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=1794049224; b=h6yX4uMN42AJma/MK+K1DQYck2GK8RMwt6mJrEJ+RxnLxy9Qe8QWWJ+mWQCp5QODajPG xFRhUzGVBG3qBoytBKRPF+rKyblSGg1RFujL10ab2UMeWnNdL/r5UiDmLLMPejs2n0dFO RJaSCEXv4cI1NhIhGAM49+iP/HhCjJdXcswdIpzfwqXQ4WOt0uPknHpyKXWCynHkG581K bnehxZFCynvnbqHs3XNPDJMQDRWZHRkH+9TIFCGvtBLlHvD9oGPuOj/2Rxk6WcMI1pHWs mOyEDDgyzGqQwA3g9ILWB3iM9CJsM3Cb91GL+ghSyafT43YuDv66Zf4vrMn0BT1oC8g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794049224; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=1dux/bRdNMtL4rxhL3LJmECUgaG3vS4GHLThxcseBmA=; b=v2P69aGq4+iKL9Qgq7mJOmr2TP1fbUeij8rfhkTg7jzkBHJn3Rg7tgJ3yUvuHgXqss/0 37uLOQh/pJ9zMEh1JA1oDKRH1Xe3awHt+HtdZKxf7Iw9VvyGIbmME7m5NmibnuYT5ocPY EOTnbdTeMxqz5z8aAxog05+GjwuBiYjRS3kjJ3DJgDHSJSkEwsHUejKY+Wrrsd30HbA/d VcqQnuOGE4xYZgr243Hs0v/y+LRdzMKJyxw4ty8YaYdvIiBjBv6iArJhv8iSUtGidoDzx 3Svk7QssR460K/cZVN9BfBTjur+fKy5p7e4IxB1HU/pX9nHjvdVQvLwo6TsbphJFqPQ== 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=lugGWp4s; 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 816BC606A32D for ; Sat, 7 Nov 2026 11:00:24 +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=lugGWp4s Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBB8A1F0089F; Sat, 7 Nov 2026 11:00:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794049224; bh=1dux/bRdNMtL4rxhL3LJmECUgaG3vS4GHLThxcseBmA=; h=From:To:Cc:Subject:Date; b=lugGWp4sBbRF19i7AYPbzh+njV/RpRicmNG7mupfKsRLe5uvqEI5Kjb3mw/u0iklg XQmEK/SRmLu7SCFxLI8J4lV8aXt/bWDmTr1xiXG8EVHj6Fqi1g9AN2wK7wUUVHmSfp DJoSBN4JUHzTImN85D9goktn1juQiAxA4kLnhndM5siH6cTFUzLS0LQwjJJbkhUw6M lFYtErqdKECido5Beh+znp092yHJkBXOX9Hi8mV5wsVsWad8fg0v6Ek0feplHOR5mR ssDXEHE/3Av6p8bXhezJkIbiFfpjzdXQl+JHA13EE6VcwT8rANC3tyYlFeda7L9kVS I8GXY6dJj6zRQ== From: Sasha Levin To: leitao@debian.org, paulmck@kernel.org, brauner@kernel.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] dcache: report a Tasks-RCU quiescent state in dentry_kill()" failed to apply to 5.15-stable tree Date: Sat, 7 Nov 2026 06:00:22 -0500 Message-ID: <20261107060022-failed-5.15-a647a53bc89a@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 5.15-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-5.15.y git checkout FETCH_HEAD git cherry-pick -x a647a53bc89a046bee4a12a0a5627f2dfaaef807 # git commit -s git send-email --to '' --in-reply-to '20261107060022-failed-5.15-a647a53bc89a@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From a647a53bc89a046bee4a12a0a5627f2dfaaef807 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Fri, 18 Sep 2026 04:01:57 -0700 Subject: [PATCH] dcache: report a Tasks-RCU quiescent state in dentry_kill() I am constantly seeing the following warning on Meta's fleet: INFO: rcu_tasks detected stalls on tasks: native_queued_spin_lock_slowpath locked_inode_to_wb_and_lock_list inode_io_list_del evict __dentry_kill shrink_dentry_list shrink_dcache_tree d_invalidate btrfs_delete_subvolume btrfs_ioctl_snap_destroy btrfs_ioctl do_syscall_64 dentry_kill() is the common funnel for dentry teardown: dput(), shrink_dentry_list() and shrink_dcache_tree() all reach it, once per dentry, and its cond_resched() is the only reschedule point on that path. cond_resched() is not an RCU-tasks quiescent state. Use cond_resched_tasks_rcu_qs() so the teardown reports an RCU-tasks quiescent state as it proceeds. Fixes: 9c5f1d30199d ("dcache: move cond_resched() into the end of __dentry_kill()") Cc: stable@vger.kernel.org Signed-off-by: Breno Leitao Link: https://patch.msgid.link/20260918-dcache-task-rcu-qa-v1-1-963ec83e6d0b@debian.org Reviewed-by: Paul E. McKenney Signed-off-by: Christian Brauner (Amutable) --- fs/dcache.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/dcache.c b/fs/dcache.c index 8f17db2724b38..e974d42b03e72 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -843,7 +843,7 @@ static struct dentry *dentry_kill(struct dentry *dentry) if (dentry->d_op && dentry->d_op->d_release) dentry->d_op->d_release(dentry); - cond_resched(); + cond_resched_tasks_rcu_qs(); /* now that it's negative, ->d_parent is stable */ if (!IS_ROOT(dentry)) { parent = dentry->d_parent; -- 2.53.0