Re: [syzbot] WARNING in __find_get_block

[Dmitry Vyukov]

On Sat, 1 Oct 2022 at 15:50, syzbot
<syzbot+250b054f84ffcf12d7f1@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    c3e0e1e23c70 Merge tag 'irq_urgent_for_v6.0' of git://git...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=10bbbb9c880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=ba0d23aa7e1ffaf5
> dashboard link: https://syzkaller.appspot.com/bug?extid=250b054f84ffcf12d7f1
> compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/e7f1f925f94e/disk-c3e0e1e2.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/830dabeedf0d/vmlinux-c3e0e1e2.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+250b054f84ffcf12d7f1@xxxxxxxxxxxxxxxxxxxxxxxxx

+fat maintainers

> ------------[ cut here ]------------
> VFS: brelse: Trying to free free buffer
> WARNING: CPU: 1 PID: 6477 at fs/buffer.c:1145 __brelse fs/buffer.c:1145 [inline]
> WARNING: CPU: 1 PID: 6477 at fs/buffer.c:1145 brelse include/linux/buffer_head.h:327 [inline]
> WARNING: CPU: 1 PID: 6477 at fs/buffer.c:1145 bh_lru_install fs/buffer.c:1259 [inline]
> WARNING: CPU: 1 PID: 6477 at fs/buffer.c:1145 __find_get_block+0xfe9/0x1110 fs/buffer.c:1309
> Modules linked in:
> CPU: 0 PID: 6477 Comm: syz-executor.1 Not tainted 6.0.0-rc7-syzkaller-00081-gc3e0e1e23c70 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
> RIP: 0010:__brelse fs/buffer.c:1145 [inline]
> RIP: 0010:brelse include/linux/buffer_head.h:327 [inline]
> RIP: 0010:bh_lru_install fs/buffer.c:1259 [inline]
> RIP: 0010:__find_get_block+0xfe9/0x1110 fs/buffer.c:1309
> Code: 8e ff e8 5a f5 94 ff fb e9 02 f3 ff ff e8 5f 48 8e ff e9 f8 f2 ff ff e8 55 48 8e ff 48 c7 c7 a0 9a 9d 8a 31 c0 e8 27 d5 56 ff <0f> 0b e9 de f2 ff ff 44 89 f9 80 e1 07 38 c1 0f 8c a1 f3 ff ff 4c
> RSP: 0018:ffffc90004a9f880 EFLAGS: 00010246
> RAX: 533f0fab2aa63200 RBX: 0000000000000000 RCX: 0000000000040000
> RDX: ffffc900054e9000 RSI: 000000000000bd65 RDI: 000000000000bd66
> RBP: ffffc90004a9f9e0 R08: ffffffff816bd38d R09: ffffed1017364f14
> R10: ffffed1017364f14 R11: 1ffff11017364f13 R12: 1ffff11017366bae
> R13: ffff8880292d6828 R14: ffff88802901ee80 R15: ffff8880290195d0
> FS:  00007fc26c747700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000110f33724b CR3: 000000007c6dd000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  __getblk_gfp+0x2d/0x290 fs/buffer.c:1329
>  sb_getblk include/linux/buffer_head.h:363 [inline]
>  fat_zeroed_cluster+0x18b/0x8c0 fs/fat/dir.c:1092
>  fat_alloc_new_dir+0x7c6/0xc90 fs/fat/dir.c:1185
>  vfat_mkdir+0x15a/0x410 fs/fat/namei_vfat.c:859
>  vfs_mkdir+0x3b3/0x590 fs/namei.c:4013
>  do_mkdirat+0x279/0x550 fs/namei.c:4038
>  __do_sys_mkdirat fs/namei.c:4053 [inline]
>  __se_sys_mkdirat fs/namei.c:4051 [inline]
>  __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4051
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7fc26b68a5a9
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007fc26c747168 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
> RAX: ffffffffffffffda RBX: 00007fc26b7abf80 RCX: 00007fc26b68a5a9
> RDX: 0000000000000004 RSI: 0000000020000040 RDI: 0000000000000005
> RBP: 00007fc26b6e5580 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ffdd6d66b0f R14: 00007fc26c747300 R15: 0000000000022000
>  </TASK>
>
>
> ---
> This report 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@xxxxxxxxxxxxxxxx.
>
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>
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