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Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1x7WM2-006fie-1o; Fri, 18 Sep 2026 11:02:06 +0000 From: Breno Leitao Date: Fri, 18 Sep 2026 04:01:57 -0700 Subject: [PATCH] dcache: report a Tasks-RCU quiescent state in dentry_kill() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260918-dcache-task-rcu-qa-v1-1-963ec83e6d0b@debian.org> X-B4-Tracking: v=1; b=H4sIACQarWoC/yXMTQqDQAxA4atI1gac0Yr2KuJiJsaaFvyZqAji3 Z22y2/x3gnKQVjhmZwQeBeVaYwwaQI0uPHFKF002MyWWW0q7MjRwLg6/WCgDReHvvDkTd6bhy0 ghnPgXo7ftGn/1s2/mdbvCa7rBgSNhFB2AAAA X-Change-ID: 20260918-dcache-task-rcu-qa-b4bcb13f1524 To: Alexander Viro , Christian Brauner , Jan Kara Cc: linux-fsdevel@vger.kernel.org, paulmck@kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, stable@vger.kernel.org, Breno Leitao X-Mailer: b4 0.15-dev-47773 X-Developer-Signature: v=1; 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a=openpgp; fpr=AC8539A6E8F46702CA4A439B35A3939FFC78776D X-Debian-User: leitao 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 Reviewed-by: Paul E. McKenney --- fs/dcache.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/dcache.c b/fs/dcache.c index 1b1a81f10da67..b89c8480b655b 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -830,7 +830,7 @@ static struct dentry *dentry_kill(struct dentry *dentry) if (dentry->d_op && dentry->d_op->d_release) dentry->d_op->d_release(dentry); =20 - cond_resched(); + cond_resched_tasks_rcu_qs(); /* now that it's negative, ->d_parent is stable */ if (!IS_ROOT(dentry)) { parent =3D dentry->d_parent; --- base-commit: 5dd1818b15d98d4a20806cd00b1b40320b06004f change-id: 20260918-dcache-task-rcu-qa-b4bcb13f1524 Best regards, -- =20 Breno Leitao