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=1792706612; b=nwpK4obQlLLqpgbRQ2xPzU8opaGxe5vhLbT6+oUrntvTN8KiZUThfzo45GknfmD7OxrF CIzDZFyMBbdfPRBMjiOfvS9UgmGmrBKNAV+sBN3VkHF09/QPNhXTtep/Uk4GFRT08ars8 GjaUj0TlTpOJaxJnbwr0JX+dJhs4jGm+VnwCRnV+fSsMSHMMe4VXrTPiKoC1+ZksLsC+b qAWYZlmf7tBru4qV7EpHzZO64AzkffHXob9McsFhttKWun2Io4Wc7d0Xs9GkPjI1EWEon G0I4PIOv0vX/TG9HgAh5FxiTcfuuB5nyLvT7EhJvhoBiHX691+FzsuG92ENi+6+wrPQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792706612; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=nB3f7kL12FAQgMsIR+ldz47T23GddoXXrgM293AAQ0Y=; b=sxMUF3eLzX+GFvbhVxho6T8t6r+S/y7ty5s31wL73eE1nvOo3gJ8rgLXxQ7FmfkdWKiK KRTo0dV1+2oI3NZt5NLtRujKDkx4QB4jDixCZkgckNAJlp4yQZ60YSzsdR81euX86ygt0 ExhQbu5NKyC2QnSNK9w1LNeG+AJPssBS2XU4v9eIXkihM8eLFDjsrlLgLEcVnk7D87N7Q wtRHmXK2jri3EHrfVsvug762JQQleAqZl6osw02CpUqp9TyWGUIwZJ9GMl4YeII283CMT mKVLCSld3mg6lZhdh2TUc/ziuNgxNqENzDrek5G5noRu5XkjDBaK3RNNKGXkG0YetxA== 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=D3FrBTPT; 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 71874606A319 for ; Thu, 22 Oct 2026 22:03:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=D3FrBTPT Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8ED791F01825; Thu, 22 Oct 2026 22:03:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792706612; bh=nB3f7kL12FAQgMsIR+ldz47T23GddoXXrgM293AAQ0Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=D3FrBTPTuLultpYI5csuod8Ahkc1nK5ZBYmQWFdb8KC3gqEQ6d3VxV8EYmDHuHsRg 5NV/uyExqHX333S0EZaD+mBerzSUrmfE1dy4VTzEy2vR38hLqz1400YVK524+tpX4e sPkUFinQjqacfJqbrCmUa/Gwua7wd/6e/ABpY6dzlx+R3EYQHA2pyU0hpXtDBYHHrZ fzNX+QBZPLwlM6r+JLNjGQKiayzccgueoOC96K13//qSx5JBnPNAA11t2shVfxJ4w+ ueSQ/DGRJvz7YnLKC/ySNRDGa5+KC5etc2VNSUatpDXP8p3arsoCjo/6oZiHgDck9n WUTsbCWiCvlPQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Yun Zhou , syzbot+837bcd54843dd6262f2f@syzkaller.appspotmail.com, Christoph Hellwig , Carlos Maiolino , Sasha Levin Subject: [PATCH 5.10.y] xfs: don't hold buffer locks across sync transaction commit in xfs_sync_sb_buf Date: Thu, 22 Oct 2026 18:03:29 -0400 Message-ID: <20261022220226.1913649-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026102122-mural-modulator-6339@gregkh> References: <2026102122-mural-modulator-6339@gregkh> 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-Transfer-Encoding: 8bit From: Yun Zhou [ Upstream commit 41a28c865d1d5843f8cb9e0af17a8f4d9e2961ff ] xfs_sync_sb_buf() holds sb/rtsb buffer locks across a synchronous xfs_trans_commit(), which flushes the CIL push workqueue internally. If shutdown occurs during the CIL push, xfs_buf_item_unpin() needs to lock these buffers to fail them, causing a deadlock: setlabel: holds buf lock -> flush_workqueue(xfs-cil) CIL push worker: xfs_buf_item_unpin -> xfs_buf_lock(same buf) Remove the xfs_trans_bhold() calls so that commit releases the buffer locks normally. After the sync commit, re-acquire the buffers via mp->m_sb_bp / mp->m_rtsb_bp for the on-disk writeback. Fixes: f7664b31975b ("xfs: implement online get/set fs label") Reported-by: syzbot+837bcd54843dd6262f2f@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=837bcd54843dd6262f2f Cc: stable@vger.kernel.org Signed-off-by: Yun Zhou Reviewed-by: Christoph Hellwig Signed-off-by: Carlos Maiolino [ sashal: Omitted realtime superblock changes because xfs_sync_sb_buf() lacks realtime superblock support. ] Signed-off-by: Sasha Levin --- fs/xfs/libxfs/xfs_sb.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c index 40b31fa6687b7..2cc8da99a42e4 100644 --- a/fs/xfs/libxfs/xfs_sb.c +++ b/fs/xfs/libxfs/xfs_sb.c @@ -1151,26 +1151,23 @@ xfs_sync_sb_buf( struct xfs_mount *mp) { struct xfs_trans *tp; - struct xfs_buf *bp; int error; error = xfs_trans_alloc(mp, &M_RES(mp)->tr_sb, 0, 0, 0, &tp); if (error) return error; - bp = xfs_trans_getsb(tp); xfs_log_sb(tp); - xfs_trans_bhold(tp, bp); xfs_trans_set_sync(tp); error = xfs_trans_commit(tp); if (error) - goto out; - /* - * write out the sb buffer to get the changes to disk - */ - error = xfs_bwrite(bp); -out: - xfs_buf_relse(bp); + return error; + + /* Re-acquire and write the sb to disk. */ + xfs_buf_lock(mp->m_sb_bp); + error = xfs_bwrite(mp->m_sb_bp); + xfs_buf_unlock(mp->m_sb_bp); + return error; } -- 2.53.0