From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 9E32A48A2BC; Wed, 23 Sep 2026 14:47:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790174874; cv=none; b=hNNqlJiq1zcUwksAkg5+2GnaY2uc9Ez+8j/Dt/RA+VniJtxiTjKHU6/9OjchPI9dkc02ucTsVvZ8BWnDbpzOEdQlMPR7KaUEDR4Bmm9DBVOwUG8gbjePQjBoJuxXm6PrPfaGRMAxUvMX0JmE2K4+/dxESCxzy2L63/L89rBS+EI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790174874; c=relaxed/simple; bh=EX5ebwjfuS2uFq3kCHQpcys/xDu4GZ3UOCBxrWzYkZ8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sx5deFJhzGSBlh5zih5gxUuKWoE9nErugod3DR0Vuv/4NcwASlk6oxHnWf00ymTSmmTueI2cfZTECHll8IYXOtpiI84bQpoaRks9JuJOY3ujALjaAtIu2zeT38OAEakO+eWl+MAX3jF+CaX85FPLEIJlaLay4NARKMf3AwmG9ug= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=c+AyJ3rj; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="c+AyJ3rj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99E551F000FF; Wed, 23 Sep 2026 14:47:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790174873; bh=cWNB+96ZldweumdF4xZDeOAcl572RtclwEHiE03uR4s=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=c+AyJ3rj3QZjXmjxjU1ayQse0KsSFmDJoZwzJPvoBE8cWyHNDuyBMo/NcGvh3OZGr bL4VMzhl9/o9u2a4BnKOwOPUKFIs9x8tKF6S8YsPb4gZcXkkYoar9XffE6ZJstBShI MbWum4Ex9GH1ATg/Iiz1tTLwPwCAI6ld7/c64ATo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chengfeng Ye , Steffen Klassert Subject: [PATCH 6.18 254/398] xfrm: serialize state GC with device state flush Date: Wed, 23 Sep 2026 16:05:28 +0200 Message-ID: <20260923140650.000214739@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260923140643.441954610@linuxfoundation.org> References: <20260923140643.441954610@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chengfeng Ye commit 89fefad9f971bc637fb22373078144f2563c4be9 upstream. The deferred-device pass in xfrm_dev_state_flush() finds states under xfrm_state_dev_gc_lock, but drops the lock before calling xfrm_dev_state_free() because the driver callback may sleep. The device GC list does not hold an xfrm_state reference, so the state GC worker can destroy the same state concurrently. The race can proceed as follows: CPU 0 CPU 1 find x on the device GC list drop xfrm_state_dev_gc_lock read x->xso.dev xfrm_state_gc_destroy(x) xfrm_dev_state_free(x) xfrm_state_free(x) continue xfrm_dev_state_free(x) Both paths can invoke the driver callback and drop the device reference. CPU 0 can also access the xfrm_state after CPU 1 has freed it. KASAN reported: BUG: KASAN: slab-use-after-free in xfrm_dev_state_free+0x24c/0x2a0 Read of size 8 at addr ffff88810bbaa960 by task poc/102 Call Trace: xfrm_dev_state_free+0x24c/0x2a0 xfrm_dev_state_flush+0x353/0x400 xfrm_dev_event+0x26d/0x3a0 notifier_call_chain+0xc0/0x280 __dev_notify_flags+0x169/0x250 netif_change_flags+0xe7/0x160 dev_change_flags+0x96/0x220 devinet_ioctl+0x7f4/0x1880 Allocated by task 87: xfrm_state_alloc+0x1e/0x5c0 xfrm_add_sa+0xe7f/0x5820 xfrm_user_rcv_msg+0x4f3/0x940 Freed by task 57: kmem_cache_free+0xcb/0x3d0 xfrm_state_gc_task+0x4a8/0x650 process_one_work+0x63a/0x1070 Serialize xfrm_state destruction against the deferred-device pass with a mutex. Keep xfrm_state_dev_gc_lock limited to list operations and retain the existing callback and device-reference release ordering. Fixes: 07b87f9eea0c ("xfrm: Fix unregister netdevice hang on hardware offload.") Cc: stable@vger.kernel.org Signed-off-by: Chengfeng Ye Signed-off-by: Steffen Klassert Signed-off-by: Greg Kroah-Hartman --- net/xfrm/xfrm_state.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -226,6 +226,7 @@ static struct xfrm_state_afinfo __rcu *x static DEFINE_SPINLOCK(xfrm_state_gc_lock); static DEFINE_SPINLOCK(xfrm_state_dev_gc_lock); +static DEFINE_MUTEX(xfrm_state_gc_mutex); int __xfrm_state_delete(struct xfrm_state *x); @@ -632,8 +633,10 @@ static void xfrm_state_gc_task(struct wo synchronize_rcu(); + mutex_lock(&xfrm_state_gc_mutex); hlist_for_each_entry_safe(x, tmp, &gc_list, gclist) xfrm_state_gc_destroy(x); + mutex_unlock(&xfrm_state_gc_mutex); } static enum hrtimer_restart xfrm_timer_handler(struct hrtimer *me) @@ -1000,6 +1003,7 @@ restart: out: spin_unlock_bh(&net->xfrm.xfrm_state_lock); + mutex_lock(&xfrm_state_gc_mutex); spin_lock_bh(&xfrm_state_dev_gc_lock); restart_gc: hlist_for_each_entry_safe(x, tmp, &xfrm_state_dev_gc_list, dev_gclist) { @@ -1014,6 +1018,7 @@ restart_gc: } spin_unlock_bh(&xfrm_state_dev_gc_lock); + mutex_unlock(&xfrm_state_gc_mutex); xfrm_flush_gc();