From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 19CFC273803; Fri, 31 Oct 2025 04:20:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761884411; cv=none; b=h/j1ovDnkHqSUD7MyjSFd9i0rzMmx03/jltChqTjC54y3qGP+SxhodnDUqc51u2yIhWL1TBoLbTfQzxaA/fcovfM8iBd++L8Q5eFcLXzXNN9k3iCgO2YXoD7duzHftziLuuvD6FT+3rfAfnYkcfFW56uHz48dXdAfmMNNli5plA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761884411; c=relaxed/simple; bh=RpWLEx/hY1HUCYETjsc6DQVxiV1NBa7nSxNwgCcxgNk=; h=Date:To:From:Subject:Message-Id; b=u+pC/QmQGeMgoYCS8GRKuIxmSaHeELA2c8FDPFwDEJzdQoapujrRrMDuJ/mJHHjOwizHDLRd1qNe4lVpt8IzOd5zvzJRiaO0TLbrA2EW97SUaqiW3lLPJlWycxwEl9K4evqfUmzn0b/h5ED0aavvIEhk9Ya9sFaGcm1Vu/7JFEg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=HWBxe1fx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="HWBxe1fx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 764EEC4CEE7; Fri, 31 Oct 2025 04:20:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1761884410; bh=RpWLEx/hY1HUCYETjsc6DQVxiV1NBa7nSxNwgCcxgNk=; h=Date:To:From:Subject:From; b=HWBxe1fxUGw92nexDm4N0E3wEmEx0geilB3w2iSvJBxKfVgV3SxiuDl6eD/UkVIQ+ lDy7ZgFZRHk3NPqcwxRvG6H9mSDMBY17Gss7ZWTkBgC1opWlOI4L8kF6EsFTRpB+o1 +mfKJ74WzEhqWoo0noyz9NwTvPMFOvqiL/tDXZoI= Date: Thu, 30 Oct 2025 21:20:09 -0700 To: mm-commits@vger.kernel.org,stable@vger.kernel.org,konishi.ryusuke@gmail.com,eadavis@qq.com,akpm@linux-foundation.org From: Andrew Morton Subject: + nilfs2-avoid-having-an-active-sc_timer-before-freeing-sci.patch added to mm-hotfixes-unstable branch Message-Id: <20251031042010.764EEC4CEE7@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: nilfs2: avoid having an active sc_timer before freeing sci has been added to the -mm mm-hotfixes-unstable branch. Its filename is nilfs2-avoid-having-an-active-sc_timer-before-freeing-sci.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/nilfs2-avoid-having-an-active-sc_timer-before-freeing-sci.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Edward Adam Davis Subject: nilfs2: avoid having an active sc_timer before freeing sci Date: Thu, 30 Oct 2025 07:51:52 +0900 Because kthread_stop did not stop sc_task properly and returned -EINTR, the sc_timer was not properly closed, ultimately causing the problem [1] reported by syzbot when freeing sci due to the sc_timer not being closed. Because the thread sc_task main function nilfs_segctor_thread() returns 0 when it succeeds, when the return value of kthread_stop() is not 0 in nilfs_segctor_destroy(), we believe that it has not properly closed sc_timer. We use timer_shutdown_sync() to sync wait for sc_timer to shutdown, and set the value of sc_task to NULL under the protection of lock sc_state_lock, so as to avoid the issue caused by sc_timer not being properly shutdowned. [1] ODEBUG: free active (active state 0) object: 00000000dacb411a object type: timer_list hint: nilfs_construction_timeout Call trace: nilfs_segctor_destroy fs/nilfs2/segment.c:2811 [inline] nilfs_detach_log_writer+0x668/0x8cc fs/nilfs2/segment.c:2877 nilfs_put_super+0x4c/0x12c fs/nilfs2/super.c:509 Link: https://lkml.kernel.org/r/20251029225226.16044-1-konishi.ryusuke@gmail.com Fixes: 3f66cc261ccb ("nilfs2: use kthread_create and kthread_stop for the log writer thread") Signed-off-by: Ryusuke Konishi Reported-by: syzbot+24d8b70f039151f65590@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=24d8b70f039151f65590 Tested-by: syzbot+24d8b70f039151f65590@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis Cc: [6.12+] Signed-off-by: Andrew Morton --- fs/nilfs2/segment.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/fs/nilfs2/segment.c~nilfs2-avoid-having-an-active-sc_timer-before-freeing-sci +++ a/fs/nilfs2/segment.c @@ -2768,7 +2768,12 @@ static void nilfs_segctor_destroy(struct if (sci->sc_task) { wake_up(&sci->sc_wait_daemon); - kthread_stop(sci->sc_task); + if (kthread_stop(sci->sc_task)) { + spin_lock(&sci->sc_state_lock); + sci->sc_task = NULL; + timer_shutdown_sync(&sci->sc_timer); + spin_unlock(&sci->sc_state_lock); + } } spin_lock(&sci->sc_state_lock); _ Patches currently in -mm which might be from eadavis@qq.com are nilfs2-avoid-having-an-active-sc_timer-before-freeing-sci.patch