Re: WARNING in disk_release

[Christoph Hellwig]

On Wed, Oct 27, 2021 at 09:31:25AM +0800, Hao Sun wrote:
> git tree: upstream
> console output:
> https://drive.google.com/file/d/1657ywLUsQk5HIV6DDfHHJydz_PPTdr6V/view?usp=sharing
> kernel config: https://drive.google.com/file/d/12PUnxIM1EPBgW4ZJmI7WJBRaY1lA83an/view?usp=sharing
> C reproducer: https://drive.google.com/file/d/1PV2erZe9uWRr7cGc3BLKkwBwaSVjksLc/view?usp=sharing
> Syzlang reproducer:
> https://drive.google.com/file/d/1A921cPkylfbW2cYCvbtImODZXd0mbg3l/view?usp=sharing

Please fix your setup to upload the actual text files directly.  This
just gives a login page and doesn't work with wget/curl and also fails
to actually work in firefox.

What is so hard in using some non-broken webspace these days?

> If you fix this issue, please add the following tag to the commit:
> Reported-by: Hao Sun <sunhao.th@xxxxxxxxx>
> 
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 32158 at block/genhd.c:1081

Anyway, this is the new debug check to detect a final put of a disk
that is not unregistered yet.  So it did made some pre-existing issue
show up.

> disk_release+0x1c0/0x230 block/genhd.c:1081
> Modules linked in:
> CPU: 0 PID: 32158 Comm: syz-executor Not tainted 5.15.0-rc6 #4
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> 1.13.0-1ubuntu1.1 04/01/2014
> RIP: 0010:disk_release+0x1c0/0x230 block/genhd.c:1081
> Code: 00 00 00 00 fc ff df 48 8d 7b 28 48 89 fa 48 c1 ea 03 80 3c 02
> 00 75 4e 48 8b 7b 28 5b 5d 41 5c e9 b5 8b ff fd e8 20 2e a5 fd <0f> 0b
> e9 06 ff ff ff e8 34 be ec fd e9 2b ff ff ff e8 2a be ec fd
> RSP: 0018:ffffc900019efda0 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: ffff88801a718800 RCX: ffff888113811c80
> RDX: 0000000000000000 RSI: ffff888113811c80 RDI: 0000000000000002
> RBP: ffff88801a718880 R08: ffffffff83d130a0 R09: ffffed100c7c6542
> R10: ffff888063e32a0b R11: ffffed100c7c6541 R12: ffff888103988688
> R13: 0000000000000002 R14: ffff8880194fa4d8 R15: ffff888014acee00
> FS:  0000555555d8a940(0000) GS:ffff888135c00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007efdcf048820 CR3: 000000010cd05000 CR4: 0000000000350ee0
> Call Trace:
>  device_release+0x9f/0x240 drivers/base/core.c:2232
>  kobject_cleanup lib/kobject.c:705 [inline]
>  kobject_release lib/kobject.c:736 [inline]
>  kref_put include/linux/kref.h:65 [inline]
>  kobject_put+0x1c8/0x530 lib/kobject.c:753
>  put_device+0x1b/0x30 drivers/base/core.c:3503
>  blkdev_close+0x8d/0xb0 block/fops.c:460
>  __fput+0x288/0x9f0 fs/file_table.c:280
>  task_work_run+0xe0/0x1a0 kernel/task_work.c:164
>  tracehook_notify_resume include/linux/tracehook.h:189 [inline]
>  exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
>  exit_to_user_mode_prepare+0x28d/0x2a0 kernel/entry/common.c:207
>  __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
>  syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
>  do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x7efdcefd62cb
> Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c
> 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d
> 00 f0 ff ff 77 2f 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
> RSP: 002b:00007ffdc6a50700 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
> RAX: 0000000000000000 RBX: 00007ffdc6a50770 RCX: 00007efdcefd62cb
> RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003
> RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffdc6a505b0
> R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
> R13: 0000000000000003 R14: 00007ffdc6a507b0 R15: 00007ffdc6a5076c
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