tracing: Fix race in trace_open and buffer resize call
commitbbeb97464e
upstream. Below race can come, if trace_open and resize of cpu buffer is running parallely on different cpus CPUX CPUY ring_buffer_resize atomic_read(&buffer->resize_disabled) tracing_open tracing_reset_online_cpus ring_buffer_reset_cpu rb_reset_cpu rb_update_pages remove/insert pages resetting pointer This race can cause data abort or some times infinte loop in rb_remove_pages and rb_insert_pages while checking pages for sanity. Take buffer lock to fix this. Link: https://lkml.kernel.org/r/1601976833-24377-1-git-send-email-gkohli@codeaurora.org Cc: stable@vger.kernel.org Fixes:83f40318da
("ring-buffer: Make removal of ring buffer pages atomic") Reported-by: Denis Efremov <efremov@linux.com> Signed-off-by: Gaurav Kohli <gkohli@codeaurora.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
c4a23c852e
commit
b899d5b2a4
|
@ -4448,6 +4448,8 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)
|
|||
|
||||
if (!cpumask_test_cpu(cpu, buffer->cpumask))
|
||||
return;
|
||||
/* prevent another thread from changing buffer sizes */
|
||||
mutex_lock(&buffer->mutex);
|
||||
|
||||
atomic_inc(&buffer->resize_disabled);
|
||||
atomic_inc(&cpu_buffer->record_disabled);
|
||||
|
@ -4471,6 +4473,8 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)
|
|||
|
||||
atomic_dec(&cpu_buffer->record_disabled);
|
||||
atomic_dec(&buffer->resize_disabled);
|
||||
|
||||
mutex_unlock(&buffer->mutex);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(ring_buffer_reset_cpu);
|
||||
|
||||
|
|
Loading…
Reference in New Issue