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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Tue, 4 Apr 2023 09:52:50 +0200
Message-ID: <CACT4Y+Z+aSLaJXO_vn00Yjt2HuH0CYb7WbSR6gfcOnK=wCSjCw@mail.gmail.com>
Subject: Re: [syzbot] [dri?] general protection fault in drm_crtc_next_vblank_start
To:     Rob Clark <robdclark@chromium.org>
Cc:     syzbot <syzbot+54280c5aea19802490b5@syzkaller.appspotmail.com>,
        airlied@gmail.com, airlied@redhat.com, christian.koenig@amd.com,
        daniel.vetter@ffwll.ch, daniel@ffwll.ch,
        dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
        linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
        sean@poorly.run, sumit.semwal@linaro.org,
        syzkaller-bugs@googlegroups.com, tzimmermann@suse.de
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On Mon, 3 Apr 2023 at 18:26, Rob Clark <robdclark@chromium.org> wrote:
>
> On Mon, Apr 3, 2023 at 12:57=E2=80=AFAM syzbot
> <syzbot+54280c5aea19802490b5@syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    a6d9e3034536 Add linux-next specific files for 20230330
> > git tree:       linux-next
> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=3D1001d1cdc80=
000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=3Daceb117f792=
4508e
> > dashboard link: https://syzkaller.appspot.com/bug?extid=3D54280c5aea198=
02490b5
> > compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binu=
tils for Debian) 2.35.2
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D13435a2ec=
80000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=3D139c9c21c80=
000
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/ec1f900ea929/d=
isk-a6d9e303.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/fabbf89c0d22/vmli=
nux-a6d9e303.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/1ed05d6192fa=
/bzImage-a6d9e303.xz
> >
> > The issue was bisected to:
> >
> > commit d39e48ca80c0960b039cb38633957f0040f63e1a
> > Author: Rob Clark <robdclark@chromium.org>
> > Date:   Fri Sep 3 18:47:54 2021 +0000
> >
> >     drm/atomic-helper: Set fence deadline for vblank
> >
>
> should be fixed by https://patchwork.freedesktop.org/series/115992/

Let's tell syzbot about the fix so that it reports similar crashes in futur=
e:

#syz fix: drm/vblank: Fix for drivers that do not drm_vblank_init()

> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=3D12d260c9=
c80000
> > final oops:     https://syzkaller.appspot.com/x/report.txt?x=3D11d260c9=
c80000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=3D16d260c9c80=
000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the co=
mmit:
> > Reported-by: syzbot+54280c5aea19802490b5@syzkaller.appspotmail.com
> > Fixes: d39e48ca80c0 ("drm/atomic-helper: Set fence deadline for vblank"=
)
> >
> > [drm] Initialized udl 0.0.1 20120220 for 1-1:0.0 on minor 2
> > [drm] Initialized udl on minor 2
> > udl 1-1:0.0: [drm] *ERROR* Read EDID byte 0 failed err ffffffb9
> > udl 1-1:0.0: [drm] Cannot find any crtc or sizes
> > general protection fault, probably for non-canonical address 0xdffffc00=
00000028: 0000 [#1] PREEMPT SMP KASAN
> > KASAN: null-ptr-deref in range [0x0000000000000140-0x0000000000000147]
> > CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.3.0-rc4-next-20230330-syz=
kaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS=
 Google 03/02/2023
> > Workqueue: usb_hub_wq hub_event
> > RIP: 0010:drm_crtc_next_vblank_start+0xb3/0x2b0 drivers/gpu/drm/drm_vbl=
ank.c:1003
> > Code: e8 01 00 00 48 69 db 38 02 00 00 48 b8 00 00 00 00 00 fc ff df 49=
 03 9d 38 03 00 00 4c 8d ab 44 01 00 00 4c 89 ea 48 c1 ea 03 <0f> b6 14 02 =
4c 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 67
> > RSP: 0018:ffffc900000e6bb0 EFLAGS: 00010207
> > RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
> > RDX: 0000000000000028 RSI: ffffffff849f2afb RDI: ffff888079558338
> > RBP: ffffc900000e6c48 R08: 0000000000000005 R09: 0000000000000000
> > R10: 0000000000000001 R11: 0000000000000010 R12: ffff8880795590d8
> > R13: 0000000000000144 R14: ffff8880795590d8 R15: dffffc0000000000
> > FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:00000000000=
00000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f17191c7688 CR3: 00000000281af000 CR4: 00000000003506f0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > Call Trace:
> >  <TASK>
> >  set_fence_deadline drivers/gpu/drm/drm_atomic_helper.c:1531 [inline]
> >  drm_atomic_helper_wait_for_fences+0x1b4/0x780 drivers/gpu/drm/drm_atom=
ic_helper.c:1578
> >  drm_atomic_helper_commit drivers/gpu/drm/drm_atomic_helper.c:2007 [inl=
ine]
> >  drm_atomic_helper_commit+0x1bd/0x370 drivers/gpu/drm/drm_atomic_helper=
.c:1979
> >  drm_atomic_commit+0x20a/0x300 drivers/gpu/drm/drm_atomic.c:1503
> >  drm_client_modeset_commit_atomic+0x69b/0x7e0 drivers/gpu/drm/drm_clien=
t_modeset.c:1045
> >  drm_client_modeset_commit_locked+0x149/0x580 drivers/gpu/drm/drm_clien=
t_modeset.c:1148
> >  drm_client_modeset_commit+0x51/0x80 drivers/gpu/drm/drm_client_modeset=
.c:1174
> >  drm_fb_helper_single_fb_probe drivers/gpu/drm/drm_fb_helper.c:1983 [in=
line]
> >  __drm_fb_helper_initial_config_and_unlock+0x118a/0x1510 drivers/gpu/dr=
m/drm_fb_helper.c:2169
> >  drm_fb_helper_initial_config drivers/gpu/drm/drm_fb_helper.c:2259 [inl=
ine]
> >  drm_fb_helper_initial_config+0x42/0x60 drivers/gpu/drm/drm_fb_helper.c=
:2251
> >  drm_fbdev_generic_client_hotplug+0x1ab/0x270 drivers/gpu/drm/drm_fbdev=
_generic.c:281
> >  drm_fbdev_generic_setup+0x127/0x3b0 drivers/gpu/drm/drm_fbdev_generic.=
c:343
> >  udl_usb_probe+0x120/0x190 drivers/gpu/drm/udl/udl_drv.c:120
> >  usb_probe_interface+0x30f/0x960 drivers/usb/core/driver.c:396
> >  call_driver_probe drivers/base/dd.c:579 [inline]
> >  really_probe+0x240/0xca0 drivers/base/dd.c:658
> >  __driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:795
> >  driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:825
> >  __device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:953
> >  bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:457
> >  __device_attach+0x1e4/0x4b0 drivers/base/dd.c:1025
> >  bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
> >  device_add+0x11c4/0x1c50 drivers/base/core.c:3616
> >  usb_set_configuration+0x10ee/0x1af0 drivers/usb/core/message.c:2171
> >  usb_generic_driver_probe+0xcf/0x130 drivers/usb/core/generic.c:238
> >  usb_probe_device+0xd8/0x2c0 drivers/usb/core/driver.c:293
> >  call_driver_probe drivers/base/dd.c:579 [inline]
> >  really_probe+0x240/0xca0 drivers/base/dd.c:658
> >  __driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:795
> >  driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:825
> >  __device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:953
> >  bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:457
> >  __device_attach+0x1e4/0x4b0 drivers/base/dd.c:1025
> >  bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
> >  device_add+0x11c4/0x1c50 drivers/base/core.c:3616
> >  usb_new_device+0xcb2/0x19d0 drivers/usb/core/hub.c:2575
> >  hub_port_connect drivers/usb/core/hub.c:5407 [inline]
> >  hub_port_connect_change drivers/usb/core/hub.c:5551 [inline]
> >  port_event drivers/usb/core/hub.c:5711 [inline]
> >  hub_event+0x2d9e/0x4e40 drivers/usb/core/hub.c:5793
> >  process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
> >  worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552
> >  kthread+0x33e/0x440 kernel/kthread.c:379
> >  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
> >  </TASK>
> > Modules linked in:
> > ---[ end trace 0000000000000000 ]---
> > RIP: 0010:drm_crtc_next_vblank_start+0xb3/0x2b0 drivers/gpu/drm/drm_vbl=
ank.c:1003
> > Code: e8 01 00 00 48 69 db 38 02 00 00 48 b8 00 00 00 00 00 fc ff df 49=
 03 9d 38 03 00 00 4c 8d ab 44 01 00 00 4c 89 ea 48 c1 ea 03 <0f> b6 14 02 =
4c 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 67
> > RSP: 0018:ffffc900000e6bb0 EFLAGS: 00010207
> > RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
> > RDX: 0000000000000028 RSI: ffffffff849f2afb RDI: ffff888079558338
> > RBP: ffffc900000e6c48 R08: 0000000000000005 R09: 0000000000000000
> > R10: 0000000000000001 R11: 0000000000000010 R12: ffff8880795590d8
> > R13: 0000000000000144 R14: ffff8880795590d8 R15: dffffc0000000000
> > FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:00000000000=
00000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f17191c7688 CR3: 000000002b398000 CR4: 00000000003506f0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > ----------------
> > Code disassembly (best guess):
> >    0:   e8 01 00 00 48          callq  0x48000006
> >    5:   69 db 38 02 00 00       imul   $0x238,%ebx,%ebx
> >    b:   48 b8 00 00 00 00 00    movabs $0xdffffc0000000000,%rax
> >   12:   fc ff df
> >   15:   49 03 9d 38 03 00 00    add    0x338(%r13),%rbx
> >   1c:   4c 8d ab 44 01 00 00    lea    0x144(%rbx),%r13
> >   23:   4c 89 ea                mov    %r13,%rdx
> >   26:   48 c1 ea 03             shr    $0x3,%rdx
> > * 2a:   0f b6 14 02             movzbl (%rdx,%rax,1),%edx <-- trapping =
instruction
> >   2e:   4c 89 e8                mov    %r13,%rax
> >   31:   83 e0 07                and    $0x7,%eax
> >   34:   83 c0 03                add    $0x3,%eax
> >   37:   38 d0                   cmp    %dl,%al
> >   39:   7c 08                   jl     0x43
> >   3b:   84 d2                   test   %dl,%dl
> >   3d:   0f                      .byte 0xf
> >   3e:   85                      .byte 0x85
> >   3f:   67                      addr32
> >
> >
> > ---
> > 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@googlegroups.com.
> >
> > syzbot will keep track of this issue. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > For information about bisection process see: https://goo.gl/tpsmEJ#bise=
ction
> > syzbot can test patches for this issue, for details see:
> > https://goo.gl/tpsmEJ#testing-patches
>
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