diff mbox series

[for-linus,09/15] ring-buffer: Avoid softlockup in ring_buffer_resize()

Message ID 20230909032349.854283780@goodmis.org
State New
Headers
Series [for-linus,01/15] tracefs: Add missing lockdown check to tracefs_create_dir() |

Commit Message

Steven Rostedt Sept. 9, 2023, 3:16 a.m. UTC 
  From: Zheng Yejian <zhengyejian1@huawei.com>

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>
---
 kernel/trace/ring_buffer.c | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

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();