Re: [syzbot] INFO: task hung in gfs2_gl_hash_clear (3)

From: Wangshaobo (bobo)
Date: Wed Nov 30 2022 - 05:02:06 EST


Fix missing call gfs2_make_fs_ro() int gfs2_put_super()

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

b7b275e60bcd

--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -584,9 +584,7 @@ static void gfs2_put_super(struct super_block *sb)
}
spin_unlock(&sdp->sd_jindex_spin);

- if (!sb_rdonly(sb)) {
- gfs2_make_fs_ro(sdp);
- }
+ gfs2_make_fs_ro(sdp);
WARN_ON(gfs2_withdrawing(sdp));

/* At this point, we're through modifying the disk */
--

在 2022/11/29 16:32, syzbot 写道:
Hello,

syzbot found the following issue on:

HEAD commit: 6d464646530f Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=167aebbb880000
kernel config: https://syzkaller.appspot.com/x/.config?x=54b747d981acc7b7
dashboard link: https://syzkaller.appspot.com/bug?extid=ed7d0f71a89e28557a77
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16467353880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=168c3d03880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d75f5f77b3a3/disk-6d464646.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9382f86e4d95/vmlinux-6d464646.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cf2b5f0d51dd/Image-6d464646.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/04ef22130add/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ed7d0f71a89e28557a77@xxxxxxxxxxxxxxxxxxxxxxxxx

INFO: task syz-executor888:3126 blocked for more than 143 seconds.
Not tainted 6.1.0-rc6-syzkaller-32662-g6d464646530f #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor888 state:D stack:0 pid:3126 ppid:3124 flags:0x00000000
Call trace:
__switch_to+0x180/0x298 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5209 [inline]
__schedule+0x408/0x594 kernel/sched/core.c:6521
schedule+0x64/0xa4 kernel/sched/core.c:6597
schedule_timeout+0x108/0x1b4 kernel/time/timer.c:1935
gfs2_gl_hash_clear+0xd4/0x1b0 fs/gfs2/glock.c:2263
gfs2_put_super+0x318/0x390 fs/gfs2/super.c:620
generic_shutdown_super+0x94/0x198 fs/super.c:492
kill_block_super+0x30/0x78 fs/super.c:1428
gfs2_kill_sb+0x68/0x78
deactivate_locked_super+0x70/0xe8 fs/super.c:332
deactivate_super+0xd0/0xd4 fs/super.c:363
cleanup_mnt+0x184/0x1c0 fs/namespace.c:1186
__cleanup_mnt+0x20/0x30 fs/namespace.c:1193
task_work_run+0x100/0x148 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
do_notify_resume+0x174/0x1f0 arch/arm64/kernel/signal.c:1127
prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
el0_svc+0x9c/0x150 arch/arm64/kernel/entry-common.c:638
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/11:
#0: ffff80000d4a4768 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x3c/0x450 kernel/rcu/tasks.h:507
1 lock held by rcu_tasks_trace/12:
#0: ffff80000d4a4db8 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x3c/0x450 kernel/rcu/tasks.h:507
1 lock held by khungtaskd/27:
#0: ffff80000d4a4640 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x4/0x48 include/linux/rcupdate.h:303
2 locks held by getty/2759:
#0: ffff0000c7d7e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x28/0x58 drivers/tty/tty_ldisc.c:244
#1: ffff80000f6be2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x19c/0x89c drivers/tty/n_tty.c:2177
1 lock held by syz-executor888/3126:
#0: ffff0000cae680e0 (&type->s_umount_key#41){+.+.}-{3:3}, at: deactivate_super+0xc8/0xd4 fs/super.c:362

=============================================



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