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=1792680572; b=G3gY1r/8NRgD7TGKduyO2Ce+yCo6Mmq11ZLhFehtx+4dBtjWS1soc7Gzad3UNz/MOsj0 ++swa/QtHu/Pe6w5DKw/N3qeN7p+UfTsvPwj52gCDQWYl10AFmSQ5e0LeHzBSKLDFjIcg M/qL7zErFt89DrTTL5ESjka6uY3WJ2DLbVw8J0icNBeY1Kdv/H/f2EBKvK90eq5v7p7ON tBfiYuElD62R6hIGtTKJRozw8csSYUW/Jwjz8pehl5Y7cCQtlgMxprWKRxpKjblA4X5nr Vcs/RNx9JWtJvN0bE+3TUEif5th5jUmdAf9OTpNvYxaYZHpwr8ot2tNF8OBl1BVFkpg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792680572; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=0aGDuZUxKpoClzz6d4lSZ2bW+2WDlBNYNEmjPRhlvjk=; b=CWW4+oxNwdBrYGK91eL4BKzL3uc5wNEvtSHwTdDAbvCcqovFw8wGWYtVfjNv9gIb8Fa0 s3BIlXERuXTe9bP3W0hPfc2LldGkUMcICWyYlSlTVxz6A8Ehczmn+WrcgXBLfRTL6+iZj Ow7hQcH7m1KmYgI0n3+v971HiaocV2Ef+Nhmtn7Q0Ix8XK5W0kSHaAZ6jHLmA+2D2oOu4 meXJM7McibQ6a5vwYEi4WNxE8T1FoMcbvS5QjLt/g7vVI5q3sfhmj7Rh6mx+CrAJkWEQ2 B9T6VyEUtY1I9DAX4BgOty1BmFNkim872iO1fsF2rBtT+OZ7VMT6t2ANL28lvuV/Vrw== 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=AOh4RsER; 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 4F974606A328 for ; Thu, 22 Oct 2026 14:49:32 +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=AOh4RsER Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4594F1F000C3; Thu, 22 Oct 2026 14:49:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792680572; bh=0aGDuZUxKpoClzz6d4lSZ2bW+2WDlBNYNEmjPRhlvjk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=AOh4RsERkUWEo8JNrx/QdWiT6GYL5t0VwrVF9S4rbxnNB5EWlo+0GH22+4ciUT6av HrbkHcFEpadIPA5Px8D/Od4aHE8trpbCADRZ63606HD2lgeGaIB2w2sQFCrg5ET+wW 77tLl78+Be8ehTu67Rv4ippeZtqJcOsCn7wcMvz6mZ5JuZ1LsD9NwJw0n3gHLKA0Y2 SPxVi274VcOzzAy/w771AXCXlz+W/wjdlJuSwzooHAvzeimGfW4EISTH6T2cpAr2iV hzOef8fUK85INTHUq8TFdlRHwPZocePu+XiMaRpfUzE3gsX3AKwcWhiSaYr6pQBN0h XtmVosFc/04Yg== From: Sasha Levin To: stable@vger.kernel.org Cc: Yun Zhou , syzbot+837bcd54843dd6262f2f@syzkaller.appspotmail.com, Christoph Hellwig , Carlos Maiolino , Sasha Levin Subject: [PATCH 6.6.y] xfs: don't hold buffer locks across sync transaction commit in xfs_sync_sb_buf Date: Thu, 22 Oct 2026 10:49:30 -0400 Message-ID: <20261022144858.1630581-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026102121-jacket-unbridle-f8af@gregkh> References: <2026102121-jacket-unbridle-f8af@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 the existing code 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 f4656d17121eb..279e174fba8ac 100644 --- a/fs/xfs/libxfs/xfs_sb.c +++ b/fs/xfs/libxfs/xfs_sb.c @@ -1150,26 +1150,23 @@ 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