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 E200042C290; Sat, 28 Feb 2026 17:46:42 +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=1772300803; cv=none; b=oTu38s3FhbWNxZjmqSQskX9OPY93q4Z47zil0xoDXHr6DYMYj2g0foFDiE9OY8hZ9crD5YLPYOt5xjijrmfyqgzukBCGTUTXcC6QnrfrvnDW49FUSqRjugE9v2eKUd/gN2/ucIAG6hXsfjIuLekyrUdTszBC92sNlYxESfA2/Ao= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300803; c=relaxed/simple; bh=emS6QuFF9VEhdCkIz/+zQpypOAt1iUdrxrOV78XzjHQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=khIwubypNoQn/VsxFOjAZBS2erGzELF/wNCXqS8x4Q8UAm0a0ucUDdfy4oVEcTYQ12RwRk17lIipPLOvR4ZmPVMNrY5MtRM5foRRSMCck9wy4clK0BUiGkJpjGcJ5qFgbX6nRgC0pwernCTCyedlpsby9FsHKVyFFo2yofQI7mA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sqQWy5HA; 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="sqQWy5HA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ECAB1C116D0; Sat, 28 Feb 2026 17:46:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772300802; bh=emS6QuFF9VEhdCkIz/+zQpypOAt1iUdrxrOV78XzjHQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sqQWy5HADR2ubVjlKmiuoQoIQcI0JzecJ6PGhcACZIewIsXYxCBLZsrHqKIFpEUiZ FRk3LhZkNuQBWC835euXMQwsVm8R1RXH6s7aO0SILLHAcCCrewhE6TzclpVBLdlmlo 9qsBBrVXVMEoXhkCbmxtoQVevnwh/oDSmES2GdLls4kx9230dI/jlYafJtG07TEXGs WU9nelDvzvWbhvWXs3aMdikM+ez6LeghVqFURVVVRoWyeN6AvJf2w7fFWiVpI3aA0o amhzJf8C7vc+8GiA5ALEIKOEsNt+XzoCycZOAcDzxfxssoaO8E/l6X1MkWCSlDwvE5 P5esuIjQUIosQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Daniil Dulov , kernel test robot , Dan Carpenter , "Masami Hiramatsu (Google)" , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 6.19 835/844] ring-buffer: Fix possible dereference of uninitialized pointer Date: Sat, 28 Feb 2026 12:32:28 -0500 Message-ID: <20260228173244.1509663-836-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228173244.1509663-1-sashal@kernel.org> References: <20260228173244.1509663-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Daniil Dulov [ Upstream commit f1547779402c4cd67755c33616b7203baa88420b ] 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) Signed-off-by: Sasha Levin --- 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 630221b00838e..ad08430347b06 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1918,6 +1918,8 @@ 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) { @@ -1928,7 +1930,6 @@ 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