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ring_buffer: Do not deactivate non-existant pages

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commit 56f4ca0a79a9f1af98f26c54b9b89ba1f9bcc6bd upstream.

rb_head_page_deactivate() expects cpu_buffer to contain a valid list of
->pages, so verify that the list is actually present before calling it.

Found by Linux Verification Center (linuxtesting.org) with the SVACE
static analysis tool.

Link: https://lkml.kernel.org/r/20221114143129.3534443-1-d-tatianin@yandex-team.ru

Cc: stable@vger.kernel.org
Fixes: 77ae365eca895 ("ring-buffer: make lockless")
Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Daniil Tatianin 2022-11-14 17:31:29 +03:00 committed by Greg Kroah-Hartman
parent f58d687630
commit f2302d65e6
1 changed files with 2 additions and 2 deletions
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4
kernel/trace/ring_buffer.c
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@ -1267,9 +1267,9 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
free_buffer_page(cpu_buffer->reader_page);
rb_head_page_deactivate(cpu_buffer);
if (head) {
rb_head_page_deactivate(cpu_buffer);
list_for_each_entry_safe(bpage, tmp, head, list) {
list_del_init(&bpage->list);
free_buffer_page(bpage);