| Message ID | 20230906081930.3939106-1-zhengyejian1@huawei.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | f6bd2c92488c30ef53b5bd80c52f0a7eee9d545a |
| Headers | show |
| Series | ring-buffer: Avoid softlockup in ring_buffer_resize() | expand |
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 78502d4c7214..72ccf75defd0 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2198,6 +2198,8 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, err = -ENOMEM; goto out_err; } + + cond_resched(); } cpus_read_lock();
When user resize all trace ring buffer through file 'buffer_size_kb', then in ring_buffer_resize(), kernel allocates buffer pages for each cpu in a loop. If the kernel preemption model is PREEMPT_NONE and there are many cpus and there are many buffer pages to be allocated, it may not give up cpu for a long time and finally cause a softlockup. To avoid it, call cond_resched() after each cpu buffer allocation. Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> --- kernel/trace/ring_buffer.c | 2 ++ 1 file changed, 2 insertions(+)