From: Daniil Tatianin Date: Mon, 14 Nov 2022 14:31:29 +0000 (+0300) Subject: ring_buffer: Do not deactivate non-existant pages X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=00f74b1a98a2d0a0067b2a11c13b55821ad73797;p=linux.git ring_buffer: Do not deactivate non-existant pages 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 Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 5e8ae0b3ef712..76c4972b9474c 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1733,9 +1733,9 @@ 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);