- Linux-stable-mirror - lists.linaro.org

[PATCH 0/4] mm, swap: misc cleanup and bugfix

by Kairui Song

A few cleanups and a bugfix that are either suitable after the swap table phase I or found during code review. Patch 1 is a bugfix and needs to be included in the stable branch, the rest have no behavior change. --- Kairui Song (4): mm, swap: do not perform synchronous discard during allocation mm, swap: rename helper for setup bad slots mm, swap: cleanup swap entry allocation parameter mm/migrate, swap: drop usage of folio_index include/linux/swap.h | 4 ++-- mm/migrate.c | 4 ++-- mm/shmem.c | 2 +- mm/swap.h | 21 ----------------- mm/swapfile.c | 64 ++++++++++++++++++++++++++++++++++++---------------- mm/vmscan.c | 4 ++-- 6 files changed, 52 insertions(+), 47 deletions(-) --- base-commit: 53e573001f2b5168f9b65d2b79e9563a3b479c17 change-id: 20251007-swap-clean-after-swap-table-p1-b9a7635ee3fa Best regards, -- Kairui Song <kasong(a)tencent.com>

3 hours, 52 minutes

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[PATCH AUTOSEL 6.17-6.6] hwmon: (k10temp) Add device ID for Strix Halo

by Sasha Levin

From: Rong Zhang <i(a)rong.moe> [ Upstream commit e5d1e313d7b6272d6dfda983906d99f97ad9062b ] The device ID of Strix Halo Data Fabric Function 3 has been in the tree since commit 0e640f0a47d8 ("x86/amd_nb: Add new PCI IDs for AMD family 0x1a"), but is somehow missing from k10temp_id_table. Add it so that it works out of the box. Tested on Beelink GTR9 Pro Mini PC. Signed-off-by: Rong Zhang <i(a)rong.moe> Reviewed-by: Mario Limonciello <mario.limonciello(a)amd.com> Link: https://lore.kernel.org/r/20250823180443.85512-1-i@rong.moe Signed-off-by: Guenter Roeck <linux(a)roeck-us.net> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- LLM Generated explanations, may be completely bogus: YES – the added ID lets the existing k10temp driver bind to Strix Halo’s DF3 device so users get temperature readings on that platform. - `drivers/hwmon/k10temp.c:560` gains `PCI_DEVICE_ID_AMD_1AH_M70H_DF_F3`, fixing the current omission that prevents the module from attaching to Strix Halo’s Data Fabric function 3 and leaves its sensors unavailable. - The constant already exists in released kernels (`include/linux/pci_ids.h:587`) and is used by the AMD northbridge driver (`arch/x86/kernel/amd_nb.c:98`), so the new table entry simply connects existing infrastructure; no functional code paths change. - Scope is minimal (one ID entry, no new logic), making regression risk negligible; the patch has been verified on shipping hardware (Beelink GTR9 Pro). - For stable backports, this applies cleanly to branches ≥ v6.10 where the PCI ID is defined; older long-term trees would first need commit 0e640f0a47d8 (or an equivalent definition). Natural next step: backport to the relevant stable lines that already carry the Strix Halo PCI ID definition (6.10.y, upcoming 6.11.y, etc.). drivers/hwmon/k10temp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/hwmon/k10temp.c b/drivers/hwmon/k10temp.c index 2f90a2e9ad496..b98d5ec72c4ff 100644 --- a/drivers/hwmon/k10temp.c +++ b/drivers/hwmon/k10temp.c @@ -565,6 +565,7 @@ static const struct pci_device_id k10temp_id_table[] = { { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_1AH_M20H_DF_F3) }, { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_1AH_M50H_DF_F3) }, { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_1AH_M60H_DF_F3) }, + { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_1AH_M70H_DF_F3) }, { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_1AH_M90H_DF_F3) }, { PCI_VDEVICE(HYGON, PCI_DEVICE_ID_AMD_17H_DF_F3) }, {} -- 2.51.0

4 hours, 13 minutes

5
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[PATCH] exfat: fix out-of-bounds in exfat_nls_to_ucs2()

by Jeongjun Park

After the loop that converts characters to ucs2 ends, the variable i may be greater than or equal to len. However, when checking whether the last byte of p_cstring is NULL, the variable i is used as is, resulting in an out-of-bounds read if i >= len. Therefore, to prevent this, we need to modify the function to check whether i is less than len, and if i is greater than or equal to len, to check p_cstring[len - 1] byte. Cc: <stable(a)vger.kernel.org> Reported-by: syzbot+98cc76a76de46b3714d4(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=98cc76a76de46b3714d4 Fixes: 370e812b3ec1 ("exfat: add nls operations") Signed-off-by: Jeongjun Park <aha310510(a)gmail.com> --- fs/exfat/nls.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/exfat/nls.c b/fs/exfat/nls.c index 8243d94ceaf4..a52f3494eb20 100644 --- a/fs/exfat/nls.c +++ b/fs/exfat/nls.c @@ -616,7 +616,7 @@ static int exfat_nls_to_ucs2(struct super_block *sb, unilen++; } - if (p_cstring[i] != '\0') + if (p_cstring[min(i, len - 1)] != '\0') lossy |= NLS_NAME_OVERLEN; *uniname = '\0'; --

4 hours, 23 minutes

3
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[PATCH v2 00/10] pmdomain: samsung: add supoort for Google GS101

by André Draszik

Hi, This series adds support for the power domains on Google GS101. It's fairly similar to SoCs already supported by this driver, except that register acces does not work via plain ioremap() / readl() / writel(). Instead, the regmap created by the PMU driver must be used (which uses Arm SMCC calls under the hood). The DT update to add the new required properties on gs101 will be posted separately. Signed-off-by: André Draszik <andre.draszik(a)linaro.org> --- Changes in v2: - Krzysztof: - move google,gs101-pmu binding into separate file - mark devm_kstrdup_const() patch as fix - use bool for need_early_sync_state - merge patches 8 and 10 from v1 series into one patch - collect tags - Link to v1: https://lore.kernel.org/r/20251006-gs101-pd-v1-0-f0cb0c01ea7b@linaro.org --- André Draszik (10): dt-bindings: power: samsung: add google,gs101-pd dt-bindings: soc: samsung: exynos-pmu: move gs101-pmu into separate binding dt-bindings: soc: samsung: gs101-pmu: allow power domains as children pmdomain: samsung: plug potential memleak during probe pmdomain: samsung: convert to using regmap pmdomain: samsung: convert to regmap_read_poll_timeout() pmdomain: samsung: don't hardcode offset for registers to 0 and 4 pmdomain: samsung: selectively handle enforced sync_state pmdomain: samsung: add support for google,gs101-pd pmdomain: samsung: use dev_err() instead of pr_err() .../devicetree/bindings/power/pd-samsung.yaml | 1 + .../bindings/soc/google/google,gs101-pmu.yaml | 107 +++++++++++++++++ .../bindings/soc/samsung/exynos-pmu.yaml | 20 ---- MAINTAINERS | 1 + drivers/pmdomain/samsung/exynos-pm-domains.c | 126 +++++++++++++++------ 5 files changed, 201 insertions(+), 54 deletions(-) --- base-commit: a5f97c90e75f09f24ece2dca34168722b140a798 change-id: 20251001-gs101-pd-d4dc97d70a84 Best regards, -- André Draszik <andre.draszik(a)linaro.org>

5 hours, 26 minutes

1
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[for-linus][PATCH 5/5] tracing: Have trace_marker use per-cpu data to read user space

by Steven Rostedt

From: Steven Rostedt <rostedt(a)goodmis.org> 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> --- kernel/trace/trace.c | 268 +++++++++++++++++++++++++++++++++++-------- 1 file changed, 220 insertions(+), 48 deletions(-) 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 = { -- 2.51.0

5 hours, 27 minutes

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[for-linus][PATCH 4/5] ring buffer: Propagate __rb_map_vma return value to caller

by Steven Rostedt

From: Ankit Khushwaha <ankitkhushwaha.linux(a)gmail.com> The return value from `__rb_map_vma()`, which rejects writable or executable mappings (VM_WRITE, VM_EXEC, or !VM_MAYSHARE), was being ignored. As a result the caller of `__rb_map_vma` always returned 0 even when the mapping had actually failed, allowing it to proceed with an invalid VMA. Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Link: https://lore.kernel.org/20251008172516.20697-1-ankitkhushwaha.linux@gmail.c… Fixes: 117c39200d9d7 ("ring-buffer: Introducing ring-buffer mapping functions") Reported-by: syzbot+ddc001b92c083dbf2b97(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?id=194151be8eaebd826005329b2e123aecae714b… Signed-off-by: Ankit Khushwaha <ankitkhushwaha.linux(a)gmail.com> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/ring_buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 43460949ad3f..1244d2c5c384 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -7273,7 +7273,7 @@ int ring_buffer_map(struct trace_buffer *buffer, int cpu, atomic_dec(&cpu_buffer->resize_disabled); } - return 0; + return err; } int ring_buffer_unmap(struct trace_buffer *buffer, int cpu) -- 2.51.0

5 hours, 27 minutes

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[for-linus][PATCH 3/5] tracing: Fix irqoff tracers on failure of acquiring calltime

by Steven Rostedt

From: Steven Rostedt <rostedt(a)goodmis.org> The functions irqsoff_graph_entry() and irqsoff_graph_return() both call func_prolog_dec() that will test if the data->disable is already set and if not, increment it and return. If it was set, it returns false and the caller exits. The caller of this function must decrement the disable counter, but misses doing so if the calltime fails to be acquired. Instead of exiting out when calltime is NULL, change the logic to do the work if it is not NULL and still do the clean up at the end of the function if it is NULL. Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Link: https://lore.kernel.org/20251008114943.6f60f30f@gandalf.local.home Fixes: a485ea9e3ef3 ("tracing: Fix irqsoff and wakeup latency tracers when using function graph") Reported-by: Sasha Levin <sashal(a)kernel.org> Closes: https://lore.kernel.org/linux-trace-kernel/20251006175848.1906912-2-sashal@… Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/trace_irqsoff.c | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 5496758b6c76..4c45c49b06c8 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -184,7 +184,7 @@ static int irqsoff_graph_entry(struct ftrace_graph_ent *trace, unsigned long flags; unsigned int trace_ctx; u64 *calltime; - int ret; + int ret = 0; if (ftrace_graph_ignore_func(gops, trace)) return 0; @@ -202,13 +202,11 @@ static int irqsoff_graph_entry(struct ftrace_graph_ent *trace, return 0; calltime = fgraph_reserve_data(gops->idx, sizeof(*calltime)); - if (!calltime) - return 0; - - *calltime = trace_clock_local(); - - trace_ctx = tracing_gen_ctx_flags(flags); - ret = __trace_graph_entry(tr, trace, trace_ctx); + if (calltime) { + *calltime = trace_clock_local(); + trace_ctx = tracing_gen_ctx_flags(flags); + ret = __trace_graph_entry(tr, trace, trace_ctx); + } local_dec(&data->disabled); return ret; @@ -233,11 +231,10 @@ static void irqsoff_graph_return(struct ftrace_graph_ret *trace, rettime = trace_clock_local(); calltime = fgraph_retrieve_data(gops->idx, &size); - if (!calltime) - return; - - trace_ctx = tracing_gen_ctx_flags(flags); - __trace_graph_return(tr, trace, trace_ctx, *calltime, rettime); + if (calltime) { + trace_ctx = tracing_gen_ctx_flags(flags); + __trace_graph_return(tr, trace, trace_ctx, *calltime, rettime); + } local_dec(&data->disabled); } -- 2.51.0

5 hours, 27 minutes

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[for-linus][PATCH 2/5] tracing: Fix wakeup tracers on failure of acquiring calltime

by Steven Rostedt

From: Steven Rostedt <rostedt(a)goodmis.org> The functions wakeup_graph_entry() and wakeup_graph_return() both call func_prolog_preempt_disable() that will test if the data->disable is already set and if not, increment it and disable preemption. If it was set, it returns false and the caller exits. The caller of this function must decrement the disable counter, but misses doing so if the calltime fails to be acquired. Instead of exiting out when calltime is NULL, change the logic to do the work if it is not NULL and still do the clean up at the end of the function if it is NULL. Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Link: https://lore.kernel.org/20251008114835.027b878a@gandalf.local.home Fixes: a485ea9e3ef3 ("tracing: Fix irqsoff and wakeup latency tracers when using function graph") Reported-by: Sasha Levin <sashal(a)kernel.org> Closes: https://lore.kernel.org/linux-trace-kernel/20251006175848.1906912-1-sashal@… Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/trace_sched_wakeup.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index bf1cb80742ae..e3f2e4f56faa 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -138,12 +138,10 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace, return 0; calltime = fgraph_reserve_data(gops->idx, sizeof(*calltime)); - if (!calltime) - return 0; - - *calltime = trace_clock_local(); - - ret = __trace_graph_entry(tr, trace, trace_ctx); + if (calltime) { + *calltime = trace_clock_local(); + ret = __trace_graph_entry(tr, trace, trace_ctx); + } local_dec(&data->disabled); preempt_enable_notrace(); @@ -169,12 +167,10 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace, rettime = trace_clock_local(); calltime = fgraph_retrieve_data(gops->idx, &size); - if (!calltime) - return; + if (calltime) + __trace_graph_return(tr, trace, trace_ctx, *calltime, rettime); - __trace_graph_return(tr, trace, trace_ctx, *calltime, rettime); local_dec(&data->disabled); - preempt_enable_notrace(); return; } -- 2.51.0

5 hours, 27 minutes

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Bug: Performance regression in 1013af4f585f: mm/hugetlb: fix huge_pmd_unshare() vs GUP-fast race

by Uschakow, Stanislav

Hello. We have observed a huge latency increase using `fork()` after ingesting the CVE-2025-38085 fix which leads to the commit `1013af4f585f: mm/hugetlb: fix huge_pmd_unshare() vs GUP-fast race`. On large machines with 1.5TB of memory with 196 cores, we identified mmapping of 1.2TB of shared memory and forking itself dozens or hundreds of times we see a increase of execution times of a factor of 4. The reproducer is at the end of the email. Comparing the a kernel without this patch with a kernel with this patch applied when spawning 1000 children we see those execution times: Patched kernel: $ time make stress ... real 0m11.275s user 0m0.177s sys 0m23.905s Original kernel : $ time make stress ...real 0m2.475s user 0m1.398s sys 0m2.501s The patch in question: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id… My observation/assumption is: each child touches 100 random pages and despawns on each despawn `huge_pmd_unshare()` is called each call to `huge_pmd_unshare()` syncrhonizes all threads using `tlb_remove_table_sync_one()` leading to the regression I'm happy to provide more information. Thank you Stanislav Uschakow === Reproducer === Setup: #!/bin/bash echo "Setting up hugepages for reproduction..." # hugepages (1.2TB / 2MB = 614400 pages) REQUIRED_PAGES=614400 # Check current hugepage allocation CURRENT_PAGES=$(cat /proc/sys/vm/nr_hugepages) echo "Current hugepages: $CURRENT_PAGES" if [ "$CURRENT_PAGES" -lt "$REQUIRED_PAGES" ]; then echo "Allocating $REQUIRED_PAGES hugepages..." echo $REQUIRED_PAGES | sudo tee /proc/sys/vm/nr_hugepages ALLOCATED=$(cat /proc/sys/vm/nr_hugepages) echo "Allocated hugepages: $ALLOCATED" if [ "$ALLOCATED" -lt "$REQUIRED_PAGES" ]; then echo "Warning: Could not allocate all required hugepages" echo "Available: $ALLOCATED, Required: $REQUIRED_PAGES" fi fi echo never | sudo tee /sys/kernel/mm/transparent_hugepage/enabled echo -e "\nHugepage information:" cat /proc/meminfo | grep -i huge echo -e "\nSetup complete. You can now run the reproduction test." Makefile: CXX = gcc CXXFLAGS = -O2 -Wall TARGET = hugepage_repro SOURCE = hugepage_repro.c $(TARGET): $(SOURCE) $(CXX) $(CXXFLAGS) -o $(TARGET) $(SOURCE) clean: rm -f $(TARGET) setup: chmod +x setup_hugepages.sh ./setup_hugepages.sh test: $(TARGET) ./$(TARGET) 20 3 stress: $(TARGET) ./$(TARGET) 1000 1 .PHONY: clean setup test stress hugepage_repro.c: #include <sys/mman.h> #include <sys/wait.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <time.h> #include <stdio.h> #define HUGEPAGE_SIZE (2 * 1024 * 1024) // 2MB #define TOTAL_SIZE (1200ULL * 1024 * 1024 * 1024) // 1.2TB #define NUM_HUGEPAGES (TOTAL_SIZE / HUGEPAGE_SIZE) void* create_hugepage_mapping() { void* addr = mmap(NULL, TOTAL_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0); if (addr == MAP_FAILED) { perror("mmap hugepages failed"); exit(1); } return addr; } void touch_random_pages(void* addr, int num_touches) { char* base = (char*)addr; for (int i = 0; i < num_touches; ++i) { size_t offset = (rand() % NUM_HUGEPAGES) * HUGEPAGE_SIZE; volatile char val = base[offset]; (void)val; } } void child_process(void* shared_mem, int child_id) { struct timespec start, end; clock_gettime(CLOCK_MONOTONIC, &start); touch_random_pages(shared_mem, 100); clock_gettime(CLOCK_MONOTONIC, &end); long duration = (end.tv_sec - start.tv_sec) * 1000000 + (end.tv_nsec - start.tv_nsec) / 1000; printf("Child %d completed in %ld μs\n", child_id, duration); } int main(int argc, char* argv[]) { int num_processes = argc > 1 ? atoi(argv[1]) : 50; int iterations = argc > 2 ? atoi(argv[2]) : 5; printf("Creating %lluGB hugepage mapping...\n", TOTAL_SIZE / (1024*1024*1024)); void* shared_mem = create_hugepage_mapping(); for (int iter = 0; iter < iterations; ++iter) { printf("\nIteration %d: Forking %d processes\n", iter + 1, num_processes); pid_t children[num_processes]; struct timespec iter_start, iter_end; clock_gettime(CLOCK_MONOTONIC, &iter_start); for (int i = 0; i < num_processes; ++i) { pid_t pid = fork(); if (pid == 0) { child_process(shared_mem, i); exit(0); } else if (pid > 0) { children[i] = pid; } } for (int i = 0; i < num_processes; ++i) { waitpid(children[i], NULL, 0); } clock_gettime(CLOCK_MONOTONIC, &iter_end); long iter_duration = (iter_end.tv_sec - iter_start.tv_sec) * 1000 + (iter_end.tv_nsec - iter_start.tv_nsec) / 1000000; printf("Iteration completed in %ld ms\n", iter_duration); } munmap(shared_mem, TOTAL_SIZE); return 0; } Amazon Web Services Development Center Germany GmbH Tamara-Danz-Str. 13 10243 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B Sitz: Berlin Ust-ID: DE 365 538 597

5 hours, 45 minutes

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[PATCH bpf] xsk: harden userspace-supplied &xdp_desc validation

by Alexander Lobakin

Turned out certain clearly invalid values passed in &xdp_desc from userspace can pass xp_{,un}aligned_validate_desc() and then lead to UBs or just invalid frames to be queued for xmit. desc->len close to ``U32_MAX`` with a non-zero pool->tx_metadata_len can cause positive integer overflow and wraparound, the same way low enough desc->addr with a non-zero pool->tx_metadata_len can cause negative integer overflow. Both scenarios can then pass the validation successfully. This doesn't happen with valid XSk applications, but can be used to perform attacks. Always promote desc->len to ``u64`` first to exclude positive overflows of it. Use explicit check_{add,sub}_overflow() when validating desc->addr (which is ``u64`` already). bloat-o-meter reports a little growth of the code size: add/remove: 0/0 grow/shrink: 2/1 up/down: 60/-16 (44) Function old new delta xskq_cons_peek_desc 299 330 +31 xsk_tx_peek_release_desc_batch 973 1002 +29 xsk_generic_xmit 3148 3132 -16 but hopefully this doesn't hurt the performance much. Fixes: 341ac980eab9 ("xsk: Support tx_metadata_len") Cc: stable(a)vger.kernel.org # 6.8+ Signed-off-by: Alexander Lobakin <aleksander.lobakin(a)intel.com> --- net/xdp/xsk_queue.h | 45 +++++++++++++++++++++++++++++++++++---------- 1 file changed, 35 insertions(+), 10 deletions(-) diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h index f16f390370dc..1eb8d9f8b104 100644 --- a/net/xdp/xsk_queue.h +++ b/net/xdp/xsk_queue.h @@ -143,14 +143,24 @@ static inline bool xp_unused_options_set(u32 options) static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc) { - u64 addr = desc->addr - pool->tx_metadata_len; - u64 len = desc->len + pool->tx_metadata_len; - u64 offset = addr & (pool->chunk_size - 1); + u64 len = desc->len; + u64 addr, offset; - if (!desc->len) + if (!len) return false; - if (offset + len > pool->chunk_size) + /* Can overflow if desc->addr < pool->tx_metadata_len */ + if (check_sub_overflow(desc->addr, pool->tx_metadata_len, &addr)) + return false; + + offset = addr & (pool->chunk_size - 1); + + /* + * Can't overflow: @offset is guaranteed to be < ``U32_MAX`` + * (pool->chunk_size is ``u32``), @len is guaranteed + * to be <= ``U32_MAX``. + */ + if (offset + len + pool->tx_metadata_len > pool->chunk_size) return false; if (addr >= pool->addrs_cnt) @@ -158,27 +168,42 @@ static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool, if (xp_unused_options_set(desc->options)) return false; + return true; } static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc) { - u64 addr = xp_unaligned_add_offset_to_addr(desc->addr) - pool->tx_metadata_len; - u64 len = desc->len + pool->tx_metadata_len; + u64 len = desc->len; + u64 addr, end; - if (!desc->len) + if (!len) return false; + /* Can't overflow: @len is guaranteed to be <= ``U32_MAX`` */ + len += pool->tx_metadata_len; if (len > pool->chunk_size) return false; - if (addr >= pool->addrs_cnt || addr + len > pool->addrs_cnt || - xp_desc_crosses_non_contig_pg(pool, addr, len)) + /* Can overflow if desc->addr is close to 0 */ + if (check_sub_overflow(xp_unaligned_add_offset_to_addr(desc->addr), + pool->tx_metadata_len, &addr)) + return false; + + if (addr >= pool->addrs_cnt) + return false; + + /* Can overflow if pool->addrs_cnt is high enough */ + if (check_add_overflow(addr, len, &end) || end > pool->addrs_cnt) + return false; + + if (xp_desc_crosses_non_contig_pg(pool, addr, len)) return false; if (xp_unused_options_set(desc->options)) return false; + return true; } -- 2.51.0

5 hours, 45 minutes

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