Re: [syzbot] [btrfs?] kernel BUG in compress_file_range

[Qu Wenruo <wqu@suse.com>]

在 2026/8/1 09:55, syzbot 写道:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    f5098b6bae76 Linux 7.2-rc5
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17829632580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=b7079b368dcec295
> dashboard link: https://syzkaller.appspot.com/bug?extid=db04810ad3d91a0a4697
> compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/b18067cdf26c/disk-f5098b6b.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/2b364c33a0f2/vmlinux-f5098b6b.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/2dfce6f90a4d/bzImage-f5098b6b.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+db04810ad3d91a0a4697@syzkaller.appspotmail.com
> 
> ------------[ cut here ]------------
> kernel BUG at fs/btrfs/inode.c:977!

This one is from the BUG_ON() of memory allocation.

We need to properly handle the memory allocation error.

Thanks for the report,
Qu

> Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
> CPU: 1 UID: 0 PID: 752 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
> Workqueue: btrfs-delalloc btrfs_work_helper
> RIP: 0010:compress_file_range+0x1e27/0x2430 fs/btrfs/inode.c:977
> Code: af 0c 01 e8 db 39 8a fd e9 55 fd ff ff e8 51 fc ae fd 48 c7 c6 20 1d 28 8c 48 89 df e8 a2 ab ff fd 90 0f 0b e8 3a fc ae fd 90 <0f> 0b e8 32 fc ae fd 48 8b 54 24 78 48 b8 00 00 00 00 00 fc ff df
> RSP: 0018:ffffc9000454fac0 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: 0000000000020000 RCX: ffffffff845b3929
> RDX: ffff8880272e9f00 RSI: ffffffff845b42e6 RDI: ffff8880272e9f00
> RBP: 00000000fffffff4 R08: 0000000000000005 R09: 0000000000000000
> R10: 00000000fffffff4 R11: 0000000000000000 R12: 000000000001ffff
> R13: 0000000000000fea R14: ffff888068d78000 R15: 0000000000000016
> FS:  0000000000000000(0000) GS:ffff888123ede000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000110c3ea6fb CR3: 000000001cbb3000 CR4: 0000000000350ef0
> Call Trace:
>   <TASK>
>   btrfs_work_helper+0x214/0xc70 fs/btrfs/async-thread.c:312
>   process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
>   process_scheduled_works kernel/workqueue.c:3405 [inline]
>   worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
>   kthread+0x370/0x450 kernel/kthread.c:436
>   ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
>   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>   </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:compress_file_range+0x1e27/0x2430 fs/btrfs/inode.c:977
> Code: af 0c 01 e8 db 39 8a fd e9 55 fd ff ff e8 51 fc ae fd 48 c7 c6 20 1d 28 8c 48 89 df e8 a2 ab ff fd 90 0f 0b e8 3a fc ae fd 90 <0f> 0b e8 32 fc ae fd 48 8b 54 24 78 48 b8 00 00 00 00 00 fc ff df
> RSP: 0018:ffffc9000454fac0 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: 0000000000020000 RCX: ffffffff845b3929
> RDX: ffff8880272e9f00 RSI: ffffffff845b42e6 RDI: ffff8880272e9f00
> RBP: 00000000fffffff4 R08: 0000000000000005 R09: 0000000000000000
> R10: 00000000fffffff4 R11: 0000000000000000 R12: 000000000001ffff
> R13: 0000000000000fea R14: ffff888068d78000 R15: 0000000000000016
> FS:  0000000000000000(0000) GS:ffff888123dde000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f16bf558fb0 CR3: 000000007c548000 CR4: 0000000000350ef0
> 
> 
> ---
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