Re: [syzbot] [dri?] WARNING in drm_prime_destroy_file_private (2)

Qi Zheng
2023-12-28T02:57:58Z

On 2023/12/28 04:51, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 5254c0cbc92d Merge tag 'block-6.7-2023-12-22' of git://git..
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=10cc6995e80000
> kernel config: https://syzkaller.appspot.com/x/.config?x=314e9ad033a7d3a7
> dashboard link: https://syzkaller.appspot.com/bug?extid=59dcc2e7283a6f5f5ba1
> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13e35809e80000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=155d5fd6e80000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/ebe09a5995ee/disk-5254c0cb.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/02178d7f5f98/vmlinux-5254c0cb.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/12307f47d87c/bzImage-5254c0cb.xz
>
> The issue was bisected to:
>
> commit ea4452de2ae987342fadbdd2c044034e6480daad
> Author: Qi Zheng <zhengqi.arch@bytedance.com>
> Date: Fri Nov 18 10:00:11 2022 +0000
>
> mm: fix unexpected changes to {failslab|fail_page_alloc}.attr
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13027f76e80000
> final oops: https://syzkaller.appspot.com/x/report.txt?x=10827f76e80000
> console output: https://syzkaller.appspot.com/x/log.txt?x=17027f76e80000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+59dcc2e7283a6f5f5ba1@syzkaller.appspotmail.com
> Fixes: ea4452de2ae9 ("mm: fix unexpected changes to {failslab|fail_page_alloc}.attr")
>
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007efe98069194
> R13: 00007efe97fd2210 R14: 0000000000000002 R15: 6972642f7665642f
> </TASK>
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 5107 at drivers/gpu/drm/drm_prime.c:227 drm_prime_destroy_file_private+0x43/0x60 drivers/gpu/drm/drm_prime.c:227

The warning is caused by !RB_EMPTY_ROOT(&prime_fpriv->dmabufs):

drm_prime_destroy_file_private
--> WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));

It seems irrelevant to the logic of fault injection. So I don't see
why the commit ea4452de2ae9 can cause this warning. :(

> Modules linked in:
> CPU: 0 PID: 5107 Comm: syz-executor227 Not tainted 6.7.0-rc6-syzkaller-00248-g5254c0cbc92d #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
> RIP: 0010:drm_prime_destroy_file_private+0x43/0x60 drivers/gpu/drm/drm_prime.c:227
> Code: 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 21 48 8b 83 90 00 00 00 48 85 c0 75 06 5b e9 13 f1 93 fc e8 0e f1 93 fc 90 <0f> 0b 90 5b e9 04 f1 93 fc e8 3f 9b ea fc eb d8 66 66 2e 0f 1f 84
> RSP: 0018:ffffc90003bdf9e0 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: ffff888019f28378 RCX: ffffc90003bdf9b0
> RDX: ffff888018ff9dc0 RSI: ffffffff84f380c2 RDI: ffff888019f28408
> RBP: ffff888019f28000 R08: 0000000000000001 R09: 0000000000000001
> R10: ffffffff8f193a57 R11: 0000000000000000 R12: ffff88814829a000
> R13: ffff888019f282a8 R14: ffff88814829a068 R15: ffff88814829a0a0
> FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007efe98050410 CR3: 000000006d1ff000 CR4: 0000000000350ef0
> Call Trace:
> <TASK>
> drm_file_free.part.0+0x738/0xb90 drivers/gpu/drm/drm_file.c:290
> drm_file_free drivers/gpu/drm/drm_file.c:247 [inline]
> drm_close_helper.isra.0+0x180/0x1f0 drivers/gpu/drm/drm_file.c:307
> drm_release+0x22a/0x4f0 drivers/gpu/drm/drm_file.c:494
> __fput+0x270/0xb70 fs/file_table.c:394
> task_work_run+0x14d/0x240 kernel/task_work.c:180
> exit_task_work include/linux/task_work.h:38 [inline]
> do_exit+0xa8a/0x2ad0 kernel/exit.c:869
> do_group_exit+0xd4/0x2a0 kernel/exit.c:1018
> get_signal+0x23b5/0x2790 kernel/signal.c:2904
> arch_do_signal_or_restart+0x90/0x7f0 arch/x86/kernel/signal.c:309
> exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
> exit_to_user_mode_prepare+0x121/0x240 kernel/entry/common.c:204
> __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
> syscall_exit_to_user_mode+0x1e/0x60 kernel/entry/common.c:296
> do_syscall_64+0x4d/0x110 arch/x86/entry/common.c:89
> entry_SYSCALL_64_after_hwframe+0x63/0x6b
> RIP: 0033:0x7efe98014769
> Code: Unable to access opcode bytes at 0x7efe9801473f.
> RSP: 002b:00007efe97fd2208 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
> RAX: fffffffffffffe00 RBX: 00007efe9809c408 RCX: 00007efe98014769
> RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007efe9809c408
> RBP: 00007efe9809c400 R08: 0000000000003131 R09: 0000000000003131
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007efe98069194
> R13: 00007efe97fd2210 R14: 0000000000000002 R15: 6972642f7665642f
> </TASK>
>
>
> ---
> This report is generated by a bot. It may contain errors.
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