[syzbot] [dri?] general protection fault in drm_crtc_next_vblank_start

[syzbot]

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=1001d1cdc80000
kernel config: https://syzkaller.appspot.com/x/.config?x=aceb117f7924508e
dashboard link: https://syzkaller.appspot.com/bug?extid=54280c5aea19802490b5
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13435a2ec80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=139c9c21c80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ec1f900ea929/disk-a6d9e303.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fabbf89c0d22/vmlinux-a6d9e303.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1ed05d6192fa/bzImage-a6d9e303.xz

The issue was bisected to:

commit d39e48ca80c0960b039cb38633957f0040f63e1a
Author: Rob Clark <robd...@chromium.org>
Date: Fri Sep 3 18:47:54 2021 +0000

drm/atomic-helper: Set fence deadline for vblank

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12d260c9c80000
final oops: https://syzkaller.appspot.com/x/report.txt?x=11d260c9c80000
console output: https://syzkaller.appspot.com/x/log.txt?x=16d260c9c80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+54280c...@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 0xdffffc0000000028: 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-syzkaller #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_vblank.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:0000000000000000
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_atomic_helper.c:1578
drm_atomic_helper_commit drivers/gpu/drm/drm_atomic_helper.c:2007 [inline]
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_client_modeset.c:1045
drm_client_modeset_commit_locked+0x149/0x580 drivers/gpu/drm/drm_client_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 [inline]
__drm_fb_helper_initial_config_and_unlock+0x118a/0x1510 drivers/gpu/drm/drm_fb_helper.c:2169
drm_fb_helper_initial_config drivers/gpu/drm/drm_fb_helper.c:2259 [inline]
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_vblank.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:0000000000000000
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


---
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Rob Clark]

On Mon, Apr 3, 2023 at 12:57 AM syzbot
<syzbot+54280c...@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=1001d1cdc80000
> kernel config: https://syzkaller.appspot.com/x/.config?x=aceb117f7924508e
> dashboard link: https://syzkaller.appspot.com/bug?extid=54280c5aea19802490b5
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13435a2ec80000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=139c9c21c80000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/ec1f900ea929/disk-a6d9e303.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/fabbf89c0d22/vmlinux-a6d9e303.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/1ed05d6192fa/bzImage-a6d9e303.xz
>
> The issue was bisected to:
>
> commit d39e48ca80c0960b039cb38633957f0040f63e1a
> Author: Rob Clark <robd...@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/

BR,
-R

[Dmitry Vyukov]

On Mon, 3 Apr 2023 at 18:26, Rob Clark <robd...@chromium.org> wrote:
>
> On Mon, Apr 3, 2023 at 12:57 AM syzbot
> <syzbot+54280c...@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=1001d1cdc80000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=aceb117f7924508e
> > dashboard link: https://syzkaller.appspot.com/bug?extid=54280c5aea19802490b5
> > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13435a2ec80000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=139c9c21c80000
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/ec1f900ea929/disk-a6d9e303.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/fabbf89c0d22/vmlinux-a6d9e303.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/1ed05d6192fa/bzImage-a6d9e303.xz
> >
> > The issue was bisected to:
> >
> > commit d39e48ca80c0960b039cb38633957f0040f63e1a
> > Author: Rob Clark <robd...@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 future:

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

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