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 605CE35C1B6; Fri, 9 Jan 2026 12:49:52 +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=1767962992; cv=none; b=OlOhvotpRWa5gYfl39FC4cMwWKzgwkdBGSDQq7RQ4Hj+29C/EuKpfgmzkMnAbnstolMXV+BJlAKZh86yPj1wXG+zvd4cSyqAXJf2Ip6ApXN83prQ6FOii+qmeG9SlzC6CCuARZCuex0+g5Vcd9YtFAvMouFnCeaSSNdKZrIWdFM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767962992; c=relaxed/simple; bh=JUD5bUOPNLUkTZ22CtgkgZoknJEZW21/35NOMdS0dWI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=i9tDHEvwVKnJ/8PuqiwAd1OJLgI+UqYXkMVjEQ81xtKveH7ayVUTCQxDSgypHpK6Jxz9pWffevV+0QD8/eXBFZ0DmvFfGCdVNIap+ZAAnWMMngpwZUDuroVZE/NMst0ImX9SUwNa+ZOspNfT664q270oTXTc4GGJlVFf6oipNpk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NDsv1xZW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="NDsv1xZW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E219EC4CEF1; Fri, 9 Jan 2026 12:49:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767962992; bh=JUD5bUOPNLUkTZ22CtgkgZoknJEZW21/35NOMdS0dWI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NDsv1xZWVupmVh3DE2ECmiWC9eCgIrXO8fmRAeYgjU7W/eqwGkEFYcgrcBvXClSTN l+Ehx2n9HeMGqZfTDU2u53Co3iMaFd11W0HaBJ8iYgvROATCEIeqlRF/iC38/fF6yM liEni/kZQ6fAhn5wCgfDug6ta3sqhi8QSYzMZCAs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Baokun Li , David Howells , Christian Brauner , Chen Yu Subject: [PATCH 6.1 527/634] fscache: delete fscache_cookie_lru_timer when fscache exits to avoid UAF Date: Fri, 9 Jan 2026 12:43:25 +0100 Message-ID: <20260109112137.396227194@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260109112117.407257400@linuxfoundation.org> References: <20260109112117.407257400@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li commit 72a6e22c604c95ddb3b10b5d3bb85b6ff4dbc34f upstream. The fscache_cookie_lru_timer is initialized when the fscache module is inserted, but is not deleted when the fscache module is removed. If timer_reduce() is called before removing the fscache module, the fscache_cookie_lru_timer will be added to the timer list of the current cpu. Afterwards, a use-after-free will be triggered in the softIRQ after removing the fscache module, as follows: ================================================================== BUG: unable to handle page fault for address: fffffbfff803c9e9 PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page PGD 21ffea067 P4D 21ffea067 PUD 21ffe6067 PMD 110a7c067 PTE 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G W 6.11.0-rc3 #855 Tainted: [W]=WARN RIP: 0010:__run_timer_base.part.0+0x254/0x8a0 Call Trace: tmigr_handle_remote_up+0x627/0x810 __walk_groups.isra.0+0x47/0x140 tmigr_handle_remote+0x1fa/0x2f0 handle_softirqs+0x180/0x590 irq_exit_rcu+0x84/0xb0 sysvec_apic_timer_interrupt+0x6e/0x90 asm_sysvec_apic_timer_interrupt+0x1a/0x20 RIP: 0010:default_idle+0xf/0x20 default_idle_call+0x38/0x60 do_idle+0x2b5/0x300 cpu_startup_entry+0x54/0x60 start_secondary+0x20d/0x280 common_startup_64+0x13e/0x148 Modules linked in: [last unloaded: netfs] ================================================================== Therefore delete fscache_cookie_lru_timer when removing the fscahe module. Fixes: 12bb21a29c19 ("fscache: Implement cookie user counting and resource pinning") Cc: stable@kernel.org Signed-off-by: Baokun Li Link: https://lore.kernel.org/r/20240826112056.2458299-1-libaokun@huaweicloud.com Acked-by: David Howells Signed-off-by: Christian Brauner [ Changed the file path due to missing commit:47757ea83a54 ("netfs, fscache: Move fs/fscache/* into fs/netfs/") ] Signed-off-by: Chen Yu Signed-off-by: Greg Kroah-Hartman --- fs/fscache/main.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/fscache/main.c +++ b/fs/fscache/main.c @@ -114,6 +114,7 @@ static void __exit fscache_exit(void) kmem_cache_destroy(fscache_cookie_jar); fscache_proc_cleanup(); + timer_shutdown_sync(&fscache_cookie_lru_timer); destroy_workqueue(fscache_wq); pr_notice("Unloaded\n"); }