On Tue, 27 Sep 2022 11:28:13 -0400
Waiman Long <longman@xxxxxxxxxx> wrote:
On 9/22/22 10:56, Waiman Long wrote:You may have noticed (from today's emailing) I applied the patch ;-)
It was found that some tracing functions in kernel/trace/trace.c acquirePing!
an arch_spinlock_t with preemption and irqs enabled. An example is the
tracing_saved_cmdlines_size_read() function which intermittently causes
a "BUG: using smp_processor_id() in preemptible" warning when the LTP
read_all_proc test is run.
That can be problematic in case preemption happens after acquiring the
lock. Add the necessary preemption or interrupt disabling code in the
appropriate places before acquiring an arch_spinlock_t.
The convention here is to disable preemption for trace_cmdline_lock and
interupt for max_lock.
Fixes: a35873a0993b ("tracing: Add conditional snapshot")
Fixes: 939c7a4f04fc ("tracing: Introduce saved_cmdlines_size file")
Suggested-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
kernel/trace/trace.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
Any comment on this patch?