linux-kernel - Re: [syzbot] [ocfs2?] kernel BUG in ocfs2

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Message-ID: <0000000000000d9d23061fc6c1ad@google.com>
Date: Thu, 15 Aug 2024 23:06:03 -0700
From: syzbot <syzbot+5bdd4953bc58c8fbd6eb@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, lizhi.xu@...driver.com, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [ocfs2?] kernel BUG in ocfs2_iget

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: task hung in ocfs2_read_blocks_sync

INFO: task syz.0.15:5591 blocked for more than 143 seconds.
      Not tainted 6.11.0-rc3-syzkaller-00060-gd07b43284ab3-dirty #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.15        state:D stack:22832 pid:5591  tgid:5590  ppid:5536   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 io_schedule+0x8d/0x110 kernel/sched/core.c:7401
 bit_wait_io+0x12/0xd0 kernel/sched/wait_bit.c:209
 __wait_on_bit+0xb0/0x2f0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x1d5/0x260 kernel/sched/wait_bit.c:64
 wait_on_buffer include/linux/buffer_head.h:415 [inline]
 ocfs2_read_blocks_sync+0xc51/0xfe0 fs/ocfs2/buffer_head_io.c:183
 ocfs2_read_locked_inode fs/ocfs2/inode.c:503 [inline]
 ocfs2_iget+0xa3a/0x2120 fs/ocfs2/inode.c:159
 ocfs2_init_global_system_inodes+0xc6/0x730 fs/ocfs2/super.c:437
 ocfs2_initialize_super fs/ocfs2/super.c:2250 [inline]
 ocfs2_fill_super+0x3068/0x5880 fs/ocfs2/super.c:994
 mount_bdev+0x20a/0x2d0 fs/super.c:1679
 legacy_get_tree+0xee/0x190 fs/fs_context.c:662
 vfs_get_tree+0x90/0x2a0 fs/super.c:1800
 do_new_mount+0x2be/0xb40 fs/namespace.c:3472
 do_mount fs/namespace.c:3812 [inline]
 __do_sys_mount fs/namespace.c:4020 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3997
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7eff18d7b0ba
RSP: 002b:00007eff19a76e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007eff19a76ef0 RCX: 00007eff18d7b0ba
RDX: 0000000020004480 RSI: 00000000200044c0 RDI: 00007eff19a76eb0
RBP: 0000000020004480 R08: 00007eff19a76ef0 R09: 0000000002800400
R10: 0000000002800400 R11: 0000000000000246 R12: 00000000200044c0
R13: 00007eff19a76eb0 R14: 0000000000004481 R15: 00000000200001c0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/25:
 #0: ffffffff8e9382e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
 #0: ffffffff8e9382e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #0: ffffffff8e9382e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6626
2 locks held by kswapd0/72:
2 locks held by getty/4888:
 #0: ffff88801b6c10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000039b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6ac/0x1e00 drivers/tty/n_tty.c:2211
1 lock held by syz.0.15/5591:
 #0: ffff8880429de0e0 (&type->s_umount_key#52/1){+.+.}-{3:3}, at: alloc_super+0x221/0x9d0 fs/super.c:344

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 25 Comm: khungtaskd Not tainted 6.11.0-rc3-syzkaller-00060-gd07b43284ab3-dirty #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>


Tested on:

commit:         d07b4328 Merge tag 'for-linus' of git://git.kernel.org..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=12e04605980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7229118d88b4a71b
dashboard link: https://syzkaller.appspot.com/bug?extid=5bdd4953bc58c8fbd6eb
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14c516d5980000