March 2024 - Linux-stable-mirror

[PATCH v4 1/2] ring-buffer: Use wait_event_interruptible() in ring_buffer_wait()

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Convert ring_buffer_wait() over to wait_event_interruptible(). The default condition is to execute the wait loop inside __wait_event() just once. This does not change the ring_buffer_wait() prototype yet, but restructures the code so that it can take a "cond" and "data" parameter and will call wait_event_interruptible() with a helper function as the condition. The helper function (rb_wait_cond) takes the cond function and data parameters. It will first check if the buffer hit the watermark defined by the "full" parameter and then call the passed in condition parameter. If either are true, it returns true. If rb_wait_cond() does not return true, it will set the appropriate "waiters_pending" flag and returns false. Link: https://lore.kernel.org/linux-trace-kernel/CAHk-=wgsNgewHFxZAJiAQznwPMqEtQm… Cc: stable(a)vger.kernel.org Fixes: f3ddb74ad0790 ("tracing: Wake up ring buffer waiters on closing of the file") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- include/linux/ring_buffer.h | 1 + kernel/trace/ring_buffer.c | 116 +++++++++++++++++++++--------------- 2 files changed, 69 insertions(+), 48 deletions(-) diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index fa802db216f9..338a33db1577 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -98,6 +98,7 @@ __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *k __ring_buffer_alloc((size), (flags), &__key); \ }) +typedef bool (*ring_buffer_cond_fn)(void *data); int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full); __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, struct file *filp, poll_table *poll_table, int full); diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 6ef763f57c66..c198ba466853 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -842,43 +842,15 @@ static bool rb_watermark_hit(struct trace_buffer *buffer, int cpu, int full) return ret; } -/** - * ring_buffer_wait - wait for input to the ring buffer - * @buffer: buffer to wait on - * @cpu: the cpu buffer to wait on - * @full: wait until the percentage of pages are available, if @cpu != RING_BUFFER_ALL_CPUS - * - * If @cpu == RING_BUFFER_ALL_CPUS then the task will wake up as soon - * as data is added to any of the @buffer's cpu buffers. Otherwise - * it will wait for data to be added to a specific cpu buffer. - */ -int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full) +static inline bool +rb_wait_cond(struct rb_irq_work *rbwork, struct trace_buffer *buffer, + int cpu, int full, ring_buffer_cond_fn cond, void *data) { - struct ring_buffer_per_cpu *cpu_buffer; - DEFINE_WAIT(wait); - struct rb_irq_work *work; - int ret = 0; - - /* - * Depending on what the caller is waiting for, either any - * data in any cpu buffer, or a specific buffer, put the - * caller on the appropriate wait queue. - */ - if (cpu == RING_BUFFER_ALL_CPUS) { - work = &buffer->irq_work; - /* Full only makes sense on per cpu reads */ - full = 0; - } else { - if (!cpumask_test_cpu(cpu, buffer->cpumask)) - return -ENODEV; - cpu_buffer = buffer->buffers[cpu]; - work = &cpu_buffer->irq_work; - } + if (rb_watermark_hit(buffer, cpu, full)) + return true; - if (full) - prepare_to_wait(&work->full_waiters, &wait, TASK_INTERRUPTIBLE); - else - prepare_to_wait(&work->waiters, &wait, TASK_INTERRUPTIBLE); + if (cond(data)) + return true; /* * The events can happen in critical sections where @@ -901,27 +873,75 @@ int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full) * a task has been queued. It's OK for spurious wake ups. */ if (full) - work->full_waiters_pending = true; + rbwork->full_waiters_pending = true; else - work->waiters_pending = true; + rbwork->waiters_pending = true; - if (rb_watermark_hit(buffer, cpu, full)) - goto out; + return false; +} - if (signal_pending(current)) { - ret = -EINTR; - goto out; +/* + * The default wait condition for ring_buffer_wait() is to just to exit the + * wait loop the first time it is woken up. + */ +static bool rb_wait_once(void *data) +{ + long *once = data; + + /* wait_event() actually calls this twice before scheduling*/ + if (*once > 1) + return true; + + (*once)++; + return false; +} + +/** + * ring_buffer_wait - wait for input to the ring buffer + * @buffer: buffer to wait on + * @cpu: the cpu buffer to wait on + * @full: wait until the percentage of pages are available, if @cpu != RING_BUFFER_ALL_CPUS + * + * If @cpu == RING_BUFFER_ALL_CPUS then the task will wake up as soon + * as data is added to any of the @buffer's cpu buffers. Otherwise + * it will wait for data to be added to a specific cpu buffer. + */ +int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full) +{ + struct ring_buffer_per_cpu *cpu_buffer; + struct wait_queue_head *waitq; + ring_buffer_cond_fn cond; + struct rb_irq_work *rbwork; + void *data; + long once = 0; + int ret = 0; + + cond = rb_wait_once; + data = &once; + + /* + * Depending on what the caller is waiting for, either any + * data in any cpu buffer, or a specific buffer, put the + * caller on the appropriate wait queue. + */ + if (cpu == RING_BUFFER_ALL_CPUS) { + rbwork = &buffer->irq_work; + /* Full only makes sense on per cpu reads */ + full = 0; + } else { + if (!cpumask_test_cpu(cpu, buffer->cpumask)) + return -ENODEV; + cpu_buffer = buffer->buffers[cpu]; + rbwork = &cpu_buffer->irq_work; } - schedule(); - out: if (full) - finish_wait(&work->full_waiters, &wait); + waitq = &rbwork->full_waiters; else - finish_wait(&work->waiters, &wait); + waitq = &rbwork->waiters; - if (!ret && !rb_watermark_hit(buffer, cpu, full) && signal_pending(current)) - ret = -EINTR; + ret = wait_event_interruptible((*waitq), + rb_wait_cond(rbwork, buffer, cpu, full, cond, data)); return ret; } -- 2.43.0

9 months, 3 weeks

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[PATCH v3 2/2] tracing/ring-buffer: Fix wait_on_pipe() race

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> When the trace_pipe_raw file is closed, there should be no new readers on the file descriptor. This is mostly handled with the waking and wait_index fields of the iterator. But there's still a slight race. CPU 0 CPU 1 ----- ----- wait_index++; index = wait_index; ring_buffer_wake_waiters(); wait_on_pipe() ring_buffer_wait(); The ring_buffer_wait() will miss the wakeup from CPU 1. The problem is that the ring_buffer_wait() needs the logic of: prepare_to_wait(); if (!condition) schedule(); Where the missing condition check is the iter->wait_index update. Have the ring_buffer_wait() take a conditional callback function and a data parameter that can be used within the wait_event_interruptible() of the ring_buffer_wait() function. In wait_on_pipe(), pass a condition function that will check if the wait_index has been updated, if it has, it will return true to break out of the wait_event_interruptible() loop. Create a new field "closed" in the trace_iterator and set it in the .flush() callback before calling ring_buffer_wake_waiters(). This will keep any new readers from waiting on a closed file descriptor. Have the wait_on_pipe() condition callback also check the closed field. Change the wait_index field of the trace_iterator to atomic_t. There's no reason it needs to be 'long' and making it atomic and using atomic_read_acquire() and atomic_fetch_inc_release() will provide the necessary memory barriers. Add a "woken" flag to tracing_buffers_splice_read() to exit the loop after one more try to fetch data. That is, if it waited for data and something woke it up, it should try to collect any new data and then exit back to user space. Link: https://lore.kernel.org/linux-trace-kernel/CAHk-=wgsNgewHFxZAJiAQznwPMqEtQm… Cc: stable(a)vger.kernel.org Fixes: f3ddb74ad0790 ("tracing: Wake up ring buffer waiters on closing of the file") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- include/linux/ring_buffer.h | 3 ++- include/linux/trace_events.h | 5 ++++- kernel/trace/ring_buffer.c | 11 ++++----- kernel/trace/trace.c | 43 ++++++++++++++++++++++++++---------- 4 files changed, 43 insertions(+), 19 deletions(-) diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index 338a33db1577..dc5ae4e96aee 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -99,7 +99,8 @@ __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *k }) typedef bool (*ring_buffer_cond_fn)(void *data); -int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full); +int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full, + ring_buffer_cond_fn cond, void *data); __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, struct file *filp, poll_table *poll_table, int full); void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu); diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index d68ff9b1247f..fc6d0af56bb1 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -103,13 +103,16 @@ struct trace_iterator { unsigned int temp_size; char *fmt; /* modified format holder */ unsigned int fmt_size; - long wait_index; + atomic_t wait_index; /* trace_seq for __print_flags() and __print_symbolic() etc. */ struct trace_seq tmp_seq; cpumask_var_t started; + /* Set when the file is closed to prevent new waiters */ + bool closed; + /* it's true when current open file is snapshot */ bool snapshot; diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index c198ba466853..81a5303bdc09 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -906,18 +906,19 @@ static bool rb_wait_once(void *data) * as data is added to any of the @buffer's cpu buffers. Otherwise * it will wait for data to be added to a specific cpu buffer. */ -int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full) +int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full, + ring_buffer_cond_fn cond, void *data) { struct ring_buffer_per_cpu *cpu_buffer; struct wait_queue_head *waitq; - ring_buffer_cond_fn cond; struct rb_irq_work *rbwork; - void *data; long once = 0; int ret = 0; - cond = rb_wait_once; - data = &once; + if (!cond) { + cond = rb_wait_once; + data = &once; + } /* * Depending on what the caller is waiting for, either any diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c9c898307348..d390fea3a6a5 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1955,15 +1955,36 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) #endif /* CONFIG_TRACER_MAX_TRACE */ +struct pipe_wait { + struct trace_iterator *iter; + int wait_index; +}; + +static bool wait_pipe_cond(void *data) +{ + struct pipe_wait *pwait = data; + struct trace_iterator *iter = pwait->iter; + + if (atomic_read_acquire(&iter->wait_index) != pwait->wait_index) + return true; + + return iter->closed; +} + static int wait_on_pipe(struct trace_iterator *iter, int full) { + struct pipe_wait pwait; int ret; /* Iterators are static, they should be filled or empty */ if (trace_buffer_iter(iter, iter->cpu_file)) return 0; - ret = ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file, full); + pwait.wait_index = atomic_read_acquire(&iter->wait_index); + pwait.iter = iter; + + ret = ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file, full, + wait_pipe_cond, &pwait); #ifdef CONFIG_TRACER_MAX_TRACE /* @@ -8398,9 +8419,9 @@ static int tracing_buffers_flush(struct file *file, fl_owner_t id) struct ftrace_buffer_info *info = file->private_data; struct trace_iterator *iter = &info->iter; - iter->wait_index++; + iter->closed = true; /* Make sure the waiters see the new wait_index */ - smp_wmb(); + (void)atomic_fetch_inc_release(&iter->wait_index); ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file); @@ -8500,6 +8521,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, .spd_release = buffer_spd_release, }; struct buffer_ref *ref; + bool woken = false; int page_size; int entries, i; ssize_t ret = 0; @@ -8573,17 +8595,17 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, /* did we read anything? */ if (!spd.nr_pages) { - long wait_index; if (ret) goto out; + if (woken) + goto out; + ret = -EAGAIN; if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) goto out; - wait_index = READ_ONCE(iter->wait_index); - ret = wait_on_pipe(iter, iter->snapshot ? 0 : iter->tr->buffer_percent); if (ret) goto out; @@ -8592,10 +8614,8 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, if (!tracer_tracing_is_on(iter->tr)) goto out; - /* Make sure we see the new wait_index */ - smp_rmb(); - if (wait_index != iter->wait_index) - goto out; + /* Iterate one more time to collect any new data then exit */ + woken = true; goto again; } @@ -8618,9 +8638,8 @@ static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned mutex_lock(&trace_types_lock); - iter->wait_index++; /* Make sure the waiters see the new wait_index */ - smp_wmb(); + (void)atomic_fetch_inc_release(&iter->wait_index); ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file); -- 2.43.0

9 months, 3 weeks

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[PATCH v3 1/2] ring-buffer: Use wait_event_interruptible() in ring_buffer_wait()

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Convert ring_buffer_wait() over to wait_event_interruptible(). The default condition is to execute the wait loop inside __wait_event() just once. This does not change the ring_buffer_wait() prototype yet, but restructures the code so that it can take a "cond" and "data" parameter and will call wait_event_interruptible() with a helper function as the condition. The helper function (rb_wait_cond) takes the cond function and data parameters. It will first check if the buffer hit the watermark defined by the "full" parameter and then call the passed in condition parameter. If either are true, it returns true. If rb_wait_cond() does not return true, it will set the appropriate "waiters_pending" flag and returns false. Link: https://lore.kernel.org/linux-trace-kernel/CAHk-=wgsNgewHFxZAJiAQznwPMqEtQm… Cc: stable(a)vger.kernel.org Fixes: f3ddb74ad0790 ("tracing: Wake up ring buffer waiters on closing of the file") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- include/linux/ring_buffer.h | 1 + kernel/trace/ring_buffer.c | 116 +++++++++++++++++++++--------------- 2 files changed, 69 insertions(+), 48 deletions(-) diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index fa802db216f9..338a33db1577 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -98,6 +98,7 @@ __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *k __ring_buffer_alloc((size), (flags), &__key); \ }) +typedef bool (*ring_buffer_cond_fn)(void *data); int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full); __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, struct file *filp, poll_table *poll_table, int full); diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 6ef763f57c66..c198ba466853 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -842,43 +842,15 @@ static bool rb_watermark_hit(struct trace_buffer *buffer, int cpu, int full) return ret; } -/** - * ring_buffer_wait - wait for input to the ring buffer - * @buffer: buffer to wait on - * @cpu: the cpu buffer to wait on - * @full: wait until the percentage of pages are available, if @cpu != RING_BUFFER_ALL_CPUS - * - * If @cpu == RING_BUFFER_ALL_CPUS then the task will wake up as soon - * as data is added to any of the @buffer's cpu buffers. Otherwise - * it will wait for data to be added to a specific cpu buffer. - */ -int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full) +static inline bool +rb_wait_cond(struct rb_irq_work *rbwork, struct trace_buffer *buffer, + int cpu, int full, ring_buffer_cond_fn cond, void *data) { - struct ring_buffer_per_cpu *cpu_buffer; - DEFINE_WAIT(wait); - struct rb_irq_work *work; - int ret = 0; - - /* - * Depending on what the caller is waiting for, either any - * data in any cpu buffer, or a specific buffer, put the - * caller on the appropriate wait queue. - */ - if (cpu == RING_BUFFER_ALL_CPUS) { - work = &buffer->irq_work; - /* Full only makes sense on per cpu reads */ - full = 0; - } else { - if (!cpumask_test_cpu(cpu, buffer->cpumask)) - return -ENODEV; - cpu_buffer = buffer->buffers[cpu]; - work = &cpu_buffer->irq_work; - } + if (rb_watermark_hit(buffer, cpu, full)) + return true; - if (full) - prepare_to_wait(&work->full_waiters, &wait, TASK_INTERRUPTIBLE); - else - prepare_to_wait(&work->waiters, &wait, TASK_INTERRUPTIBLE); + if (cond(data)) + return true; /* * The events can happen in critical sections where @@ -901,27 +873,75 @@ int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full) * a task has been queued. It's OK for spurious wake ups. */ if (full) - work->full_waiters_pending = true; + rbwork->full_waiters_pending = true; else - work->waiters_pending = true; + rbwork->waiters_pending = true; - if (rb_watermark_hit(buffer, cpu, full)) - goto out; + return false; +} - if (signal_pending(current)) { - ret = -EINTR; - goto out; +/* + * The default wait condition for ring_buffer_wait() is to just to exit the + * wait loop the first time it is woken up. + */ +static bool rb_wait_once(void *data) +{ + long *once = data; + + /* wait_event() actually calls this twice before scheduling*/ + if (*once > 1) + return true; + + (*once)++; + return false; +} + +/** + * ring_buffer_wait - wait for input to the ring buffer + * @buffer: buffer to wait on + * @cpu: the cpu buffer to wait on + * @full: wait until the percentage of pages are available, if @cpu != RING_BUFFER_ALL_CPUS + * + * If @cpu == RING_BUFFER_ALL_CPUS then the task will wake up as soon + * as data is added to any of the @buffer's cpu buffers. Otherwise + * it will wait for data to be added to a specific cpu buffer. + */ +int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full) +{ + struct ring_buffer_per_cpu *cpu_buffer; + struct wait_queue_head *waitq; + ring_buffer_cond_fn cond; + struct rb_irq_work *rbwork; + void *data; + long once = 0; + int ret = 0; + + cond = rb_wait_once; + data = &once; + + /* + * Depending on what the caller is waiting for, either any + * data in any cpu buffer, or a specific buffer, put the + * caller on the appropriate wait queue. + */ + if (cpu == RING_BUFFER_ALL_CPUS) { + rbwork = &buffer->irq_work; + /* Full only makes sense on per cpu reads */ + full = 0; + } else { + if (!cpumask_test_cpu(cpu, buffer->cpumask)) + return -ENODEV; + cpu_buffer = buffer->buffers[cpu]; + rbwork = &cpu_buffer->irq_work; } - schedule(); - out: if (full) - finish_wait(&work->full_waiters, &wait); + waitq = &rbwork->full_waiters; else - finish_wait(&work->waiters, &wait); + waitq = &rbwork->waiters; - if (!ret && !rb_watermark_hit(buffer, cpu, full) && signal_pending(current)) - ret = -EINTR; + ret = wait_event_interruptible((*waitq), + rb_wait_cond(rbwork, buffer, cpu, full, cond, data)); return ret; } -- 2.43.0

9 months, 3 weeks

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[PATCH 1/2] ring-buffer: Fix full_waiters_pending in poll

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> If a reader of the ring buffer is doing a poll, and waiting for the ring buffer to hit a specific watermark, there could be a case where it gets into an infinite ping-pong loop. The poll code has: rbwork->full_waiters_pending = true; if (!cpu_buffer->shortest_full || cpu_buffer->shortest_full > full) cpu_buffer->shortest_full = full; The writer will see full_waiters_pending and check if the ring buffer is filled over the percentage of the shortest_full value. If it is, it calls an irq_work to wake up all the waiters. But the code could get into a circular loop: CPU 0 CPU 1 ----- ----- [ Poll ] [ shortest_full = 0 ] rbwork->full_waiters_pending = true; if (rbwork->full_waiters_pending && [ buffer percent ] > shortest_full) { rbwork->wakeup_full = true; [ queue_irqwork ] cpu_buffer->shortest_full = full; [ IRQ work ] if (rbwork->wakeup_full) { cpu_buffer->shortest_full = 0; wakeup poll waiters; [woken] if ([ buffer percent ] > full) break; rbwork->full_waiters_pending = true; if (rbwork->full_waiters_pending && [ buffer percent ] > shortest_full) { rbwork->wakeup_full = true; [ queue_irqwork ] cpu_buffer->shortest_full = full; [ IRQ work ] if (rbwork->wakeup_full) { cpu_buffer->shortest_full = 0; wakeup poll waiters; [woken] [ Wash, rinse, repeat! ] In the poll, the shortest_full needs to be set before the full_pending_waiters, as once that is set, the writer will compare the current shortest_full (which is incorrect) to decide to call the irq_work, which will reset the shortest_full (expecting the readers to update it). Also move the setting of full_waiters_pending after the check if the ring buffer has the required percentage filled. There's no reason to tell the writer to wake up waiters if there are no waiters. Cc: stable(a)vger.kernel.org Fixes: 42fb0a1e84ff5 ("tracing/ring-buffer: Have polling block on watermark") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/ring_buffer.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index aa332ace108b..adfe603a769b 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -964,16 +964,32 @@ __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, poll_wait(filp, &rbwork->full_waiters, poll_table); raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags); - rbwork->full_waiters_pending = true; if (!cpu_buffer->shortest_full || cpu_buffer->shortest_full > full) cpu_buffer->shortest_full = full; raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags); - } else { - poll_wait(filp, &rbwork->waiters, poll_table); - rbwork->waiters_pending = true; + if (full_hit(buffer, cpu, full)) + return EPOLLIN | EPOLLRDNORM; + /* + * Only allow full_waiters_pending update to be seen after + * the shortest_full is set. If the writer sees the + * full_waiters_pending flag set, it will compare the + * amount in the ring buffer to shortest_full. If the amount + * in the ring buffer is greater than the shortest_full + * percent, it will call the irq_work handler to wake up + * this list. The irq_handler will reset shortest_full + * back to zero. That's done under the reader_lock, but + * the below smp_mb() makes sure that the update to + * full_waiters_pending doesn't leak up into the above. + */ + smp_mb(); + rbwork->full_waiters_pending = true; + return 0; } + poll_wait(filp, &rbwork->waiters, poll_table); + rbwork->waiters_pending = true; + /* * There's a tight race between setting the waiters_pending and * checking if the ring buffer is empty. Once the waiters_pending bit @@ -989,9 +1005,6 @@ __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, */ smp_mb(); - if (full) - return full_hit(buffer, cpu, full) ? EPOLLIN | EPOLLRDNORM : 0; - if ((cpu == RING_BUFFER_ALL_CPUS && !ring_buffer_empty(buffer)) || (cpu != RING_BUFFER_ALL_CPUS && !ring_buffer_empty_cpu(buffer, cpu))) return EPOLLIN | EPOLLRDNORM; -- 2.43.0

9 months, 3 weeks

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[PATCH v1] usb: typec: tcpm: Update PD of Type-C port upon pd_set

by Kyle Tso

The PD of Type-C port needs to be updated in pd_set. Unlink the Type-C port device to the old PD before linking it to a new one. Fixes: cd099cde4ed2 ("usb: typec: tcpm: Support multiple capabilities") Cc: stable(a)vger.kernel.org Signed-off-by: Kyle Tso <kyletso(a)google.com> --- drivers/usb/typec/tcpm/tcpm.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index 3d505614bff1..896f594b9328 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -6907,7 +6907,9 @@ static int tcpm_pd_set(struct typec_port *p, struct usb_power_delivery *pd) port->port_source_caps = data->source_cap; port->port_sink_caps = data->sink_cap; + typec_port_set_usb_power_delivery(p, NULL); port->selected_pd = pd; + typec_port_set_usb_power_delivery(p, port->selected_pd); unlock: mutex_unlock(&port->lock); return ret; -- 2.44.0.278.ge034bb2e1d-goog

9 months, 3 weeks

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[PATCH v1] usb: typec: tcpm: Correct port source pdo array in pd_set callback

by Kyle Tso

In tcpm_pd_set, the array of port source capabilities is port->src_pdo, not port->snk_pdo. Fixes: cd099cde4ed2 ("usb: typec: tcpm: Support multiple capabilities") Cc: stable(a)vger.kernel.org Signed-off-by: Kyle Tso <kyletso(a)google.com> --- drivers/usb/typec/tcpm/tcpm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index 3d505614bff1..9485f6373de4 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -6858,7 +6858,7 @@ static int tcpm_pd_set(struct typec_port *p, struct usb_power_delivery *pd) if (data->source_desc.pdo[0]) { for (i = 0; i < PDO_MAX_OBJECTS && data->source_desc.pdo[i]; i++) - port->snk_pdo[i] = data->source_desc.pdo[i]; + port->src_pdo[i] = data->source_desc.pdo[i]; port->nr_src_pdo = i + 1; } -- 2.44.0.278.ge034bb2e1d-goog

9 months, 3 weeks

2
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[PATCH 2/2] tracing: Remove unnecessary var destroy in onmax_destroy()

by George Guo

From: George Guo <guodongtai(a)kylinos.cn> The onmax_destroy() destroyed the onmax var, casusing a double-free error flagged by KASAN. This is tested via "./ftracetest test.d/trigger/inter-event/ trigger-onmatch-onmax-action-hist.tc". ================================================================== BUG: KASAN: use-after-free in destroy_hist_field+0x1c2/0x200 Read of size 8 at addr ffff88800a4ad100 by task ftracetest/4731 CPU: 0 PID: 4731 Comm: ftracetest Kdump: loaded Tainted: GE 4.19.90-89 #77 Source Version: Unknown Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0 Call Trace: dump_stack+0xcb/0x10b print_address_description.cold+0x54/0x249 kasan_report_error.cold+0x63/0xab ? destroy_hist_field+0x1c2/0x200 ? hist_trigger_elt_data_alloc+0x5a0/0x5a0 __asan_report_load8_noabort+0x8d/0xa0 ? destroy_hist_field+0x1c2/0x200 destroy_hist_field+0x1c2/0x200 onmax_destroy+0x72/0x1e0 ? hist_trigger_elt_data_alloc+0x5a0/0x5a0 destroy_hist_data+0x236/0xa40 event_hist_trigger_free+0x212/0x2f0 ? update_cond_flag+0x128/0x170 ? event_hist_trigger_func+0x2880/0x2880 hist_unregister_trigger+0x2f2/0x4f0 event_hist_trigger_func+0x168c/0x2880 ? tracing_map_cmp_u64+0xa0/0xa0 ? onmatch_create.constprop.0+0xf50/0xf50 ? __mutex_lock_slowpath+0x10/0x10 event_trigger_write+0x2f4/0x490 ? trigger_start+0x180/0x180 ? __fget_light+0x369/0x5d0 ? count_memcg_event_mm+0x104/0x2b0 ? trigger_start+0x180/0x180 __vfs_write+0x81/0x100 vfs_write+0x1e1/0x540 ksys_write+0x12a/0x290 ? __ia32_sys_read+0xb0/0xb0 ? __close_fd+0x1d3/0x280 do_syscall_64+0xe3/0x2d0 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7fd7f4c44e04 Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 48 8d 05 39 34 0c 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 41 54 55 49 89 d4 53 48 89 f5 RSP: 002b:00007fff10370df8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000010f RCX: 00007fd7f4c44e04 RDX: 000000000000010f RSI: 000055fa765df650 RDI: 0000000000000001 RBP: 000055fa765df650 R08: 000000000000000a R09: 0000000000000000 R10: 000000000000000a R11: 0000000000000246 R12: 00007fd7f4d035c0 R13: 000000000000010f R14: 00007fd7f4d037c0 R15: 000000000000010f ================================================================== So remove the onmax_destroy() destroy_hist_field() call for that var. Fixes: 50450603ec9c("tracing: Add 'onmax' hist trigger action support") Cc: stable(a)vger.kernel.org Signed-off-by: George Guo <guodongtai(a)kylinos.cn> --- kernel/trace/trace_events_hist.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 7dcb96305e56..58b8a2575b8c 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -337,7 +337,6 @@ struct action_data { char *fn_name; unsigned int max_var_ref_idx; struct hist_field *max_var; - struct hist_field *var; } onmax; }; }; @@ -3489,7 +3488,6 @@ static void onmax_destroy(struct action_data *data) unsigned int i; destroy_hist_field(data->onmax.max_var, 0); - destroy_hist_field(data->onmax.var, 0); kfree(data->onmax.var_str); kfree(data->onmax.fn_name); @@ -3528,8 +3526,6 @@ static int onmax_create(struct hist_trigger_data *hist_data, if (!ref_field) return -ENOMEM; - data->onmax.var = ref_field; - data->fn = onmax_save; data->onmax.max_var_ref_idx = var_ref_idx; max_var = create_var(hist_data, file, "max", sizeof(u64), "u64"); -- 2.34.1

9 months, 3 weeks

1
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[PATCH 1/2] tracing: Remove unnecessary hist_data destroy in destroy_synth_var_refs()

by George Guo

From: George Guo <guodongtai(a)kylinos.cn> The destroy_synth_var_refs() destroyed hist_data, casusing a double-free error flagged by KASAN. This is tested via "./ftracetest test.d/trigger/inter-event/ trigger-field-variable-support.tc" ================================================================== BUG: KASAN: use-after-free in destroy_hist_field+0x115/0x140 Read of size 4 at addr ffff888012e95318 by task ftracetest/1858 CPU: 1 PID: 1858 Comm: ftracetest Kdump: loaded Tainted: GE 4.19.90-89 #24 Source Version: Unknown Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0 Call Trace: dump_stack+0xcb/0x10b print_address_description.cold+0x54/0x249 kasan_report_error.cold+0x63/0xab ? destroy_hist_field+0x115/0x140 __asan_report_load4_noabort+0x8d/0xa0 ? destroy_hist_field+0x115/0x140 destroy_hist_field+0x115/0x140 destroy_hist_data+0x4e4/0x9a0 event_hist_trigger_free+0x212/0x2f0 ? update_cond_flag+0x128/0x170 ? event_hist_trigger_func+0x2880/0x2880 hist_unregister_trigger+0x2f2/0x4f0 event_hist_trigger_func+0x168c/0x2880 ? tracing_map_read_var_once+0xd0/0xd0 ? create_key_field+0x520/0x520 ? __mutex_lock_slowpath+0x10/0x10 event_trigger_write+0x2f4/0x490 ? trigger_start+0x180/0x180 ? __fget_light+0x369/0x5d0 ? count_memcg_event_mm+0x104/0x2b0 ? trigger_start+0x180/0x180 __vfs_write+0x81/0x100 vfs_write+0x1e1/0x540 ksys_write+0x12a/0x290 ? __ia32_sys_read+0xb0/0xb0 ? __close_fd+0x1d3/0x280 do_syscall_64+0xe3/0x2d0 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 RIP: 0033:0x7efdd342ee04 Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 48 8d 05 39 34 0c 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 41 54 55 49 89 d4 53 48 89 f5 RSP: 002b:00007ffda01f5e08 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000000000b4 RCX: 00007efdd342ee04 RDX: 00000000000000b4 RSI: 000055c5b41b1e90 RDI: 0000000000000001 RBP: 000055c5b41b1e90 R08: 000000000000000a R09: 0000000000000000 R10: 000000000000000a R11: 0000000000000246 R12: 00007efdd34ed5c0 R13: 00000000000000b4 R14: 00007efdd34ed7c0 R15: 00000000000000b4 ================================================================== So remove the destroy_synth_var_refs() call for that hist_data. Fixes: c282a386a397("tracing: Add 'onmatch' hist trigger action support") Cc: stable(a)vger.kernel.org Signed-off-by: George Guo <guodongtai(a)kylinos.cn> --- kernel/trace/trace_events_hist.c | 23 ++--------------------- 1 file changed, 2 insertions(+), 21 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index e004daf8cad5..7dcb96305e56 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -280,8 +280,6 @@ struct hist_trigger_data { struct action_data *actions[HIST_ACTIONS_MAX]; unsigned int n_actions; - struct hist_field *synth_var_refs[SYNTH_FIELDS_MAX]; - unsigned int n_synth_var_refs; struct field_var *field_vars[SYNTH_FIELDS_MAX]; unsigned int n_field_vars; unsigned int n_field_var_str; @@ -1363,8 +1361,8 @@ static struct hist_field *find_var_ref(struct hist_trigger_data *hist_data, return found; } - for (i = 0; i < hist_data->n_synth_var_refs; i++) { - hist_field = hist_data->synth_var_refs[i]; + for (i = 0; i < hist_data->n_var_refs; i++) { + hist_field = hist_data->var_refs[i]; found = check_field_for_var_refs(hist_data, hist_field, var_data, var_idx, 0); if (found) @@ -3707,21 +3705,6 @@ static void save_field_var(struct hist_trigger_data *hist_data, hist_data->n_field_var_str++; } - -static void destroy_synth_var_refs(struct hist_trigger_data *hist_data) -{ - unsigned int i; - - for (i = 0; i < hist_data->n_synth_var_refs; i++) - destroy_hist_field(hist_data->synth_var_refs[i], 0); -} - -static void save_synth_var_ref(struct hist_trigger_data *hist_data, - struct hist_field *var_ref) -{ - hist_data->synth_var_refs[hist_data->n_synth_var_refs++] = var_ref; -} - static int check_synth_field(struct synth_event *event, struct hist_field *hist_field, unsigned int field_pos) @@ -3884,7 +3867,6 @@ static int onmatch_create(struct hist_trigger_data *hist_data, goto err; } - save_synth_var_ref(hist_data, var_ref); field_pos++; kfree(p); continue; @@ -4631,7 +4613,6 @@ static void destroy_hist_data(struct hist_trigger_data *hist_data) destroy_actions(hist_data); destroy_field_vars(hist_data); destroy_field_var_hists(hist_data); - destroy_synth_var_refs(hist_data); kfree(hist_data); } -- 2.34.1

9 months, 3 weeks

1
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[PATCH 41/43] drm/amd/display: fix a bug to dereference already freed old current state memory

by Wayne Lin

From: Wenjing Liu <wenjing.liu(a)amd.com> [why] During minimal transition commit, the base state could be freed if it is current state. This is because after committing minimal transition state, the current state will be swapped to the minimal transition state and the old current state will be released. the release could cause the old current state's memory to be freed. However dc will derefernce this memory when release minimal transition state. Therefore, we need to retain the old current state until we release minimal transition state. Cc: Mario Limonciello <mario.limonciello(a)amd.com> Cc: Alex Deucher <alexander.deucher(a)amd.com> Cc: stable(a)vger.kernel.org Reviewed-by: Josip Pavic <josip.pavic(a)amd.com> Acked-by: Wayne Lin <wayne.lin(a)amd.com> Signed-off-by: Wenjing Liu <wenjing.liu(a)amd.com> --- drivers/gpu/drm/amd/display/dc/core/dc.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c index a372c4965adf..ab0c920333be 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c @@ -4203,7 +4203,6 @@ static void release_minimal_transition_state(struct dc *dc, { restore_minimal_pipe_split_policy(dc, base_context, policy); dc_state_release(minimal_transition_context); - /* restore previous pipe split and odm policy */ } static void force_vsync_flip_in_minimal_transition_context(struct dc_state *context) @@ -4258,7 +4257,7 @@ static bool is_pipe_topology_transition_seamless_with_intermediate_step( intermediate_state, final_state); } -static void swap_and_free_current_context(struct dc *dc, +static void swap_and_release_current_context(struct dc *dc, struct dc_state *new_context, struct dc_stream_state *stream) { @@ -4321,7 +4320,7 @@ static bool commit_minimal_transition_based_on_new_context(struct dc *dc, commit_planes_for_stream(dc, srf_updates, surface_count, stream, NULL, UPDATE_TYPE_FULL, intermediate_context); - swap_and_free_current_context( + swap_and_release_current_context( dc, intermediate_context, stream); dc_state_retain(dc->current_state); success = true; @@ -4338,6 +4337,7 @@ static bool commit_minimal_transition_based_on_current_context(struct dc *dc, bool success = false; struct pipe_split_policy_backup policy; struct dc_state *intermediate_context; + struct dc_state *old_current_state = dc->current_state; struct dc_surface_update srf_updates[MAX_SURFACE_NUM]; int surface_count; @@ -4353,8 +4353,10 @@ static bool commit_minimal_transition_based_on_current_context(struct dc *dc, * with the current state. */ restore_planes_and_stream_state(&dc->scratch.current_state, stream); + dc_state_retain(old_current_state); intermediate_context = create_minimal_transition_state(dc, - dc->current_state, &policy); + old_current_state, &policy); + if (intermediate_context) { if (is_pipe_topology_transition_seamless_with_intermediate_step( dc, @@ -4367,14 +4369,15 @@ static bool commit_minimal_transition_based_on_current_context(struct dc *dc, commit_planes_for_stream(dc, srf_updates, surface_count, stream, NULL, UPDATE_TYPE_FULL, intermediate_context); - swap_and_free_current_context( + swap_and_release_current_context( dc, intermediate_context, stream); dc_state_retain(dc->current_state); success = true; } release_minimal_transition_state(dc, intermediate_context, - dc->current_state, &policy); + old_current_state, &policy); } + dc_state_release(old_current_state); /* * Restore stream and plane states back to the values associated with * new context. @@ -4496,12 +4499,14 @@ static bool commit_minimal_transition_state(struct dc *dc, dc->debug.pipe_split_policy != MPC_SPLIT_AVOID ? "MPC in Use" : "Unknown"); + dc_state_retain(transition_base_context); transition_context = create_minimal_transition_state(dc, transition_base_context, &policy); if (transition_context) { ret = dc_commit_state_no_check(dc, transition_context); release_minimal_transition_state(dc, transition_context, transition_base_context, &policy); } + dc_state_release(transition_base_context); if (ret != DC_OK) { /* this should never happen */ @@ -4839,7 +4844,7 @@ static bool update_planes_and_stream_v2(struct dc *dc, context); } if (dc->current_state != context) - swap_and_free_current_context(dc, context, stream); + swap_and_release_current_context(dc, context, stream); return true; } @@ -4941,7 +4946,7 @@ static bool update_planes_and_stream_v3(struct dc *dc, commit_planes_and_stream_update_with_new_context(dc, srf_updates, surface_count, stream, stream_update, update_type, new_context); - swap_and_free_current_context(dc, new_context, stream); + swap_and_release_current_context(dc, new_context, stream); } return true; -- 2.37.3

9 months, 3 weeks

1
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[PATCH 33/43] drm/amd/display: Prevent crash on bring-up

by Wayne Lin

From: Chris Park <chris.park(a)amd.com> [Why] Disabling stream encoder invokes a function that no longer exists in bring-up. [How] Check if the function declaration is NULL in disable stream encoder. Cc: Mario Limonciello <mario.limonciello(a)amd.com> Cc: Alex Deucher <alexander.deucher(a)amd.com> Cc: stable(a)vger.kernel.org Reviewed-by: Charlene Liu <charlene.liu(a)amd.com> Acked-by: Wayne Lin <wayne.lin(a)amd.com> Signed-off-by: Chris Park <chris.park(a)amd.com> --- drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c index 9d5df4c0da59..0ba1feaf96c0 100644 --- a/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c +++ b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c @@ -1185,7 +1185,8 @@ void dce110_disable_stream(struct pipe_ctx *pipe_ctx) if (dccg) { dccg->funcs->disable_symclk32_se(dccg, dp_hpo_inst); dccg->funcs->set_dpstreamclk(dccg, REFCLK, tg->inst, dp_hpo_inst); - dccg->funcs->set_dtbclk_dto(dccg, &dto_params); + if (dccg && dccg->funcs->set_dtbclk_dto) + dccg->funcs->set_dtbclk_dto(dccg, &dto_params); } } else if (dccg && dccg->funcs->disable_symclk_se) { dccg->funcs->disable_symclk_se(dccg, stream_enc->stream_enc_inst, -- 2.37.3

9 months, 3 weeks

1
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