From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794047575; b=KLzrbz2eNB/SGo5sLX1rLY9nHZNkm3Av9u4GO65w5fdH4NvdWtusLBEQRv2mY2f7dhMC 5de+qA9knJk5m0EJpUrBnukU4vSCVSjHstEuULvCgHx/ZnvFkVrZ929TX21AObaGvKmP4 QaqF3KvEk/i+3bwkjNtro+duZ4J32NVKmmAZdJyE1hdIUgwuuU+v/EsXn4j3U0A2nD+he M4gxGsHAv4TtW0IlRbpw9wKsypv3M1mlbCh+r0vdjbo2q09DzMN+k+agglEsa/OJw9m4f OOBRk502cYsV4xJb5BgDTGtz8QXZPzKQn+2+JTL/oPbt4508N4ddi+Xnk8/tU32705A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794047575; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=CHi1xo0GGVPu90e87f2bsf4rNNkXhpkGYQCa6ed6v9c=; b=pkfgApFKho1gnrRSkLmOwIUMyyv2GLSoEja2Zk4YKEOwYegmyIF1FJpq5vX+7KYOuuYG vrrXUTZrdj6mQzSAhBqe/6zJBArmhIVPAefnh8P0bxyMGVctG/Ef69nRo5shIzeNs4kvf 9MVIohhSU76ArgeWV4aCyqegsjlOU/V4bgOrRqRWX1XRsfyXq6GXRym55a8XxKLDTde3G 2TLXATM+d97AMrbhFHSffqVVs0To3POUQdxlpY46x73jrNFt0C4wAZSR8fSuK5m0XI1bE SHbym0yZL9RfgSu/wLjVRjGF28gb6DIX2xf1usGVcfSuUKg5BXrWPPNIfOpQLI2T0/Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=gBAeN46N; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5B95C606A32D for ; Sat, 7 Nov 2026 10:32:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=gBAeN46N Received: by smtp.kernel.org (Postfix) with ESMTPSA id 702871F0089F; Sat, 7 Nov 2026 10:32:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794047575; bh=CHi1xo0GGVPu90e87f2bsf4rNNkXhpkGYQCa6ed6v9c=; h=From:To:Cc:Subject:Date; b=gBAeN46NJjtLSXbkOs+9cORYC3NNgCnbeADGBR9FQmP5idati2ZkeFgpmBs9SLYx0 LNLtRe19xJW17wFLbVCt/viHTraF5xvhk9fe9LvBIsbuFAEXKU6FCSj12lGQnIZ0TM thWZ519lwIZhP7cOev9mt4makrDRZpR7z/RBS2nCrBbYTOBqCjbR4G7naOYUlzKhfT tzvK0gAlVlsjY4BH7l1tqCRoeW8HohszQyYm2ZvqM4t2k5QEmtYAzBUQfE9mejPKCS B8Se3yBXgC8ABB0uq8+21QpTZTC126Syp28aE7rWB66eC7Ta2lLzFjJ37GgGGRBcQ6 yL56QYfez8Ugw== From: Sasha Levin To: senozhatsky@chromium.org, sarthakkukreti@google.com, jack@suse.cz, libaokun@linux.alibaba.com, yi.zhang@huawei.com, tytso@mit.edu Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] ext4: fix ABBA deadlock in ext4_rmdir()" failed to apply to 6.6-stable tree Date: Sat, 7 Nov 2026 05:32:53 -0500 Message-ID: <20261107053253-failed-6.6-19e16597f9ba@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 19e16597f9baf1b5719a3a6c710486446f6808fd # git commit -s git send-email --to '' --in-reply-to '20261107053253-failed-6.6-19e16597f9ba@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 19e16597f9baf1b5719a3a6c710486446f6808fd Mon Sep 17 00:00:00 2001 From: Sergey Senozhatsky Date: Thu, 27 Aug 2026 21:50:20 +0900 Subject: [PATCH] ext4: fix ABBA deadlock in ext4_rmdir() We observe the following ABBA deadlock (casefolding enabled): INFO: task jbd2/dm-13-8:447 blocked for more than 720 seconds. task:jbd2/dm-13-8 state:D stack:0 pid:447 tgid:447 ppid:2 Call Trace: __schedule+0xc2c/0xe60 schedule+0x40/0xe0 jbd2_journal_wait_updates+0x8f/0xf0 jbd2_journal_commit_transaction+0x321/0x1850 kjournald2+0xa9/0x230 kthread+0x226/0x2a0 ret_from_fork+0x101/0x1e0 ret_from_fork_asm+0x1a/0x30 INFO: task Thread-10:4161 blocked for more than 720 seconds. task:Thread-10 state:D stack:0 pid:4161 tgid:3848 ppid:540 Call Trace: __schedule+0xc2c/0xe60 schedule+0x40/0xe0 wait_transaction_locked+0x8c/0xd0 start_this_handle+0x252/0x870 jbd2__journal_start+0x120/0x280 __ext4_journal_start_sb+0x11a/0x250 ext4_evict_inode+0x208/0x760 iput+0x222/0x5c0 dput+0x293/0x690 ____fput+0x145/0x2b0 task_work_run+0x7a/0xb0 exit_to_user_mode_loop+0xc0/0xd0 do_syscall_64+0x14b/0xf10 entry_SYSCALL_64_after_hwframe+0x76/0x7e NMI backtrace for cpu 0 CPU: 0 UID: 1010216 PID: 4160 Comm: Thread-7 RIP: 0010:d_walk+0x0/0x290 [..] Call Trace: shrink_dcache_parent+0xb2/0x100 d_invalidate+0x50/0x110 ext4_rmdir+0x3a2/0x3d0 vfs_rmdir+0x9d/0x1d0 do_rmdir+0xf0/0x330 __x64_sys_unlinkat+0x34/0x50 do_syscall_64+0x61/0xf10 The problem is that ext4_rmdir() calls d_invalidate() before stopping the jbd2 transaction handle. Because d_invalidate() traverses child dentries it can encounter dying or in-use dentries. If a concurrent thread executing __dentry_kill() on a child dentry invokes ext4_evict_inode(), it requests a new transaction handle via ext4_journal_start(), which waits for all running handles to close. However, the thread executing ext4_rmdir() still holds its active transaction handle while looping in shrink_dcache_parent() waiting for the dying child dentry to complete eviction. Stop transaction handle in ext4_rmdir() before calling d_invalidate(). Cc: stable@kernel.org Fixes: b886ee3e778e ("ext4: Support case-insensitive file name lookups") Co-developed-by: Sarthak Kukreti Signed-off-by: Sarthak Kukreti Signed-off-by: Sergey Senozhatsky Reviewed-by: Jan Kara Reviewed-by: Baokun Li Reviewed-by: Zhang Yi Link: https://patch.msgid.link/20260827125158.4030598-1-senozhatsky@chromium.org Signed-off-by: Theodore Ts'o --- fs/ext4/namei.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index a6386c1d237f1..231a274b814ec 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3209,19 +3209,20 @@ static int ext4_rmdir(struct inode *dir, struct dentry *dentry) ext4_fc_track_unlink(handle, dentry); retval = ext4_mark_inode_dirty(handle, dir); +end_rmdir: + brelse(bh); + if (handle) + ext4_journal_stop(handle); + /* VFS negative dentries are incompatible with Encoding and * Case-insensitiveness. Eventually we'll want avoid * invalidating the dentries here, alongside with returning the * negative dentries at ext4_lookup(), when it is better * supported by the VFS for the CI case. */ - if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir)) + if (!retval && IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir)) d_invalidate(dentry); -end_rmdir: - brelse(bh); - if (handle) - ext4_journal_stop(handle); return retval; } -- 2.53.0