tracing: Add NULL checks for buffer in ring_buffer_free_read_page()

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[ Upstream commit 3e4272b995 ]

In a previous commit 7433632c9f, buffer, buffer->buffers and
buffer->buffers[cpu] in ring_buffer_wake_waiters() can be NULL,
and thus the related checks are added.

However, in the same call stack, these variables are also used in
ring_buffer_free_read_page():

tracing_buffers_release()
  ring_buffer_wake_waiters(iter->array_buffer->buffer)
    cpu_buffer = buffer->buffers[cpu] -> Add checks by previous commit
  ring_buffer_free_read_page(iter->array_buffer->buffer)
    cpu_buffer = buffer->buffers[cpu] -> No check

Thus, to avod possible null-pointer derefernces, the related checks
should be added.

These results are reported by a static tool designed by myself.

Link: https://lkml.kernel.org/r/20230113125501.760324-1-baijiaju1990@gmail.com

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Jia-Ju Bai 2023-01-13 20:55:01 +08:00 • committed by Greg Kroah-Hartman

parent 6d2128d2ee

commit e54bb56a01

1 changed files with 6 additions and 1 deletions

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kernel/trace/ring_buffer.c

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