Re: [PATCH v2] sample-trace-array: Fix sleeping function called from invalid context
On 2020/6/10 0:29, Divya Indi wrote: On 6/9/20 6:51 AM, Kefeng Wang wrote: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/5 1 lock held by swapper/5/0: #0: 80001002bd90 (samples/ftrace/sample-trace-array.c:38){+.-.}-{0:0}, at: call_timer_fn+0x8/0x3e0 CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.7.0+ #8 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: dump_backtrace+0x0/0x1a0 show_stack+0x20/0x30 dump_stack+0xe4/0x150 ___might_sleep+0x160/0x200 __might_sleep+0x58/0x90 __mutex_lock+0x64/0x948 mutex_lock_nested+0x3c/0x58 __ftrace_set_clr_event+0x44/0x88 trace_array_set_clr_event+0x24/0x38 mytimer_handler+0x34/0x40 [sample_trace_array] mutex_lock() will be called in interrupt context, using workqueue to fix it. Fixes: Missing it, will send v3, thanks. Signed-off-by: Kefeng Wang Reviewed-by: Divya Indi
Re: [PATCH v2] sample-trace-array: Fix sleeping function called from invalid context
On 6/9/20 6:51 AM, Kefeng Wang wrote: > BUG: sleeping function called from invalid context at > kernel/locking/mutex.c:935 > in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/5 > 1 lock held by swapper/5/0: > #0: 80001002bd90 (samples/ftrace/sample-trace-array.c:38){+.-.}-{0:0}, > at: call_timer_fn+0x8/0x3e0 > CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.7.0+ #8 > Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 > Call trace: > dump_backtrace+0x0/0x1a0 > show_stack+0x20/0x30 > dump_stack+0xe4/0x150 > ___might_sleep+0x160/0x200 > __might_sleep+0x58/0x90 > __mutex_lock+0x64/0x948 > mutex_lock_nested+0x3c/0x58 > __ftrace_set_clr_event+0x44/0x88 > trace_array_set_clr_event+0x24/0x38 > mytimer_handler+0x34/0x40 [sample_trace_array] > > mutex_lock() will be called in interrupt context, using workqueue to fix it. Fixes: > Signed-off-by: Kefeng Wang Reviewed-by: Divya Indi > --- > v2: > - add include of linux/workqueue.h > - add missing cancel_work_sync() suggested by Divya Indi > > samples/ftrace/sample-trace-array.c | 18 +- > 1 file changed, 13 insertions(+), 5 deletions(-) > > diff --git a/samples/ftrace/sample-trace-array.c > b/samples/ftrace/sample-trace-array.c > index d523450d73eb..9e437f930280 100644 > --- a/samples/ftrace/sample-trace-array.c > +++ b/samples/ftrace/sample-trace-array.c > @@ -6,6 +6,7 @@ > #include > #include > #include > +#include > > /* > * Any file that uses trace points, must include the header. > @@ -20,6 +21,16 @@ struct trace_array *tr; > static void mytimer_handler(struct timer_list *unused); > static struct task_struct *simple_tsk; > > +static void trace_work_fn(struct work_struct *work) > +{ > + /* > + * Disable tracing for event "sample_event". > + */ > + trace_array_set_clr_event(tr, "sample-subsystem", "sample_event", > + false); > +} > +static DECLARE_WORK(trace_work, trace_work_fn); > + > /* > * mytimer: Timer setup to disable tracing for event "sample_event". This > * timer is only for the purposes of the sample module to demonstrate access > of > @@ -29,11 +40,7 @@ static DEFINE_TIMER(mytimer, mytimer_handler); > > static void mytimer_handler(struct timer_list *unused) > { > - /* > - * Disable tracing for event "sample_event". > - */ > - trace_array_set_clr_event(tr, "sample-subsystem", "sample_event", > - false); > + schedule_work(_work); > } > > static void simple_thread_func(int count) > @@ -76,6 +83,7 @@ static int simple_thread(void *arg) > simple_thread_func(count++); > > del_timer(); > + cancel_work_sync(_work); > > /* >* trace_array_put() decrements the reference counter associated with
[PATCH v2] sample-trace-array: Fix sleeping function called from invalid context
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/5 1 lock held by swapper/5/0: #0: 80001002bd90 (samples/ftrace/sample-trace-array.c:38){+.-.}-{0:0}, at: call_timer_fn+0x8/0x3e0 CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.7.0+ #8 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: dump_backtrace+0x0/0x1a0 show_stack+0x20/0x30 dump_stack+0xe4/0x150 ___might_sleep+0x160/0x200 __might_sleep+0x58/0x90 __mutex_lock+0x64/0x948 mutex_lock_nested+0x3c/0x58 __ftrace_set_clr_event+0x44/0x88 trace_array_set_clr_event+0x24/0x38 mytimer_handler+0x34/0x40 [sample_trace_array] mutex_lock() will be called in interrupt context, using workqueue to fix it. Signed-off-by: Kefeng Wang --- v2: - add include of linux/workqueue.h - add missing cancel_work_sync() suggested by Divya Indi samples/ftrace/sample-trace-array.c | 18 +- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/samples/ftrace/sample-trace-array.c b/samples/ftrace/sample-trace-array.c index d523450d73eb..9e437f930280 100644 --- a/samples/ftrace/sample-trace-array.c +++ b/samples/ftrace/sample-trace-array.c @@ -6,6 +6,7 @@ #include #include #include +#include /* * Any file that uses trace points, must include the header. @@ -20,6 +21,16 @@ struct trace_array *tr; static void mytimer_handler(struct timer_list *unused); static struct task_struct *simple_tsk; +static void trace_work_fn(struct work_struct *work) +{ + /* +* Disable tracing for event "sample_event". +*/ + trace_array_set_clr_event(tr, "sample-subsystem", "sample_event", + false); +} +static DECLARE_WORK(trace_work, trace_work_fn); + /* * mytimer: Timer setup to disable tracing for event "sample_event". This * timer is only for the purposes of the sample module to demonstrate access of @@ -29,11 +40,7 @@ static DEFINE_TIMER(mytimer, mytimer_handler); static void mytimer_handler(struct timer_list *unused) { - /* -* Disable tracing for event "sample_event". -*/ - trace_array_set_clr_event(tr, "sample-subsystem", "sample_event", - false); + schedule_work(_work); } static void simple_thread_func(int count) @@ -76,6 +83,7 @@ static int simple_thread(void *arg) simple_thread_func(count++); del_timer(); + cancel_work_sync(_work); /* * trace_array_put() decrements the reference counter associated with -- 2.27.0