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SubjectRe: WARNING: ODEBUG bug in f2fs_fill_super
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Date
Hi, Dmitry,

On 2019/2/20 23:12, Dmitry Vyukov wrote:
> On Mon, Aug 27, 2018 at 11:04 PM syzbot
> <syzbot+77ea19d309d4cdc55cc1@syzkaller.appspotmail.com> wrote:
>>
>> Hello,
>>
>> syzbot found the following crash on:
>>
>> HEAD commit: e27bc174c9c6 Add linux-next specific files for 20180824
>> git tree: linux-next
>> console output: https://syzkaller.appspot.com/x/log.txt?x=11c0034a400000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=28446088176757ea
>> dashboard link: https://syzkaller.appspot.com/bug?extid=77ea19d309d4cdc55cc1
>> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>>
>> Unfortunately, I don't have any reproducer for this crash yet.
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+77ea19d309d4cdc55cc1@syzkaller.appspotmail.com
>>
>> ------------[ cut here ]------------
>> ODEBUG: free active (active state 0) object type: percpu_counter
>> hint: (null)
>> WARNING: CPU: 1 PID: 18832 at lib/debugobjects.c:329
>> debug_print_object+0x16a/0x210 lib/debugobjects.c:326
>> Kernel panic - not syncing: panic_on_warn set ...
>
>
> Was this fixed by something?
> It happened a number of times, but then stopped after Oct 23 2018. Was it:
>
> commit 26b5a079197c8cb6725565968b7fd3299bd1877b
> Author: Sheng Yong <shengyong1@huawei.com>
> Date: Fri Oct 12 18:49:26 2018 +0800
> f2fs: cleanup dirty pages if recover failed
>
> which fixed some bugs in f2fs_fill_super?
>
During mount, f2fs tries to recover fsync-ed data of last unclean umount.
But if recover fails, f2fs_fill_super did not cleanup dirty pages which
have already recovered. This will trigger f2fs_bug_on later.

This patch fixes this by cleaning up these dirty pages and avoiding to
writing back these pages. After that, f2fs will retry mount without
recover.

But I don't see the reason of the debugobject warning, and not sure if the
patch fixed the warning :(

thanks,

>
>
>> CPU: 1 PID: 18832 Comm: syz-executor4 Not tainted 4.18.0-next-20180824+ #47
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> Google 01/01/2011
>> Call Trace:
>> __dump_stack lib/dump_stack.c:77 [inline]
>> dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
>> panic+0x238/0x4e7 kernel/panic.c:184
>> __warn.cold.8+0x163/0x1ba kernel/panic.c:536
>> report_bug+0x252/0x2d0 lib/bug.c:186
>> fixup_bug arch/x86/kernel/traps.c:178 [inline]
>> do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
>> do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
>> invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:996
>> RIP: 0010:debug_print_object+0x16a/0x210 lib/debugobjects.c:326
>> Code: 3a 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 92 00 00 00 48 8b 14 dd
>> 20 e5 3a 87 4c 89 f6 48 c7 c7 c0 da 3a 87 e8 26 ec e3 fd <0f> 0b 83 05 a9
>> 49 28 05 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f
>> RSP: 0018:ffff8801a9a97360 EFLAGS: 00010082
>> RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffc90012037000
>> RDX: 000000000002cd2b RSI: ffffffff8163b051 RDI: 0000000000000001
>> RBP: ffff8801a9a973a0 R08: ffff8801c1f76100 R09: ffffed003b623eca
>> R10: ffffed003b623eca R11: ffff8801db11f657 R12: 0000000000000001
>> R13: ffffffff882b7ae0 R14: ffffffff873adf60 R15: 0000000000000000
>> __debug_check_no_obj_freed lib/debugobjects.c:786 [inline]
>> debug_check_no_obj_freed+0x3b2/0x595 lib/debugobjects.c:818
>> kfree+0xc7/0x210 mm/slab.c:3812
>> f2fs_fill_super+0xe1a/0x8150 fs/f2fs/super.c:3147
>> mount_bdev+0x314/0x3e0 fs/super.c:1347
>> f2fs_mount+0x3c/0x50 fs/f2fs/super.c:3161
>> legacy_get_tree+0x131/0x460 fs/fs_context.c:732
>> vfs_get_tree+0x1cb/0x5c0 fs/super.c:1746
>> do_new_mount fs/namespace.c:2627 [inline]
>> do_mount+0x6f9/0x1e30 fs/namespace.c:2951
>> ksys_mount+0x12d/0x140 fs/namespace.c:3167
>> __do_sys_mount fs/namespace.c:3181 [inline]
>> __se_sys_mount fs/namespace.c:3178 [inline]
>> __x64_sys_mount+0xbe/0x150 fs/namespace.c:3178
>> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>> RIP: 0033:0x459aba
>> Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 bd 8a fb ff c3 66 2e 0f
>> 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff
>> ff 0f 83 9a 8a fb ff c3 66 0f 1f 84 00 00 00 00 00
>> RSP: 002b:00007f16f9937a88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
>> RAX: ffffffffffffffda RBX: 00007f16f9937b30 RCX: 0000000000459aba
>> RDX: 00007f16f9937ad0 RSI: 0000000020000100 RDI: 00007f16f9937af0
>> RBP: 0000000020000100 R08: 00007f16f9937b30 R09: 00007f16f9937ad0
>> R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000003
>> R13: 0000000000000000 R14: 00000000004c9c12 R15: 0000000000000000
>>
>> ======================================================
>> WARNING: possible circular locking dependency detected
>> 4.18.0-next-20180824+ #47 Not tainted
>> ------------------------------------------------------
>> syz-executor4/18832 is trying to acquire lock:
>> 00000000cd8e7eb7 ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70
>> kernel/locking/semaphore.c:136
>>
>> but task is already holding lock:
>> 0000000046ad1dd4 (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed
>> lib/debugobjects.c:777 [inline]
>> 0000000046ad1dd4 (&obj_hash[i].lock){-.-.}, at:
>> debug_check_no_obj_freed+0x16c/0x595 lib/debugobjects.c:818
>>
>> which lock already depends on the new lock.
>>
>>
>> the existing dependency chain (in reverse order) is:
>>
>> -> #3 (&obj_hash[i].lock){-.-.}:
>> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
>> _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152
>> __debug_object_init+0x127/0x12e0 lib/debugobjects.c:384
>> debug_object_init+0x16/0x20 lib/debugobjects.c:432
>> debug_hrtimer_init kernel/time/hrtimer.c:410 [inline]
>> debug_init kernel/time/hrtimer.c:458 [inline]
>> hrtimer_init+0x97/0x410 kernel/time/hrtimer.c:1308
>> init_dl_task_timer+0x1b/0x50 kernel/sched/deadline.c:1057
>> __sched_fork+0x2ae/0x590 kernel/sched/core.c:2160
>> init_idle+0x75/0x740 kernel/sched/core.c:5377
>> sched_init+0xbee/0xcbd kernel/sched/core.c:6060
>> start_kernel+0x47d/0x94e init/main.c:602
>> x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452
>> x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433
>> secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242
>>
>> -> #2 (&rq->lock){-.-.}:
>> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
>> _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144
>> rq_lock kernel/sched/sched.h:1821 [inline]
>> task_fork_fair+0x93/0x680 kernel/sched/fair.c:9574
>> sched_fork+0x44b/0xbd0 kernel/sched/core.c:2353
>> copy_process+0x235e/0x7af0 kernel/fork.c:1840
>> _do_fork+0x1ca/0x1170 kernel/fork.c:2169
>> kernel_thread+0x34/0x40 kernel/fork.c:2228
>> rest_init+0x22/0xe4 init/main.c:408
>> start_kernel+0x913/0x94e init/main.c:739
>> x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452
>> x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433
>> secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242
>>
>> -> #1 (&p->pi_lock){-.-.}:
>> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
>> _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152
>> try_to_wake_up+0xd2/0x1250 kernel/sched/core.c:1960
>> wake_up_process+0x10/0x20 kernel/sched/core.c:2123
>> __up.isra.1+0x1c0/0x2a0 kernel/locking/semaphore.c:262
>> up+0x13c/0x1c0 kernel/locking/semaphore.c:187
>> __up_console_sem+0xbe/0x1b0 kernel/printk/printk.c:245
>> console_unlock+0x506/0x10d0 kernel/printk/printk.c:2430
>> con_install+0x34e/0x420 drivers/tty/vt/vt.c:3241
>> tty_driver_install_tty drivers/tty/tty_io.c:1224 [inline]
>> tty_init_dev+0xfd/0x460 drivers/tty/tty_io.c:1324
>> tty_open_by_driver drivers/tty/tty_io.c:1959 [inline]
>> tty_open+0x692/0xb30 drivers/tty/tty_io.c:2007
>> chrdev_open+0x25a/0x770 fs/char_dev.c:417
>> do_dentry_open+0x49c/0x1140 fs/open.c:771
>> vfs_open+0xa0/0xd0 fs/open.c:880
>> do_last fs/namei.c:3418 [inline]
>> path_openat+0x12fb/0x5300 fs/namei.c:3534
>> do_filp_open+0x255/0x380 fs/namei.c:3564
>> do_sys_open+0x584/0x720 fs/open.c:1063
>> __do_sys_open fs/open.c:1081 [inline]
>> __se_sys_open fs/open.c:1076 [inline]
>> __x64_sys_open+0x7e/0xc0 fs/open.c:1076
>> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>>
>> -> #0 ((console_sem).lock){-.-.}:
>> lock_acquire+0x1e4/0x4f0 kernel/locking/lockdep.c:3901
>> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
>> _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152
>> down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
>> __down_trylock_console_sem+0xae/0x200 kernel/printk/printk.c:228
>> console_trylock+0x15/0xa0 kernel/printk/printk.c:2249
>> console_trylock_spinning kernel/printk/printk.c:1651 [inline]
>> vprintk_emit+0x31f/0x910 kernel/printk/printk.c:1926
>> vprintk_default+0x28/0x30 kernel/printk/printk.c:1968
>> vprintk_func+0x7a/0x117 kernel/printk/printk_safe.c:398
>> printk+0xa7/0xcf kernel/printk/printk.c:2001
>> __warn_printk+0x8c/0xe0 kernel/panic.c:590
>> debug_print_object+0x16a/0x210 lib/debugobjects.c:326
>> __debug_check_no_obj_freed lib/debugobjects.c:786 [inline]
>> debug_check_no_obj_freed+0x3b2/0x595 lib/debugobjects.c:818
>> kfree+0xc7/0x210 mm/slab.c:3812
>> f2fs_fill_super+0xe1a/0x8150 fs/f2fs/super.c:3147
>> mount_bdev+0x314/0x3e0 fs/super.c:1347
>> f2fs_mount+0x3c/0x50 fs/f2fs/super.c:3161
>> legacy_get_tree+0x131/0x460 fs/fs_context.c:732
>> vfs_get_tree+0x1cb/0x5c0 fs/super.c:1746
>> do_new_mount fs/namespace.c:2627 [inline]
>> do_mount+0x6f9/0x1e30 fs/namespace.c:2951
>> ksys_mount+0x12d/0x140 fs/namespace.c:3167
>> __do_sys_mount fs/namespace.c:3181 [inline]
>> __se_sys_mount fs/namespace.c:3178 [inline]
>> __x64_sys_mount+0xbe/0x150 fs/namespace.c:3178
>> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>>
>> other info that might help us debug this:
>>
>> Chain exists of:
>> (console_sem).lock --> &rq->lock --> &obj_hash[i].lock
>>
>> Possible unsafe locking scenario:
>>
>> CPU0 CPU1
>> ---- ----
>> lock(&obj_hash[i].lock);
>> lock(&rq->lock);
>> lock(&obj_hash[i].lock);
>> lock((console_sem).lock);
>>
>> *** DEADLOCK ***
>>
>> 2 locks held by syz-executor4/18832:
>> #0: 000000002b55bbcc (&fc->fs_type->s_umount_key#49/1){+.+.}, at:
>> alloc_super+0x25e/0xb20 fs/super.c:225
>> #1: 0000000046ad1dd4 (&obj_hash[i].lock){-.-.}, at:
>> __debug_check_no_obj_freed lib/debugobjects.c:777 [inline]
>> #1: 0000000046ad1dd4 (&obj_hash[i].lock){-.-.}, at:
>> debug_check_no_obj_freed+0x16c/0x595 lib/debugobjects.c:818
>>
>> stack backtrace:
>> CPU: 1 PID: 18832 Comm: syz-executor4 Not tainted 4.18.0-next-20180824+ #47
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> Google 01/01/2011
>> Call Trace:
>> __dump_stack lib/dump_stack.c:77 [inline]
>> dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
>> print_circular_bug.isra.34.cold.55+0x1bd/0x27d
>> kernel/locking/lockdep.c:1222
>> check_prev_add kernel/locking/lockdep.c:1862 [inline]
>> check_prevs_add kernel/locking/lockdep.c:1975 [inline]
>> validate_chain kernel/locking/lockdep.c:2416 [inline]
>> __lock_acquire+0x3449/0x5020 kernel/locking/lockdep.c:3412
>> lock_acquire+0x1e4/0x4f0 kernel/locking/lockdep.c:3901
>> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
>> _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152
>> down_trylock+0x13/0x70 kernel/locking/semaphore.c:136
>> __down_trylock_console_sem+0xae/0x200 kernel/printk/printk.c:228
>> console_trylock+0x15/0xa0 kernel/printk/printk.c:2249
>> console_trylock_spinning kernel/printk/printk.c:1651 [inline]
>> vprintk_emit+0x31f/0x910 kernel/printk/printk.c:1926
>> vprintk_default+0x28/0x30 kernel/printk/printk.c:1968
>> vprintk_func+0x7a/0x117 kernel/printk/printk_safe.c:398
>> printk+0xa7/0xcf kernel/printk/printk.c:2001
>> __warn_printk+0x8c/0xe0 kernel/panic.c:590
>> debug_print_object+0x16a/0x210 lib/debugobjects.c:326
>> __debug_check_no_obj_freed lib/debugobjects.c:786 [inline]
>> debug_check_no_obj_freed+0x3b2/0x595 lib/debugobjects.c:818
>> kfree+0xc7/0x210 mm/slab.c:3812
>> f2fs_fill_super+0xe1a/0x8150 fs/f2fs/super.c:3147
>> mount_bdev+0x314/0x3e0 fs/super.c:1347
>> f2fs_mount+0x3c/0x50 fs/f2fs/super.c:3161
>> legacy_get_tree+0x131/0x460 fs/fs_context.c:732
>> vfs_get_tree+0x1cb/0x5c0 fs/super.c:1746
>> do_new_mount fs/namespace.c:2627 [inline]
>> do_mount+0x6f9/0x1e30 fs/namespace.c:2951
>> ksys_mount+0x12d/0x140 fs/namespace.c:3167
>> __do_sys_mount fs/namespace.c:3181 [inline]
>> __se_sys_mount fs/namespace.c:3178 [inline]
>> __x64_sys_mount+0xbe/0x150 fs/namespace.c:3178
>> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>> RIP: 0033:0x459aba
>> Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 bd 8a fb ff c3 66 2e 0f
>> 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff
>> ff 0f 83 9a 8a fb ff c3 66 0f 1f 84 00 00 00 00 00
>> RSP: 002b:00007f16f9937a88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
>> RAX: ffffffffffffffda RBX: 00007f16f9937b30 RCX: 0000000000459aba
>> RDX: 00007f16f9937ad0 RSI: 0000000020000100 RDI: 00007f16f9937af0
>> RBP: 0000000020000100 R08: 00007f16f9937b30 R09: 00007f16f9937ad0
>> R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000003
>> R13: 0000000000000000 R14: 00000000004c9c12 R15: 0000000000000000
>> Dumping ftrace buffer:
>> ---------------------------------
>> syz-exec-23595 1...2 1079757271us : 0: }D
>> syz-exec-23595 1..s3 1079757464us : 0: }D
>> ---------------------------------
>> Kernel Offset: disabled
>> Rebooting in 86400 seconds..
>>
>>
>> ---
>> This bug is generated by a bot. It may contain errors.
>> See https://goo.gl/tpsmEJ for more information about syzbot.
>> syzbot engineers can be reached at syzkaller@googlegroups.com.
>>
>> syzbot will keep track of this bug report. See:
>> https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
>> syzbot.
>>
>> --
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>> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/0000000000009e76240574711017%40google.com.
>> For more options, visit https://groups.google.com/d/optout.
>
> .
>

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