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 764C5284693; Fri, 19 Jun 2026 12:46:52 +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=1781873213; cv=none; b=IQ5F1XjxgKAHjxGCTFfmG/fHxfx5ZNdU3L/P3qG488lQ8GExfPNKa6F7wzy6T86Rlcfbr5Y1CjQZ4zybeI+p3ngj7TWlYsQBVpCrAohVrEXADA8zeWaqUseQyhDahFgFz9KW0A083SWn/V+JxjALip71TQpY8dy7f6hKHCFN+bo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781873213; c=relaxed/simple; bh=ZdXAwpBtqN7os8r2hIuw0l9/KJaU/sE3pSEydsgDzGQ=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=HxKz2VB4M9yWRN0AbLOqaJFcjizW0qM4ew1CrcsDWb1x7rdwL0Pdoh+PCHTTkvRXwNwLjQymCrqlSpjwlY3cpNohymIBa47Jbfzu/PfkzU9SSv7SDFoWajxd1IwRYN0KVWZ2iQZ5RgwMi7P4YbCOeKL8El+vU40JCy5qPoDrHWA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dHi7h/uK; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dHi7h/uK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 841F11F000E9; Fri, 19 Jun 2026 12:46:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781873212; bh=OvJ2fMvuTrnYzU+an61M0mr+dkXOs1vZJgrnfKVFoMU=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=dHi7h/uK11Ms4ARbhx4kIA+SgprRrFIAf9dMufNflSpNZeXAO1RYXc6TxilmPvtTM dNWVmvT7ki9G2pkOKfh/qTXSnKhW8EJsjSvppWAm7RvT34luxfzL/7bVzlpBf5Dkuy fERqoBVnvWC0WW30PKXwQHLPrbgmAZdVTW9aUujwt4FH+4kYCg7aOP+wR5sNnbJLxs RBtNq5MybFzhOPdhSnyMazAu2ffi92TogQwhaWukBfn34OcKSevN5jYrEe73QYUlXh zWy0cJR5HBQCqot6b6x+Z3Gei6rgWNVltVz+kzG+efhHXQXzaAGXevOI8wdH3cwZyS gUvfCdLWFbJcQ== From: Thomas Gleixner To: Sebastian Andrzej Siewior Cc: Al Viro , Jann Horn , Peter Zijlstra , Ingo Molnar , Will Deacon , Boqun Feng , Waiman Long , Clark Williams , Steven Rostedt , syzbot , Christian Brauner , Jan Kara , linux-fsdevel , kernel list , syzkaller-bugs , Jeff Layton Subject: Re: rt_spin_unlock order of operations [was: Re: [syzbot] [fs?] KASAN: slab-use-after-free Read in shrink_dcache_tree] In-Reply-To: <20260619083916.UMjUHmaq@linutronix.de> References: <6a32d492.9a9be2da.cfe8.0001.GAE@google.com> <20260618205953.GZ2636677@ZenIV> <20260618210332.GA2636677@ZenIV> <87wlvvcwqt.ffs@fw13> <20260619083916.UMjUHmaq@linutronix.de> Date: Fri, 19 Jun 2026 14:46:49 +0200 Message-ID: <87mrwqd7eu.ffs@fw13> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Fri, Jun 19 2026 at 10:39, Sebastian Andrzej Siewior wrote: > On 2026-06-19 00:24:58 [+0200], Thomas Gleixner wrote: > > would you mind folding the following? I don't see why the rwlocks should > be treated any different. Duh. I wanted to look at it but my brain only works partially in this heat ... > diff --git a/kernel/locking/spinlock_rt.c b/kernel/locking/spinlock_rt.c > index db1e11b45de67..4fb77daafd758 100644 > --- a/kernel/locking/spinlock_rt.c > +++ b/kernel/locking/spinlock_rt.c > @@ -262,17 +262,21 @@ void __sched rt_read_unlock(rwlock_t *rwlock) __releases(RCU) > { > rwlock_release(&rwlock->dep_map, _RET_IP_); > migrate_enable(); > - rcu_read_unlock(); > rwbase_read_unlock(&rwlock->rwbase, TASK_RTLOCK_WAIT); > + > + /* This must be last to prevent, see rt_spin_unlock() */ > + rcu_read_unlock(); > } > EXPORT_SYMBOL(rt_read_unlock); > > void __sched rt_write_unlock(rwlock_t *rwlock) __releases(RCU) > { > rwlock_release(&rwlock->dep_map, _RET_IP_); > - rcu_read_unlock(); > migrate_enable(); > rwbase_write_unlock(&rwlock->rwbase); > + > + /* This must be last to prevent, see rt_spin_unlock() */ > + rcu_read_unlock(); > } > EXPORT_SYMBOL(rt_write_unlock); >