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| author | Zheng Yejian <zhengyejian1@huawei.com> | 2023-09-06 16:19:30 +0800 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-09-07 16:38:54 -0400 |
| commit | f6bd2c92488c30ef53b5bd80c52f0a7eee9d545a (patch) | |
| tree | f2b3e26bc8ffbafaa55ed241753fb98d251dabb8 /kernel | |
| parent | e5c624f027ac74f97e97c8f36c69228ac9f1102d (diff) | |
| download | lwn-f6bd2c92488c30ef53b5bd80c52f0a7eee9d545a.tar.gz lwn-f6bd2c92488c30ef53b5bd80c52f0a7eee9d545a.zip | |
ring-buffer: Avoid softlockup in ring_buffer_resize()
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.
Link: https://lore.kernel.org/linux-trace-kernel/20230906081930.3939106-1-zhengyejian1@huawei.com
Cc: <mhiramat@kernel.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/ring_buffer.c | 2 |
1 files changed, 2 insertions, 0 deletions
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(); |