From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pdx-out-006.esa.us-west-2.outbound.mail-perimeter.amazon.com (pdx-out-006.esa.us-west-2.outbound.mail-perimeter.amazon.com [52.26.1.71]) (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 A5FAD31A07F; Tue, 10 Mar 2026 18:38:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.26.1.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773167936; cv=none; b=gCkPcmfAKl1CkqqHpFy0rD7kfpJ29ht8w5C9+hshJI6FnbALLbTpgPcatY+bOYM26A6Z0h8UKPvisVbocDwO0vxvqn+Udc4n3LHcnBtyzHaWNBVR9JL1MKd4XlVQoq6qd/7n4IqLp1ERtfE9j6E2WuoRnos+rfSgvtV6g2tpjjw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773167936; c=relaxed/simple; bh=rIVnGInd1Kc7Lfu07d1MuB7hupkdwmJcYNnvcOPk9Kk=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=gR3j0jMk1nVPCxzLEjQO4yKfNCN052ezXOXtG7EIIg/TgUOLPyW+hXDDKiwe2Y1W6py3s6jJ+G84se2HwXsldBg3N0dAMNpMwcYvwtzj8ZA4KOXs97ukn6OMcgT3ZKyboTdfZ2p8i2+0kdcJgjDpplis/31mgREizUO7lUDCsaQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.com; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b=e8sroEZ0; arc=none smtp.client-ip=52.26.1.71 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b="e8sroEZ0" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1773167935; x=1804703935; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=5xv1p9eU47NVp3o9CONDiQJ1V9HKJVb9C2TnW6MdRvY=; b=e8sroEZ0Yb6QlVv2DcaYqL6adc/OZnm8YNtvCtEaJ3qk3PIBQXBflR5F buUStUSJcLvyv8L50tu5lCZUe7bGxZmB63qz12lE+mqmTPQ2ED7BMDINq ilhKMyvckIferjQCDVaq5oFCWe6w9a62EC82Dx59Ip8ef0EX64YVZ+UI4 QTW969suaAPotpB0O6tL/ptAvvyBws1zFDRyFih+k45fwen86anOKow35 TQzOZ3VXlO9AJ+hHu/BJQonW67ws8J4LH31pU4UihVw0VinKVb1wEFoA5 GWiwuSzBAO01uDDqTOHbou/3qPKB1gf2ofwCezGodQPoMK37VV3NbvTA9 Q==; X-CSE-ConnectionGUID: Zssv5p6xQ5qJrtvDYpksNw== X-CSE-MsgGUID: 964qTTVhSkul/FQ5HOYJYA== X-IronPort-AV: E=Sophos;i="6.23,112,1770595200"; d="scan'208";a="14738412" Received: from ip-10-5-0-115.us-west-2.compute.internal (HELO smtpout.naws.us-west-2.prod.farcaster.email.amazon.dev) ([10.5.0.115]) by internal-pdx-out-006.esa.us-west-2.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Mar 2026 18:38:54 +0000 Received: from EX19MTAUWA001.ant.amazon.com [205.251.233.236:23881] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.4.108:2525] with esmtp (Farcaster) id d3e8d478-92a2-4f29-b065-91f9d57ca7df; Tue, 10 Mar 2026 18:38:54 +0000 (UTC) X-Farcaster-Flow-ID: d3e8d478-92a2-4f29-b065-91f9d57ca7df Received: from EX19D001UWA001.ant.amazon.com (10.13.138.214) by EX19MTAUWA001.ant.amazon.com (10.250.64.217) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.37; Tue, 10 Mar 2026 18:38:54 +0000 Received: from c889f3b07a0a.amazon.com (10.106.82.15) by EX19D001UWA001.ant.amazon.com (10.13.138.214) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.37; Tue, 10 Mar 2026 18:38:52 +0000 From: Yuto Ohnuki To: Carlos Maiolino , Dave Chinner CC: "Darrick J . Wong" , Brian Foster , , , Yuto Ohnuki , , Subject: [PATCH v4 2/4] xfs: avoid dereferencing log items after push callbacks Date: Tue, 10 Mar 2026 18:38:38 +0000 Message-ID: <20260310183835.89827-8-ytohnuki@amazon.com> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20260310183835.89827-6-ytohnuki@amazon.com> References: <20260310183835.89827-6-ytohnuki@amazon.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: EX19D036UWC002.ant.amazon.com (10.13.139.242) To EX19D001UWA001.ant.amazon.com (10.13.138.214) Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit After xfsaild_push_item() calls iop_push(), the log item may have been freed if the AIL lock was dropped during the push. Background inode reclaim or the dquot shrinker can free the log item while the AIL lock is not held, and the tracepoints in the switch statement dereference the log item after iop_push() returns. Fix this by capturing the log item type, flags, and LSN before calling xfsaild_push_item(), and introducing a new xfs_ail_push_class trace event class that takes these pre-captured values and the ailp pointer instead of the log item pointer. Reported-by: syzbot+652af2b3c5569c4ab63c@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=652af2b3c5569c4ab63c Fixes: 90c60e164012 ("xfs: xfs_iflush() is no longer necessary") Cc: # v5.9 Signed-off-by: Yuto Ohnuki --- fs/xfs/xfs_trace.h | 36 ++++++++++++++++++++++++++++++++---- fs/xfs/xfs_trans_ail.c | 26 +++++++++++++++++++------- 2 files changed, 51 insertions(+), 11 deletions(-) diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index 813e5a9f57eb..0e994b3f768f 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -56,6 +56,7 @@ #include struct xfs_agf; +struct xfs_ail; struct xfs_alloc_arg; struct xfs_attr_list_context; struct xfs_buf_log_item; @@ -1650,16 +1651,43 @@ TRACE_EVENT(xfs_log_force, DEFINE_EVENT(xfs_log_item_class, name, \ TP_PROTO(struct xfs_log_item *lip), \ TP_ARGS(lip)) -DEFINE_LOG_ITEM_EVENT(xfs_ail_push); -DEFINE_LOG_ITEM_EVENT(xfs_ail_pinned); -DEFINE_LOG_ITEM_EVENT(xfs_ail_locked); -DEFINE_LOG_ITEM_EVENT(xfs_ail_flushing); DEFINE_LOG_ITEM_EVENT(xfs_cil_whiteout_mark); DEFINE_LOG_ITEM_EVENT(xfs_cil_whiteout_skip); DEFINE_LOG_ITEM_EVENT(xfs_cil_whiteout_unpin); DEFINE_LOG_ITEM_EVENT(xlog_ail_insert_abort); DEFINE_LOG_ITEM_EVENT(xfs_trans_free_abort); +DECLARE_EVENT_CLASS(xfs_ail_push_class, + TP_PROTO(struct xfs_ail *ailp, uint type, unsigned long flags, xfs_lsn_t lsn), + TP_ARGS(ailp, type, flags, lsn), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(uint, type) + __field(unsigned long, flags) + __field(xfs_lsn_t, lsn) + ), + TP_fast_assign( + __entry->dev = ailp->ail_log->l_mp->m_super->s_dev; + __entry->type = type; + __entry->flags = flags; + __entry->lsn = lsn; + ), + TP_printk("dev %d:%d lsn %d/%d type %s flags %s", + MAJOR(__entry->dev), MINOR(__entry->dev), + CYCLE_LSN(__entry->lsn), BLOCK_LSN(__entry->lsn), + __print_symbolic(__entry->type, XFS_LI_TYPE_DESC), + __print_flags(__entry->flags, "|", XFS_LI_FLAGS)) +) + +#define DEFINE_AIL_PUSH_EVENT(name) \ +DEFINE_EVENT(xfs_ail_push_class, name, \ + TP_PROTO(struct xfs_ail *ailp, uint type, unsigned long flags, xfs_lsn_t lsn), \ + TP_ARGS(ailp, type, flags, lsn)) +DEFINE_AIL_PUSH_EVENT(xfs_ail_push); +DEFINE_AIL_PUSH_EVENT(xfs_ail_pinned); +DEFINE_AIL_PUSH_EVENT(xfs_ail_locked); +DEFINE_AIL_PUSH_EVENT(xfs_ail_flushing); + DECLARE_EVENT_CLASS(xfs_ail_class, TP_PROTO(struct xfs_log_item *lip, xfs_lsn_t old_lsn, xfs_lsn_t new_lsn), TP_ARGS(lip, old_lsn, new_lsn), diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c index 923729af4206..63266d31b514 100644 --- a/fs/xfs/xfs_trans_ail.c +++ b/fs/xfs/xfs_trans_ail.c @@ -365,6 +365,12 @@ xfsaild_resubmit_item( return XFS_ITEM_SUCCESS; } +/* + * Push a single log item from the AIL. + * + * @lip may have been released and freed by the time this function returns, + * so callers must not dereference the log item afterwards. + */ static inline uint xfsaild_push_item( struct xfs_ail *ailp, @@ -505,7 +511,10 @@ xfsaild_push( lsn = lip->li_lsn; while ((XFS_LSN_CMP(lip->li_lsn, ailp->ail_target) <= 0)) { - int lock_result; + int lock_result; + uint type = lip->li_type; + unsigned long flags = lip->li_flags; + xfs_lsn_t item_lsn = lip->li_lsn; if (test_bit(XFS_LI_FLUSHING, &lip->li_flags)) goto next_item; @@ -514,14 +523,17 @@ xfsaild_push( * Note that iop_push may unlock and reacquire the AIL lock. We * rely on the AIL cursor implementation to be able to deal with * the dropped lock. + * + * The log item may have been freed by the push, so it must not + * be accessed or dereferenced below this line. */ lock_result = xfsaild_push_item(ailp, lip); switch (lock_result) { case XFS_ITEM_SUCCESS: XFS_STATS_INC(mp, xs_push_ail_success); - trace_xfs_ail_push(lip); + trace_xfs_ail_push(ailp, type, flags, item_lsn); - ailp->ail_last_pushed_lsn = lsn; + ailp->ail_last_pushed_lsn = item_lsn; break; case XFS_ITEM_FLUSHING: @@ -537,22 +549,22 @@ xfsaild_push( * AIL is being flushed. */ XFS_STATS_INC(mp, xs_push_ail_flushing); - trace_xfs_ail_flushing(lip); + trace_xfs_ail_flushing(ailp, type, flags, item_lsn); flushing++; - ailp->ail_last_pushed_lsn = lsn; + ailp->ail_last_pushed_lsn = item_lsn; break; case XFS_ITEM_PINNED: XFS_STATS_INC(mp, xs_push_ail_pinned); - trace_xfs_ail_pinned(lip); + trace_xfs_ail_pinned(ailp, type, flags, item_lsn); stuck++; ailp->ail_log_flush++; break; case XFS_ITEM_LOCKED: XFS_STATS_INC(mp, xs_push_ail_locked); - trace_xfs_ail_locked(lip); + trace_xfs_ail_locked(ailp, type, flags, item_lsn); stuck++; break; -- 2.50.1 Amazon Web Services EMEA SARL, 38 avenue John F. Kennedy, L-1855 Luxembourg, R.C.S. Luxembourg B186284 Amazon Web Services EMEA SARL, Irish Branch, One Burlington Plaza, Burlington Road, Dublin 4, Ireland, branch registration number 908705