From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751301AbdHaDvl (ORCPT ); Wed, 30 Aug 2017 23:51:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51168 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750814AbdHaDvj (ORCPT ); Wed, 30 Aug 2017 23:51:39 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 4DAB8883CA Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=xzhou@redhat.com Date: Thu, 31 Aug 2017 11:51:37 +0800 From: Xiong Zhou To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: fanotify_mark FAN_MARK_FLUSH | _MOUNT stress blocks write to directory Message-ID: <20170831035137.hg6arnj2lq5lcmri@XZHOUW.usersys.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: NeoMutt/20170714-19-95cc18 (1.8.3) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Thu, 31 Aug 2017 03:51:39 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org hi, This happens on 4.13.0-rc7+ to commit 42ff72c After firing up the stress, touch a file in monitoring directory could hang like forever. Pretty easy to hit. Thanks, Xiong [ 492.060879] INFO: task touch:2259 blocked for more than 120 seconds. [ 492.093497] Not tainted 4.13.0-rc7-master-42ff72c+ #9 [ 492.121049] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 492.156289] touch D 0 2259 2233 0x00000080 [ 492.180880] Call Trace: [ 492.191813] __schedule+0x28d/0x890 [ 492.207440] schedule+0x36/0x80 [ 492.221529] fanotify_handle_event+0x2a1/0x2f0 [ 492.241542] ? remove_wait_queue+0x60/0x60 [ 492.260150] fsnotify+0x2d3/0x4f0 [ 492.275055] ? security_inode_init_security+0xd2/0x190 [ 492.298097] security_file_open+0x89/0x90 [ 492.316038] do_dentry_open+0x139/0x330 [ 492.333216] vfs_open+0x4f/0x70 [ 492.347225] ? may_open+0x5a/0x100 [ 492.362481] path_openat+0x548/0x13b0 [ 492.378958] do_filp_open+0x91/0x100 [ 492.394969] ? __alloc_fd+0x46/0x170 [ 492.410930] do_sys_open+0x124/0x210 [ 492.426927] SyS_open+0x1e/0x20 [ 492.440963] do_syscall_64+0x67/0x150 [ 492.457367] entry_SYSCALL64_slow_path+0x25/0x25 [ 492.478251] RIP: 0033:0x7fe877f8e5a0 [ 492.495755] RSP: 002b:00007ffe57120318 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 [ 492.529911] RAX: ffffffffffffffda RBX: 00007ffe57120578 RCX: 00007fe877f8e5a0 [ 492.561508] RDX: 00000000000001b6 RSI: 0000000000000941 RDI: 00007ffe5712268c [ 492.595577] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 492.631144] R10: 00007ffe57120030 R11: 0000000000000246 R12: 00007ffe5712268c [ 492.664970] R13: 00007fe8782612a0 R14: 0000000000000001 R15: 0000000000000000 -------------------------------- $ cat test.sh #!/bin/bash -x fallocate -l 2G test.img mkfs.xfs -fq test.img mkdir -p testdir mount -o loop test.img testdir || exit SCRATCH_MNT=$(readlink -f testdir) function clean () { while ps -eo comm | grep -q -e fanotify ; do killall fanotify_flush_stress done umount -d $SCRATCH_MNT rm -rf test.img scrc $SCRATCH_MNT fanotify_flush_stress } trap "clean; exit;" 2 cc fanotify_flush_stress.c -o fanotify_flush_stress ./fanotify_flush_stress $SCRATCH_MNT & ./fanotify_flush_stress $SCRATCH_MNT & ./fanotify_flush_stress $SCRATCH_MNT & ps jf | grep fanotify touch $SCRATCH_MNT/1 # hang clean -------------------------------- $ cat fanotify_flush_stress.c #define _GNU_SOURCE /* Needed to get O_LARGEFILE definition */ #include #include #include #include #include #include #include #include #include int main(int argc, char *argv[]) { char buf; int fd; /* Check mount point is supplied */ if (argc != 2) { fprintf(stderr, "Usage: %s MOUNT\n", argv[0]); exit(EXIT_FAILURE); } printf("%s on %s\n", argv[0], argv[1]); /* Create the file descriptor for accessing the fanotify API */ fd = fanotify_init(FAN_CLOEXEC | FAN_CLASS_CONTENT | FAN_NONBLOCK, O_RDWR | O_LARGEFILE); if (fd == -1) { perror("fanotify_init"); exit(EXIT_FAILURE); } /* Loop marking all kinds of events and flush */ while (1) { #if 1 if (fanotify_mark(fd, FAN_MARK_ADD | FAN_MARK_MOUNT, FAN_ACCESS | FAN_MODIFY | FAN_OPEN_PERM | FAN_CLOSE | FAN_OPEN | FAN_ACCESS_PERM | FAN_ONDIR | FAN_EVENT_ON_CHILD, -1, argv[1]) == -1) perror("fanotify_mark add"); if (fanotify_mark(fd, FAN_MARK_FLUSH | FAN_MARK_MOUNT, 0, -1, argv[1]) == -1) perror("fanotify_mark flush mount"); #else if (fanotify_mark(fd, FAN_MARK_ADD | FAN_MARK_MOUNT, FAN_ACCESS | FAN_MODIFY | FAN_OPEN_PERM | FAN_CLOSE | FAN_OPEN | FAN_ACCESS_PERM | FAN_ONDIR | FAN_EVENT_ON_CHILD, -1, argv[1]) == -1) perror("fanotify_mark add"); if (fanotify_mark(fd, FAN_MARK_FLUSH, 0, -1, argv[1]) == -1) perror("fanotify_mark flush"); #endif } close(fd); exit(EXIT_SUCCESS); }