From: Daniil Tatianin d-tatianin@yandex-team.ru
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 --- kernel/trace/ring_buffer.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1769,9 +1769,9 @@ static void rb_free_cpu_buffer(struct ri
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);