From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A0E830DD1F; Thu, 19 Feb 2026 20:49:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771534198; cv=none; b=sneDiDy5XkfhJifttTnMc0I4G7vFOcYtaPQ9BSxMTvAIZjxiuVc25ZaNvVQFe4kea/f1NJ/yOfyBSIVYiFkZCGx2CWNx8SKE9pBxXJ6MuesASfefR7YMbkB4RX7dzNadx4K1uq8XU1NoqTEF8XJGkWQlKbihnVGCzRnMfbYxsOk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771534198; c=relaxed/simple; bh=05eXMLVb0c51uSNdXRwWQbrKXkkVcDp8J4v23OawnDY=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=ubOweawIMpDjT1a1uc43fKhkfvoxuhraPLoCvVpAUBmlCP4eS/P5kbgT4hUArb+nFyqOsfZJ/Jrp+hDMfCmhHFQm/miWqPxhp7PZxAQm60AAEXJ7HWZ0zoFYJZQsoNbTh5P1eU7HoZ35fwMkvwbiDqMgfG1fzsviAY9NQmkt9Lo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sUFlVw5v; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="sUFlVw5v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EE0BEC116D0; Thu, 19 Feb 2026 20:49:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771534198; bh=05eXMLVb0c51uSNdXRwWQbrKXkkVcDp8J4v23OawnDY=; h=Date:From:To:Cc:Subject:References:From; b=sUFlVw5v2enIhrJexWmwfU6QkyxYfny+hVWdyR/SCwyJ5r6IkLUGPAgv/kNN/z06e O8KbTcyfXKQ/HVWRdt6rKjU391nz0+Dh5BzPnDo2OYhlZUZDkr2tIx9Z7pUGe/4Sh5 dW1j2rOIVkZbmo6ENDXmpOSvZXdMNLdu/vuRVfNgvh8PbpN3qlIEsULceUYNT3JWGp WZeaTLQrNFjbi4SUJgGIetEYzvl/WhOfe/2GALcvaA0Xbl+QLFWhUH8BdD1Ul/L4ud KdHKIH7MNFrZcp3D8KpZGGOf/zjFURPjHDHRHMoHSbwsWDZiKVpNDecTroEoan/X51 exPgr/YftXH5Q== Received: from rostedt by gandalf with local (Exim 4.99.1) (envelope-from ) id 1vtAyK-00000000kfJ-3ZuR; Thu, 19 Feb 2026 15:50:04 -0500 Message-ID: <20260219205004.720044375@kernel.org> User-Agent: quilt/0.69 Date: Thu, 19 Feb 2026 15:49:48 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , stable@vger.kernel.org, kernel test robot , Dan Carpenter , Daniil Dulov Subject: [for-linus][PATCH 1/5] ring-buffer: Fix possible dereference of uninitialized pointer References: <20260219204947.830172370@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Daniil Dulov There is a pointer head_page in rb_meta_validate_events() which is not initialized at the beginning of a function. This pointer can be dereferenced if there is a failure during reader page validation. In this case the control is passed to "invalid" label where the pointer is dereferenced in a loop. To fix the issue initialize orig_head and head_page before calling rb_validate_buffer. Found by Linux Verification Center (linuxtesting.org) with SVACE. Cc: stable@vger.kernel.org Reported-by: kernel test robot Reported-by: Dan Carpenter Acked-by: Masami Hiramatsu (Google) Link: https://patch.msgid.link/20260213100130.2013839-1-d.dulov@aladdin.ru Closes: https://lore.kernel.org/r/202406130130.JtTGRf7W-lkp@intel.com/ Fixes: 5f3b6e839f3c ("ring-buffer: Validate boot range memory events") Signed-off-by: Daniil Dulov Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ring_buffer.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index d33103408955..bdc8010d8f48 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1919,6 +1919,8 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) if (!meta || !meta->head_buffer) return; + orig_head = head_page = cpu_buffer->head_page; + /* Do the reader page first */ ret = rb_validate_buffer(cpu_buffer->reader_page->page, cpu_buffer->cpu); if (ret < 0) { @@ -1929,7 +1931,6 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer) entry_bytes += local_read(&cpu_buffer->reader_page->page->commit); local_set(&cpu_buffer->reader_page->entries, ret); - orig_head = head_page = cpu_buffer->head_page; ts = head_page->page->time_stamp; /* -- 2.51.0