lore.kernel.org/all/20250819105152.2766363-1-luogengkun@huaweicloud… The solution was to change the __copy_from_user_inatomic() to copy_from_user_nofault(). But then it was reported that this caused a regression in Android. There's several applications writing into trace_marker() in Android, but now instead of showing the expected data, it is showing: tracing_mark_write: <faulted> After reverting the conversion to copy_from_user_nofault(), Android was able to get the data again. Writes to the trace_marker is a way to efficiently and quickly enter data into the Linux tracing buffer. It takes no locks and was designed to be as non-intrusive as possible. This means it cannot allocate memory, and must use pre-allocated data. A method that is actively being worked on to have faultable system call tracepoints read user space data is to allocate per CPU buffers, and use them in the callback. The method uses a technique similar to seqcount. That is something like this: preempt_disable(); cpu = smp_processor_id(); buffer = this_cpu_ptr(&pre_allocated_cpu_buffers, cpu); do { cnt = nr_context_switches_cpu(cpu); migrate_disable(); preempt_enable(); ret = copy_from_user(buffer, ptr, size); preempt_disable(); migrate_enable(); } while (!ret && cnt != nr_context_switches_cpu(cpu)); if (!ret) ring_buffer_write(buffer); preempt_enable(); It's a little more involved than that, but the above is the basic logic. The idea is to acquire the current CPU buffer, disable migration, and then enable preemption. At this moment, it can safely use copy_from_user(). After reading the data from user space, it disables preemption again. It then checks to see if there was any new scheduling on this CPU. If there was, it must assume that the buffer was corrupted by another task. If there wasn't, then the buffer is still valid as only tasks in preemptable context can write to this buffer and only those that are running on the CPU. By using this method, where trace_marker open allocates the per CPU buffers, trace_marker writes can access user space and even fault it in, without having to allocate or take any locks of its own. Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Cc: Luo Gengkun <luogengkun(a)huaweicloud.com> Cc: Wattson CI <wattson-external(a)google.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Link: https://lore.kernel.org/20251008124510.6dba541a@gandalf.local.home Fixes: 3d62ab32df065 ("tracing: Fix tracing_marker may trigger page fault during preempt_disable") Reported-by: Runping Lai <runpinglai(a)google.com> Tested-by: Runping Lai <runpinglai(a)google.com> Closes: https://lore.kernel.org/linux-trace-kernel/20251007003417.3470979-2-runping… Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b3c94fbaf002..0fd582651293 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4791,12 +4791,6 @@ int tracing_single_release_file_tr(struct inode *inode, struct file *filp) return single_release(inode, filp); } -static int tracing_mark_open(struct inode *inode, struct file *filp) -{ - stream_open(inode, filp); - return tracing_open_generic_tr(inode, filp); -} - static int tracing_release(struct inode *inode, struct file *file) { struct trace_array *tr = inode->i_private; @@ -7163,7 +7157,7 @@ tracing_free_buffer_release(struct inode *inode, struct file *filp) #define TRACE_MARKER_MAX_SIZE 4096 -static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user *ubuf, +static ssize_t write_marker_to_buffer(struct trace_array *tr, const char *buf, size_t cnt, unsigned long ip) { struct ring_buffer_event *event; @@ -7173,20 +7167,11 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user int meta_size; ssize_t written; size_t size; - int len; - -/* Used in tracing_mark_raw_write() as well */ -#define FAULTED_STR "<faulted>" -#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */ meta_size = sizeof(*entry) + 2; /* add '\0' and possible '\n' */ again: size = cnt + meta_size; - /* If less than "<faulted>", then make sure we can still add that */ - if (cnt < FAULTED_SIZE) - size += FAULTED_SIZE - cnt; - buffer = tr->array_buffer.buffer; event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, tracing_gen_ctx()); @@ -7196,9 +7181,6 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user * make it smaller and try again. */ if (size > ring_buffer_max_event_size(buffer)) { - /* cnt < FAULTED size should never be bigger than max */ - if (WARN_ON_ONCE(cnt < FAULTED_SIZE)) - return -EBADF; cnt = ring_buffer_max_event_size(buffer) - meta_size; /* The above should only happen once */ if (WARN_ON_ONCE(cnt + meta_size == size)) @@ -7212,14 +7194,8 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user entry = ring_buffer_event_data(event); entry->ip = ip; - - len = copy_from_user_nofault(&entry->buf, ubuf, cnt); - if (len) { - memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE); - cnt = FAULTED_SIZE; - written = -EFAULT; - } else - written = cnt; + memcpy(&entry->buf, buf, cnt); + written = cnt; if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) { /* do not add \n before testing triggers, but add \0 */ @@ -7243,6 +7219,169 @@ static ssize_t write_marker_to_buffer(struct trace_array *tr, const char __user return written; } +struct trace_user_buf { + char *buf; +}; + +struct trace_user_buf_info { + struct trace_user_buf __percpu *tbuf; + int ref; +}; + + +static DEFINE_MUTEX(trace_user_buffer_mutex); +static struct trace_user_buf_info *trace_user_buffer; + +static void trace_user_fault_buffer_free(struct trace_user_buf_info *tinfo) +{ + char *buf; + int cpu; + + for_each_possible_cpu(cpu) { + buf = per_cpu_ptr(tinfo->tbuf, cpu)->buf; + kfree(buf); + } + free_percpu(tinfo->tbuf); + kfree(tinfo); +} + +static int trace_user_fault_buffer_enable(void) +{ + struct trace_user_buf_info *tinfo; + char *buf; + int cpu; + + guard(mutex)(&trace_user_buffer_mutex); + + if (trace_user_buffer) { + trace_user_buffer->ref++; + return 0; + } + + tinfo = kmalloc(sizeof(*tinfo), GFP_KERNEL); + if (!tinfo) + return -ENOMEM; + + tinfo->tbuf = alloc_percpu(struct trace_user_buf); + if (!tinfo->tbuf) { + kfree(tinfo); + return -ENOMEM; + } + + tinfo->ref = 1; + + /* Clear each buffer in case of error */ + for_each_possible_cpu(cpu) { + per_cpu_ptr(tinfo->tbuf, cpu)->buf = NULL; + } + + for_each_possible_cpu(cpu) { + buf = kmalloc_node(TRACE_MARKER_MAX_SIZE, GFP_KERNEL, + cpu_to_node(cpu)); + if (!buf) { + trace_user_fault_buffer_free(tinfo); + return -ENOMEM; + } + per_cpu_ptr(tinfo->tbuf, cpu)->buf = buf; + } + + trace_user_buffer = tinfo; + + return 0; +} + +static void trace_user_fault_buffer_disable(void) +{ + struct trace_user_buf_info *tinfo; + + guard(mutex)(&trace_user_buffer_mutex); + + tinfo = trace_user_buffer; + + if (WARN_ON_ONCE(!tinfo)) + return; + + if (--tinfo->ref) + return; + + trace_user_fault_buffer_free(tinfo); + trace_user_buffer = NULL; +} + +/* Must be called with preemption disabled */ +static char *trace_user_fault_read(struct trace_user_buf_info *tinfo, + const char __user *ptr, size_t size, + size_t *read_size) +{ + int cpu = smp_processor_id(); + char *buffer = per_cpu_ptr(tinfo->tbuf, cpu)->buf; + unsigned int cnt; + int trys = 0; + int ret; + + if (size > TRACE_MARKER_MAX_SIZE) + size = TRACE_MARKER_MAX_SIZE; + *read_size = 0; + + /* + * This acts similar to a seqcount. The per CPU context switches are + * recorded, migration is disabled and preemption is enabled. The + * read of the user space memory is copied into the per CPU buffer. + * Preemption is disabled again, and if the per CPU context switches count + * is still the same, it means the buffer has not been corrupted. + * If the count is different, it is assumed the buffer is corrupted + * and reading must be tried again. + */ + + do { + /* + * If for some reason, copy_from_user() always causes a context + * switch, this would then cause an infinite loop. + * If this task is preempted by another user space task, it + * will cause this task to try again. But just in case something + * changes where the copying from user space causes another task + * to run, prevent this from going into an infinite loop. + * 100 tries should be plenty. + */ + if (WARN_ONCE(trys++ > 100, "Error: Too many tries to read user space")) + return NULL; + + /* Read the current CPU context switch counter */ + cnt = nr_context_switches_cpu(cpu); + + /* + * Preemption is going to be enabled, but this task must + * remain on this CPU. + */ + migrate_disable(); + + /* + * Now preemption is being enabed and another task can come in + * and use the same buffer and corrupt our data. + */ + preempt_enable_notrace(); + + ret = __copy_from_user(buffer, ptr, size); + + preempt_disable_notrace(); + migrate_enable(); + + /* if it faulted, no need to test if the buffer was corrupted */ + if (ret) + return NULL; + + /* + * Preemption is disabled again, now check the per CPU context + * switch counter. If it doesn't match, then another user space + * process may have schedule in and corrupted our buffer. In that + * case the copying must be retried. + */ + } while (nr_context_switches_cpu(cpu) != cnt); + + *read_size = size; + return buffer; +} + static ssize_t tracing_mark_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *fpos) @@ -7250,6 +7389,8 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, struct trace_array *tr = filp->private_data; ssize_t written = -ENODEV; unsigned long ip; + size_t size; + char *buf; if (tracing_disabled) return -EINVAL; @@ -7263,6 +7404,16 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, if (cnt > TRACE_MARKER_MAX_SIZE) cnt = TRACE_MARKER_MAX_SIZE; + /* Must have preemption disabled while having access to the buffer */ + guard(preempt_notrace)(); + + buf = trace_user_fault_read(trace_user_buffer, ubuf, cnt, &size); + if (!buf) + return -EFAULT; + + if (cnt > size) + cnt = size; + /* The selftests expect this function to be the IP address */ ip = _THIS_IP_; @@ -7270,32 +7421,27 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, if (tr == &global_trace) { guard(rcu)(); list_for_each_entry_rcu(tr, &marker_copies, marker_list) { - written = write_marker_to_buffer(tr, ubuf, cnt, ip); + written = write_marker_to_buffer(tr, buf, cnt, ip); if (written < 0) break; } } else { - written = write_marker_to_buffer(tr, ubuf, cnt, ip); + written = write_marker_to_buffer(tr, buf, cnt, ip); } return written; } static ssize_t write_raw_marker_to_buffer(struct trace_array *tr, - const char __user *ubuf, size_t cnt) + const char *buf, size_t cnt) { struct ring_buffer_event *event; struct trace_buffer *buffer; struct raw_data_entry *entry; ssize_t written; - int size; - int len; - -#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int)) + size_t size; size = sizeof(*entry) + cnt; - if (cnt < FAULT_SIZE_ID) - size += FAULT_SIZE_ID - cnt; buffer = tr->array_buffer.buffer; @@ -7309,14 +7455,8 @@ static ssize_t write_raw_marker_to_buffer(struct trace_array *tr, return -EBADF; entry = ring_buffer_event_data(event); - - len = copy_from_user_nofault(&entry->id, ubuf, cnt); - if (len) { - entry->id = -1; - memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE); - written = -EFAULT; - } else - written = cnt; + memcpy(&entry->id, buf, cnt); + written = cnt; __buffer_unlock_commit(buffer, event); @@ -7329,8 +7469,8 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf, { struct trace_array *tr = filp->private_data; ssize_t written = -ENODEV; - -#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int)) + size_t size; + char *buf; if (tracing_disabled) return -EINVAL; @@ -7342,6 +7482,17 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf, if (cnt < sizeof(unsigned int)) return -EINVAL; + /* Must have preemption disabled while having access to the buffer */ + guard(preempt_notrace)(); + + buf = trace_user_fault_read(trace_user_buffer, ubuf, cnt, &size); + if (!buf) + return -EFAULT; + + /* raw write is all or nothing */ + if (cnt > size) + return -EINVAL; + /* The global trace_marker_raw can go to multiple instances */ if (tr == &global_trace) { guard(rcu)(); @@ -7357,6 +7508,27 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf, return written; } +static int tracing_mark_open(struct inode *inode, struct file *filp) +{ + int ret; + + ret = trace_user_fault_buffer_enable(); + if (ret < 0) + return ret; + + stream_open(inode, filp); + ret = tracing_open_generic_tr(inode, filp); + if (ret < 0) + trace_user_fault_buffer_disable(); + return ret; +} + +static int tracing_mark_release(struct inode *inode, struct file *file) +{ + trace_user_fault_buffer_disable(); + return tracing_release_generic_tr(inode, file); +} + static int tracing_clock_show(struct seq_file *m, void *v) { struct trace_array *tr = m->private; @@ -7764,13 +7936,13 @@ static const struct file_operations tracing_free_buffer_fops = { static const struct file_operations tracing_mark_fops = { .open = tracing_mark_open, .write = tracing_mark_write, - .release = tracing_release_generic_tr, + .release = tracing_mark_release, }; static const struct file_operations tracing_mark_raw_fops = { .open = tracing_mark_open, .write = tracing_mark_raw_write, - .release = tracing_release_generic_tr, + .release = tracing_mark_release, }; static const struct file_operations trace_clock_fops = {

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FAILED: patch "[PATCH] net: nfc: nci: Add parameter validation for packet data" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 9c328f54741bd5465ca1dc717c84c04242fac2e1 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101343-swimwear-plating-ce95@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 9c328f54741bd5465ca1dc717c84c04242fac2e1 Mon Sep 17 00:00:00 2001 From: Deepak Sharma <deepak.sharma.472935(a)gmail.com> Date: Thu, 25 Sep 2025 18:58:46 +0530 Subject: [PATCH] net: nfc: nci: Add parameter validation for packet data Syzbot reported an uninitialized value bug in nci_init_req, which was introduced by commit 5aca7966d2a7 ("Merge tag 'perf-tools-fixes-for-v6.17-2025-09-16' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools"). This bug arises due to very limited and poor input validation that was done at nic_valid_size(). This validation only validates the skb->len (directly reflects size provided at the userspace interface) with the length provided in the buffer itself (interpreted as NCI_HEADER). This leads to the processing of memory content at the address assuming the correct layout per what opcode requires there. This leads to the accesses to buffer of `skb_buff->data` which is not assigned anything yet. Following the same silent drop of packets of invalid sizes at `nic_valid_size()`, add validation of the data in the respective handlers and return error values in case of failure. Release the skb if error values are returned from handlers in `nci_nft_packet` and effectively do a silent drop Possible TODO: because we silently drop the packets, the call to `nci_request` will be waiting for completion of request and will face timeouts. These timeouts can get excessively logged in the dmesg. A proper handling of them may require to export `nci_request_cancel` (or propagate error handling from the nft packets handlers). Reported-by: syzbot+740e04c2a93467a0f8c8(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=740e04c2a93467a0f8c8 Fixes: 6a2968aaf50c ("NFC: basic NCI protocol implementation") Tested-by: syzbot+740e04c2a93467a0f8c8(a)syzkaller.appspotmail.com Cc: stable(a)vger.kernel.org Signed-off-by: Deepak Sharma <deepak.sharma.472935(a)gmail.com> Reviewed-by: Vadim Fedorenko <vadim.fedorenko(a)linux.dev> Link: https://patch.msgid.link/20250925132846.213425-1-deepak.sharma.472935@gmail… Signed-off-by: Paolo Abeni <pabeni(a)redhat.com> diff --git a/net/nfc/nci/ntf.c b/net/nfc/nci/ntf.c index a818eff27e6b..418b84e2b260 100644 --- a/net/nfc/nci/ntf.c +++ b/net/nfc/nci/ntf.c @@ -27,11 +27,16 @@ /* Handle NCI Notification packets */ -static void nci_core_reset_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_core_reset_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { /* Handle NCI 2.x core reset notification */ - const struct nci_core_reset_ntf *ntf = (void *)skb->data; + const struct nci_core_reset_ntf *ntf; + + if (skb->len < sizeof(struct nci_core_reset_ntf)) + return -EINVAL; + + ntf = (struct nci_core_reset_ntf *)skb->data; ndev->nci_ver = ntf->nci_ver; pr_debug("nci_ver 0x%x, config_status 0x%x\n", @@ -42,15 +47,22 @@ static void nci_core_reset_ntf_packet(struct nci_dev *ndev, __le32_to_cpu(ntf->manufact_specific_info); nci_req_complete(ndev, NCI_STATUS_OK); + + return 0; } -static void nci_core_conn_credits_ntf_packet(struct nci_dev *ndev, - struct sk_buff *skb) +static int nci_core_conn_credits_ntf_packet(struct nci_dev *ndev, + struct sk_buff *skb) { - struct nci_core_conn_credit_ntf *ntf = (void *) skb->data; + struct nci_core_conn_credit_ntf *ntf; struct nci_conn_info *conn_info; int i; + if (skb->len < sizeof(struct nci_core_conn_credit_ntf)) + return -EINVAL; + + ntf = (struct nci_core_conn_credit_ntf *)skb->data; + pr_debug("num_entries %d\n", ntf->num_entries); if (ntf->num_entries > NCI_MAX_NUM_CONN) @@ -68,7 +80,7 @@ static void nci_core_conn_credits_ntf_packet(struct nci_dev *ndev, conn_info = nci_get_conn_info_by_conn_id(ndev, ntf->conn_entries[i].conn_id); if (!conn_info) - return; + return 0; atomic_add(ntf->conn_entries[i].credits, &conn_info->credits_cnt); @@ -77,12 +89,19 @@ static void nci_core_conn_credits_ntf_packet(struct nci_dev *ndev, /* trigger the next tx */ if (!skb_queue_empty(&ndev->tx_q)) queue_work(ndev->tx_wq, &ndev->tx_work); + + return 0; } -static void nci_core_generic_error_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_core_generic_error_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { - __u8 status = skb->data[0]; + __u8 status; + + if (skb->len < 1) + return -EINVAL; + + status = skb->data[0]; pr_debug("status 0x%x\n", status); @@ -91,12 +110,19 @@ static void nci_core_generic_error_ntf_packet(struct nci_dev *ndev, (the state remains the same) */ nci_req_complete(ndev, status); } + + return 0; } -static void nci_core_conn_intf_error_ntf_packet(struct nci_dev *ndev, - struct sk_buff *skb) +static int nci_core_conn_intf_error_ntf_packet(struct nci_dev *ndev, + struct sk_buff *skb) { - struct nci_core_intf_error_ntf *ntf = (void *) skb->data; + struct nci_core_intf_error_ntf *ntf; + + if (skb->len < sizeof(struct nci_core_intf_error_ntf)) + return -EINVAL; + + ntf = (struct nci_core_intf_error_ntf *)skb->data; ntf->conn_id = nci_conn_id(&ntf->conn_id); @@ -105,6 +131,8 @@ static void nci_core_conn_intf_error_ntf_packet(struct nci_dev *ndev, /* complete the data exchange transaction, if exists */ if (test_bit(NCI_DATA_EXCHANGE, &ndev->flags)) nci_data_exchange_complete(ndev, NULL, ntf->conn_id, -EIO); + + return 0; } static const __u8 * @@ -329,13 +357,18 @@ void nci_clear_target_list(struct nci_dev *ndev) ndev->n_targets = 0; } -static void nci_rf_discover_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_rf_discover_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { struct nci_rf_discover_ntf ntf; - const __u8 *data = skb->data; + const __u8 *data; bool add_target = true; + if (skb->len < sizeof(struct nci_rf_discover_ntf)) + return -EINVAL; + + data = skb->data; + ntf.rf_discovery_id = *data++; ntf.rf_protocol = *data++; ntf.rf_tech_and_mode = *data++; @@ -390,6 +423,8 @@ static void nci_rf_discover_ntf_packet(struct nci_dev *ndev, nfc_targets_found(ndev->nfc_dev, ndev->targets, ndev->n_targets); } + + return 0; } static int nci_extract_activation_params_iso_dep(struct nci_dev *ndev, @@ -553,14 +588,19 @@ static int nci_store_ats_nfc_iso_dep(struct nci_dev *ndev, return NCI_STATUS_OK; } -static void nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { struct nci_conn_info *conn_info; struct nci_rf_intf_activated_ntf ntf; - const __u8 *data = skb->data; + const __u8 *data; int err = NCI_STATUS_OK; + if (skb->len < sizeof(struct nci_rf_intf_activated_ntf)) + return -EINVAL; + + data = skb->data; + ntf.rf_discovery_id = *data++; ntf.rf_interface = *data++; ntf.rf_protocol = *data++; @@ -667,7 +707,7 @@ static void nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev, if (err == NCI_STATUS_OK) { conn_info = ndev->rf_conn_info; if (!conn_info) - return; + return 0; conn_info->max_pkt_payload_len = ntf.max_data_pkt_payload_size; conn_info->initial_num_credits = ntf.initial_num_credits; @@ -721,19 +761,26 @@ static void nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev, pr_err("error when signaling tm activation\n"); } } + + return 0; } -static void nci_rf_deactivate_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_rf_deactivate_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { const struct nci_conn_info *conn_info; - const struct nci_rf_deactivate_ntf *ntf = (void *)skb->data; + const struct nci_rf_deactivate_ntf *ntf; + + if (skb->len < sizeof(struct nci_rf_deactivate_ntf)) + return -EINVAL; + + ntf = (struct nci_rf_deactivate_ntf *)skb->data; pr_debug("entry, type 0x%x, reason 0x%x\n", ntf->type, ntf->reason); conn_info = ndev->rf_conn_info; if (!conn_info) - return; + return 0; /* drop tx data queue */ skb_queue_purge(&ndev->tx_q); @@ -765,14 +812,20 @@ static void nci_rf_deactivate_ntf_packet(struct nci_dev *ndev, } nci_req_complete(ndev, NCI_STATUS_OK); + + return 0; } -static void nci_nfcee_discover_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_nfcee_discover_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { u8 status = NCI_STATUS_OK; - const struct nci_nfcee_discover_ntf *nfcee_ntf = - (struct nci_nfcee_discover_ntf *)skb->data; + const struct nci_nfcee_discover_ntf *nfcee_ntf; + + if (skb->len < sizeof(struct nci_nfcee_discover_ntf)) + return -EINVAL; + + nfcee_ntf = (struct nci_nfcee_discover_ntf *)skb->data; /* NFCForum NCI 9.2.1 HCI Network Specific Handling * If the NFCC supports the HCI Network, it SHALL return one, @@ -783,6 +836,8 @@ static void nci_nfcee_discover_ntf_packet(struct nci_dev *ndev, ndev->cur_params.id = nfcee_ntf->nfcee_id; nci_req_complete(ndev, status); + + return 0; } void nci_ntf_packet(struct nci_dev *ndev, struct sk_buff *skb) @@ -809,35 +864,43 @@ void nci_ntf_packet(struct nci_dev *ndev, struct sk_buff *skb) switch (ntf_opcode) { case NCI_OP_CORE_RESET_NTF: - nci_core_reset_ntf_packet(ndev, skb); + if (nci_core_reset_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_CORE_CONN_CREDITS_NTF: - nci_core_conn_credits_ntf_packet(ndev, skb); + if (nci_core_conn_credits_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_CORE_GENERIC_ERROR_NTF: - nci_core_generic_error_ntf_packet(ndev, skb); + if (nci_core_generic_error_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_CORE_INTF_ERROR_NTF: - nci_core_conn_intf_error_ntf_packet(ndev, skb); + if (nci_core_conn_intf_error_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_RF_DISCOVER_NTF: - nci_rf_discover_ntf_packet(ndev, skb); + if (nci_rf_discover_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_RF_INTF_ACTIVATED_NTF: - nci_rf_intf_activated_ntf_packet(ndev, skb); + if (nci_rf_intf_activated_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_RF_DEACTIVATE_NTF: - nci_rf_deactivate_ntf_packet(ndev, skb); + if (nci_rf_deactivate_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_NFCEE_DISCOVER_NTF: - nci_nfcee_discover_ntf_packet(ndev, skb); + if (nci_nfcee_discover_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_RF_NFCEE_ACTION_NTF:

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FAILED: patch "[PATCH] net: nfc: nci: Add parameter validation for packet data" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 9c328f54741bd5465ca1dc717c84c04242fac2e1 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025101341-deduct-footage-c12a@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 9c328f54741bd5465ca1dc717c84c04242fac2e1 Mon Sep 17 00:00:00 2001 From: Deepak Sharma <deepak.sharma.472935(a)gmail.com> Date: Thu, 25 Sep 2025 18:58:46 +0530 Subject: [PATCH] net: nfc: nci: Add parameter validation for packet data Syzbot reported an uninitialized value bug in nci_init_req, which was introduced by commit 5aca7966d2a7 ("Merge tag 'perf-tools-fixes-for-v6.17-2025-09-16' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools"). This bug arises due to very limited and poor input validation that was done at nic_valid_size(). This validation only validates the skb->len (directly reflects size provided at the userspace interface) with the length provided in the buffer itself (interpreted as NCI_HEADER). This leads to the processing of memory content at the address assuming the correct layout per what opcode requires there. This leads to the accesses to buffer of `skb_buff->data` which is not assigned anything yet. Following the same silent drop of packets of invalid sizes at `nic_valid_size()`, add validation of the data in the respective handlers and return error values in case of failure. Release the skb if error values are returned from handlers in `nci_nft_packet` and effectively do a silent drop Possible TODO: because we silently drop the packets, the call to `nci_request` will be waiting for completion of request and will face timeouts. These timeouts can get excessively logged in the dmesg. A proper handling of them may require to export `nci_request_cancel` (or propagate error handling from the nft packets handlers). Reported-by: syzbot+740e04c2a93467a0f8c8(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=740e04c2a93467a0f8c8 Fixes: 6a2968aaf50c ("NFC: basic NCI protocol implementation") Tested-by: syzbot+740e04c2a93467a0f8c8(a)syzkaller.appspotmail.com Cc: stable(a)vger.kernel.org Signed-off-by: Deepak Sharma <deepak.sharma.472935(a)gmail.com> Reviewed-by: Vadim Fedorenko <vadim.fedorenko(a)linux.dev> Link: https://patch.msgid.link/20250925132846.213425-1-deepak.sharma.472935@gmail… Signed-off-by: Paolo Abeni <pabeni(a)redhat.com> diff --git a/net/nfc/nci/ntf.c b/net/nfc/nci/ntf.c index a818eff27e6b..418b84e2b260 100644 --- a/net/nfc/nci/ntf.c +++ b/net/nfc/nci/ntf.c @@ -27,11 +27,16 @@ /* Handle NCI Notification packets */ -static void nci_core_reset_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_core_reset_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { /* Handle NCI 2.x core reset notification */ - const struct nci_core_reset_ntf *ntf = (void *)skb->data; + const struct nci_core_reset_ntf *ntf; + + if (skb->len < sizeof(struct nci_core_reset_ntf)) + return -EINVAL; + + ntf = (struct nci_core_reset_ntf *)skb->data; ndev->nci_ver = ntf->nci_ver; pr_debug("nci_ver 0x%x, config_status 0x%x\n", @@ -42,15 +47,22 @@ static void nci_core_reset_ntf_packet(struct nci_dev *ndev, __le32_to_cpu(ntf->manufact_specific_info); nci_req_complete(ndev, NCI_STATUS_OK); + + return 0; } -static void nci_core_conn_credits_ntf_packet(struct nci_dev *ndev, - struct sk_buff *skb) +static int nci_core_conn_credits_ntf_packet(struct nci_dev *ndev, + struct sk_buff *skb) { - struct nci_core_conn_credit_ntf *ntf = (void *) skb->data; + struct nci_core_conn_credit_ntf *ntf; struct nci_conn_info *conn_info; int i; + if (skb->len < sizeof(struct nci_core_conn_credit_ntf)) + return -EINVAL; + + ntf = (struct nci_core_conn_credit_ntf *)skb->data; + pr_debug("num_entries %d\n", ntf->num_entries); if (ntf->num_entries > NCI_MAX_NUM_CONN) @@ -68,7 +80,7 @@ static void nci_core_conn_credits_ntf_packet(struct nci_dev *ndev, conn_info = nci_get_conn_info_by_conn_id(ndev, ntf->conn_entries[i].conn_id); if (!conn_info) - return; + return 0; atomic_add(ntf->conn_entries[i].credits, &conn_info->credits_cnt); @@ -77,12 +89,19 @@ static void nci_core_conn_credits_ntf_packet(struct nci_dev *ndev, /* trigger the next tx */ if (!skb_queue_empty(&ndev->tx_q)) queue_work(ndev->tx_wq, &ndev->tx_work); + + return 0; } -static void nci_core_generic_error_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_core_generic_error_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { - __u8 status = skb->data[0]; + __u8 status; + + if (skb->len < 1) + return -EINVAL; + + status = skb->data[0]; pr_debug("status 0x%x\n", status); @@ -91,12 +110,19 @@ static void nci_core_generic_error_ntf_packet(struct nci_dev *ndev, (the state remains the same) */ nci_req_complete(ndev, status); } + + return 0; } -static void nci_core_conn_intf_error_ntf_packet(struct nci_dev *ndev, - struct sk_buff *skb) +static int nci_core_conn_intf_error_ntf_packet(struct nci_dev *ndev, + struct sk_buff *skb) { - struct nci_core_intf_error_ntf *ntf = (void *) skb->data; + struct nci_core_intf_error_ntf *ntf; + + if (skb->len < sizeof(struct nci_core_intf_error_ntf)) + return -EINVAL; + + ntf = (struct nci_core_intf_error_ntf *)skb->data; ntf->conn_id = nci_conn_id(&ntf->conn_id); @@ -105,6 +131,8 @@ static void nci_core_conn_intf_error_ntf_packet(struct nci_dev *ndev, /* complete the data exchange transaction, if exists */ if (test_bit(NCI_DATA_EXCHANGE, &ndev->flags)) nci_data_exchange_complete(ndev, NULL, ntf->conn_id, -EIO); + + return 0; } static const __u8 * @@ -329,13 +357,18 @@ void nci_clear_target_list(struct nci_dev *ndev) ndev->n_targets = 0; } -static void nci_rf_discover_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_rf_discover_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { struct nci_rf_discover_ntf ntf; - const __u8 *data = skb->data; + const __u8 *data; bool add_target = true; + if (skb->len < sizeof(struct nci_rf_discover_ntf)) + return -EINVAL; + + data = skb->data; + ntf.rf_discovery_id = *data++; ntf.rf_protocol = *data++; ntf.rf_tech_and_mode = *data++; @@ -390,6 +423,8 @@ static void nci_rf_discover_ntf_packet(struct nci_dev *ndev, nfc_targets_found(ndev->nfc_dev, ndev->targets, ndev->n_targets); } + + return 0; } static int nci_extract_activation_params_iso_dep(struct nci_dev *ndev, @@ -553,14 +588,19 @@ static int nci_store_ats_nfc_iso_dep(struct nci_dev *ndev, return NCI_STATUS_OK; } -static void nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { struct nci_conn_info *conn_info; struct nci_rf_intf_activated_ntf ntf; - const __u8 *data = skb->data; + const __u8 *data; int err = NCI_STATUS_OK; + if (skb->len < sizeof(struct nci_rf_intf_activated_ntf)) + return -EINVAL; + + data = skb->data; + ntf.rf_discovery_id = *data++; ntf.rf_interface = *data++; ntf.rf_protocol = *data++; @@ -667,7 +707,7 @@ static void nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev, if (err == NCI_STATUS_OK) { conn_info = ndev->rf_conn_info; if (!conn_info) - return; + return 0; conn_info->max_pkt_payload_len = ntf.max_data_pkt_payload_size; conn_info->initial_num_credits = ntf.initial_num_credits; @@ -721,19 +761,26 @@ static void nci_rf_intf_activated_ntf_packet(struct nci_dev *ndev, pr_err("error when signaling tm activation\n"); } } + + return 0; } -static void nci_rf_deactivate_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_rf_deactivate_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { const struct nci_conn_info *conn_info; - const struct nci_rf_deactivate_ntf *ntf = (void *)skb->data; + const struct nci_rf_deactivate_ntf *ntf; + + if (skb->len < sizeof(struct nci_rf_deactivate_ntf)) + return -EINVAL; + + ntf = (struct nci_rf_deactivate_ntf *)skb->data; pr_debug("entry, type 0x%x, reason 0x%x\n", ntf->type, ntf->reason); conn_info = ndev->rf_conn_info; if (!conn_info) - return; + return 0; /* drop tx data queue */ skb_queue_purge(&ndev->tx_q); @@ -765,14 +812,20 @@ static void nci_rf_deactivate_ntf_packet(struct nci_dev *ndev, } nci_req_complete(ndev, NCI_STATUS_OK); + + return 0; } -static void nci_nfcee_discover_ntf_packet(struct nci_dev *ndev, - const struct sk_buff *skb) +static int nci_nfcee_discover_ntf_packet(struct nci_dev *ndev, + const struct sk_buff *skb) { u8 status = NCI_STATUS_OK; - const struct nci_nfcee_discover_ntf *nfcee_ntf = - (struct nci_nfcee_discover_ntf *)skb->data; + const struct nci_nfcee_discover_ntf *nfcee_ntf; + + if (skb->len < sizeof(struct nci_nfcee_discover_ntf)) + return -EINVAL; + + nfcee_ntf = (struct nci_nfcee_discover_ntf *)skb->data; /* NFCForum NCI 9.2.1 HCI Network Specific Handling * If the NFCC supports the HCI Network, it SHALL return one, @@ -783,6 +836,8 @@ static void nci_nfcee_discover_ntf_packet(struct nci_dev *ndev, ndev->cur_params.id = nfcee_ntf->nfcee_id; nci_req_complete(ndev, status); + + return 0; } void nci_ntf_packet(struct nci_dev *ndev, struct sk_buff *skb) @@ -809,35 +864,43 @@ void nci_ntf_packet(struct nci_dev *ndev, struct sk_buff *skb) switch (ntf_opcode) { case NCI_OP_CORE_RESET_NTF: - nci_core_reset_ntf_packet(ndev, skb); + if (nci_core_reset_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_CORE_CONN_CREDITS_NTF: - nci_core_conn_credits_ntf_packet(ndev, skb); + if (nci_core_conn_credits_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_CORE_GENERIC_ERROR_NTF: - nci_core_generic_error_ntf_packet(ndev, skb); + if (nci_core_generic_error_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_CORE_INTF_ERROR_NTF: - nci_core_conn_intf_error_ntf_packet(ndev, skb); + if (nci_core_conn_intf_error_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_RF_DISCOVER_NTF: - nci_rf_discover_ntf_packet(ndev, skb); + if (nci_rf_discover_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_RF_INTF_ACTIVATED_NTF: - nci_rf_intf_activated_ntf_packet(ndev, skb); + if (nci_rf_intf_activated_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_RF_DEACTIVATE_NTF: - nci_rf_deactivate_ntf_packet(ndev, skb); + if (nci_rf_deactivate_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_NFCEE_DISCOVER_NTF: - nci_nfcee_discover_ntf_packet(ndev, skb); + if (nci_nfcee_discover_ntf_packet(ndev, skb)) + goto end; break; case NCI_OP_RF_NFCEE_ACTION_NTF:

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[PATCH] platform/x86: alienware-wmi-wmax: Fix null pointer derefence in sleep handlers

by Kurt Borja

Initialize `awcc` with empty quirks to avoid a null pointer dereference in sleep handlers for devices without the AWCC interface. This also allows some code simplification in alienware_wmax_wmi_init(). Cc: stable(a)vger.kernel.org Reported-by: Gal Hammer <galhammer(a)gmail.com> Tested-by: Gal Hammer <galhammer(a)gmail.com> Fixes: 07ac275981b1 ("platform/x86: alienware-wmi-wmax: Add support for manual fan control") Signed-off-by: Kurt Borja <kuurtb(a)gmail.com> --- drivers/platform/x86/dell/alienware-wmi-wmax.c | 24 +++++++----------------- 1 file changed, 7 insertions(+), 17 deletions(-) diff --git a/drivers/platform/x86/dell/alienware-wmi-wmax.c b/drivers/platform/x86/dell/alienware-wmi-wmax.c index 31f9643a6a3b5c2eb74b089dc071964bd6df8b43..2c4b71b03c264edaffcb0341bbd9e6acefced8b8 100644 --- a/drivers/platform/x86/dell/alienware-wmi-wmax.c +++ b/drivers/platform/x86/dell/alienware-wmi-wmax.c @@ -393,7 +393,7 @@ static const enum platform_profile_option awcc_mode_to_platform_profile[AWCC_PRO [AWCC_PROFILE_LEGACY_PERFORMANCE] = PLATFORM_PROFILE_PERFORMANCE, }; -static struct awcc_quirks *awcc; +static struct awcc_quirks *awcc = &empty_quirks; /* * The HDMI mux sysfs node indicates the status of the HDMI input mux. @@ -1680,26 +1680,16 @@ int __init alienware_wmax_wmi_init(void) if (id) awcc = id->driver_data; - if (force_hwmon) { - if (!awcc) - awcc = &empty_quirks; - + if (force_hwmon) awcc->hwmon = true; - } - - if (force_platform_profile) { - if (!awcc) - awcc = &empty_quirks; + if (force_platform_profile) awcc->pprof = true; - } - if (force_gmode) { - if (awcc) - awcc->gmode = true; - else - pr_warn("force_gmode requires platform profile support\n"); - } + if (force_gmode && awcc->pprof) + awcc->gmode = true; + else + pr_warn("force_gmode requires platform profile support\n"); return wmi_driver_register(&alienware_wmax_wmi_driver); } --- base-commit: 3ed17349f18774c24505b0c21dfbd3cc4f126518 change-id: 20251012-sleep-fix-5d0596dd92a3 -- ~ Kurt

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[PATCH v2] dt-bindings: usb: qcom,snps-dwc3: Fix bindings for X1E80100

by Krishna Kurapati

Add the missing multiport controller binding to target list. Fix minItems for interrupt-names to avoid the following error on High Speed controller: usb@a200000: interrupt-names: ['dwc_usb3', 'pwr_event', 'dp_hs_phy_irq', 'dm_hs_phy_irq'] is too short Fixes: 6e762f7b8edc ("dt-bindings: usb: Introduce qcom,snps-dwc3") Cc: stable(a)vger.kernel.org Signed-off-by: Krishna Kurapati <krishna.kurapati(a)oss.qualcomm.com> --- Changes in v2: Added fixes tag and put error log in one line. Link to v1: https://lore.kernel.org/all/20251013011357.732151-1-krishna.kurapati@oss.qu… Documentation/devicetree/bindings/usb/qcom,snps-dwc3.yaml | 3 +++ 1 file changed, 3 insertions(+) diff --git a/Documentation/devicetree/bindings/usb/qcom,snps-dwc3.yaml b/Documentation/devicetree/bindings/usb/qcom,snps-dwc3.yaml index dfd084ed9024..d49a58d5478f 100644 --- a/Documentation/devicetree/bindings/usb/qcom,snps-dwc3.yaml +++ b/Documentation/devicetree/bindings/usb/qcom,snps-dwc3.yaml @@ -68,6 +68,7 @@ properties: - qcom,sm8550-dwc3 - qcom,sm8650-dwc3 - qcom,x1e80100-dwc3 + - qcom,x1e80100-dwc3-mp - const: qcom,snps-dwc3 reg: @@ -460,8 +461,10 @@ allOf: then: properties: interrupts: + minItems: 4 maxItems: 5 interrupt-names: + minItems: 4 items: - const: dwc_usb3 - const: pwr_event -- 2.34.1

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[PATCH] pidfs: fix ERR_PTR dereference in pidfd_info()

by Zhen Ni

pidfd_pid() may return an ERR_PTR() when the file does not refer to a valid pidfs file. Currently pidfd_info() calls pid_in_current_pidns() directly on the returned value, which risks dereferencing an ERR_PTR. Fix it by explicitly checking IS_ERR(pid) and returning PTR_ERR(pid) before further use. Fixes: 7477d7dce48a ("pidfs: allow to retrieve exit information") Cc: stable(a)vger.kernel.org Signed-off-by: Zhen Ni <zhen.ni(a)easystack.cn> --- fs/pidfs.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/pidfs.c b/fs/pidfs.c index 0ef5b47d796a..16670648bb09 100644 --- a/fs/pidfs.c +++ b/fs/pidfs.c @@ -314,6 +314,9 @@ static long pidfd_info(struct file *file, unsigned int cmd, unsigned long arg) if (copy_from_user(&mask, &uinfo->mask, sizeof(mask))) return -EFAULT; + if (IS_ERR(pid)) + return PTR_ERR(pid); + /* * Restrict information retrieval to tasks within the caller's pid * namespace hierarchy. -- 2.20.1

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Re: Patch "hugetlbfs: skip VMAs without shareable locks in hugetlb_vmdelete_list" has been added to the 6.16-stable tree

by Deepanshu Kartikey

Hi Sasha, Please do NOT backport commit dd83609b8898 alone to stable. This patch causes a regression in fallocate(PUNCH_HOLE) operations where pages are not freed immediately, as reported by Mark Brown. The fix for this regression is already in linux-next as commit 91a830422707 ("hugetlbfs: check for shareable lock before calling huge_pmd_unshare()"). Please backport both commits together to avoid introducing the regression in stable kernels: - dd83609b88986f4add37c0871c3434310652ebd5 ("hugetlbfs: skip VMAs without shareable locks in hugetlb_vmdelete_list") - 91a830422707a62629fc4fbf8cdc3c8acf56ca64 ("hugetlbfs: check for shareable lock before calling huge_pmd_unshare()") Thanks, Deepanshu Kartikey

1 month, 1 week

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[PATCH] net: usb: lan78xx: Fix lost EEPROM write timeout error(-ETIMEDOUT) in lan78xx_write_raw_eeprom

by Bhanu Seshu Kumar Valluri

The function lan78xx_write_raw_eeprom failed to properly propagate EEPROM write timeout errors (-ETIMEDOUT). In the timeout fallthrough path, it first attempted to restore the pin configuration for LED outputs and then returned only the status of that restore operation, discarding the original timeout error saved in ret. As a result, callers could mistakenly treat EEPROM write operation as successful even though the EEPROM write had actually timed out with no or partial data write. To fix this, handle errors in restoring the LED pin configuration separately. If the restore succeeds, return any prior EEPROM write timeout error saved in ret to the caller. Suggested-by: Oleksij Rempel <o.rempel(a)pengutronix.de> Fixes: 8b1b2ca83b20 ("net: usb: lan78xx: Improve error handling in EEPROM and OTP operations") cc: stable(a)vger.kernel.org Signed-off-by: Bhanu Seshu Kumar Valluri <bhanuseshukumar(a)gmail.com> --- Note: The patch is compiled and tested using EVB-LAN7800LC. The patch was suggested by Oleksij Rempel while reviewing a fix to a bug found by syzbot earlier. The review mail chain where this fix was suggested is given below. https://lore.kernel.org/all/aNzojoXK-m1Tn6Lc@pengutronix.de/ ChangeLog: v1->v2: Added cc:stable tag as asked during v1 review. V1 Link : https://lore.kernel.org/all/20251004040722.82882-1-bhanuseshukumar@gmail.co… drivers/net/usb/lan78xx.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c index d75502ebbc0d..5ccbe6ae2ebe 100644 --- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -1174,10 +1174,13 @@ static int lan78xx_write_raw_eeprom(struct lan78xx_net *dev, u32 offset, } write_raw_eeprom_done: - if (dev->chipid == ID_REV_CHIP_ID_7800_) - return lan78xx_write_reg(dev, HW_CFG, saved); - - return 0; + if (dev->chipid == ID_REV_CHIP_ID_7800_) { + int rc = lan78xx_write_reg(dev, HW_CFG, saved); + /* If USB fails, there is nothing to do */ + if (rc < 0) + return rc; + } + return ret; } static int lan78xx_read_raw_otp(struct lan78xx_net *dev, u32 offset, -- 2.34.1

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