* [syzbot] [usb?] [dri?] WARNING in drm_mode_config_validate
@ 2026-08-27 18:51 syzbot
2026-08-28 6:41 ` Thomas Zimmermann
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2026-08-27 18:51 UTC (permalink / raw)
To: airlied, dri-devel, linux-kernel, linux-usb, maarten.lankhorst,
mripard, rubenru09, simona, syzkaller-bugs, tzimmermann
Hello,
syzbot found the following issue on:
HEAD commit: 45c13f3f9e3b Merge tag 'hwlock-v7.3' of git://git.kernel.o..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=10ad399e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b0fc292fc5639c
dashboard link: https://syzkaller.appspot.com/bug?extid=901485725495f4729987
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17af0579580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17639625580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ac6556827073/disk-45c13f3f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/01ff014f18d2/vmlinux-45c13f3f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/77e9c6302a14/bzImage-45c13f3f.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+901485725495f4729987@syzkaller.appspotmail.com
usb 4-1: config 1 interface 0 altsetting 0 bulk endpoint 0x1 has invalid maxpacket 0
usb 4-1: config 1 interface 0 altsetting 0 has 1 endpoint descriptor, different from the interface descriptor's value: 2
usb 4-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
------------[ cut here ]------------
[PLANE:35:plane-0] pixel format with alpha exposed but blend mode not setup
WARNING: drivers/gpu/drm/drm_mode_config.c:872 at validate_blend_mode_for_alpha_formats drivers/gpu/drm/drm_mode_config.c:872 [inline], CPU#1: kworker/1:0/24
WARNING: drivers/gpu/drm/drm_mode_config.c:872 at drm_mode_config_validate+0xfb4/0x1be0 drivers/gpu/drm/drm_mode_config.c:938, CPU#1: kworker/1:0/24
Modules linked in:
CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0 Not tainted syzkaller #0 PREEMPT(lazy)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: usb_hub_wq hub_event
RIP: 0010:validate_blend_mode_for_alpha_formats drivers/gpu/drm/drm_mode_config.c:872 [inline]
RIP: 0010:drm_mode_config_validate+0xfbb/0x1be0 drivers/gpu/drm/drm_mode_config.c:938
Code: 00 49 8b 57 18 48 89 f8 48 c1 e8 03 0f b6 04 28 84 c0 74 08 3c 03 0f 8e 00 0b 00 00 48 8d 3d fc 06 ce 07 41 8b b7 c8 00 00 00 <67> 48 0f b9 3a e9 fa fd ff ff 48 8b 5c 24 20 e8 31 3d 68 fe 48 8d
RSP: 0018:ffffc9000019edd0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff888108692dc0 RSI: 0000000000000023 RDI: ffffffff8b1a99a0
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffed102175f9ca
R13: ffffed102175f9cb R14: 0000000000000001 R15: ffff88810bafcd60
FS: 0000000000000000(0000) GS:ffff8882684eb000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000000 CR3: 0000000119ed8000 CR4: 00000000003506f0
Call Trace:
<TASK>
drm_dev_register+0x56e/0x7b0 drivers/gpu/drm/drm_drv.c:1077
gud_probe+0x17f4/0x1c20 drivers/gpu/drm/gud/gud_drv.c:646
usb_probe_interface+0x386/0x9b0 drivers/usb/core/driver.c:399
call_driver_probe drivers/base/dd.c:628 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:706
__driver_probe_device+0x210/0x460 drivers/base/dd.c:868
driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
__device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
bus_probe_device+0x64/0x160 drivers/base/bus.c:620
device_add+0x121d/0x1970 drivers/base/core.c:3776
usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268
usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:628 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:706
__driver_probe_device+0x210/0x460 drivers/base/dd.c:868
driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
__device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
bus_probe_device+0x64/0x160 drivers/base/bus.c:620
device_add+0x121d/0x1970 drivers/base/core.c:3776
usb_new_device.part.0+0xcc2/0x1686 drivers/usb/core/hub.c:2708
usb_new_device drivers/usb/core/hub.c:5833 [inline]
hub_port_connect drivers/usb/core/hub.c:5580 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
port_event drivers/usb/core/hub.c:5884 [inline]
hub_event.cold+0x51a/0xe9d drivers/usb/core/hub.c:5966
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387
process_scheduled_works kernel/workqueue.c:3470 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x69f/0xc90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
----------------
Code disassembly (best guess):
0: 00 49 8b add %cl,-0x75(%rcx)
3: 57 push %rdi
4: 18 48 89 sbb %cl,-0x77(%rax)
7: f8 clc
8: 48 c1 e8 03 shr $0x3,%rax
c: 0f b6 04 28 movzbl (%rax,%rbp,1),%eax
10: 84 c0 test %al,%al
12: 74 08 je 0x1c
14: 3c 03 cmp $0x3,%al
16: 0f 8e 00 0b 00 00 jle 0xb1c
1c: 48 8d 3d fc 06 ce 07 lea 0x7ce06fc(%rip),%rdi # 0x7ce071f
23: 41 8b b7 c8 00 00 00 mov 0xc8(%r15),%esi
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: e9 fa fd ff ff jmp 0xfffffe2e
34: 48 8b 5c 24 20 mov 0x20(%rsp),%rbx
39: e8 31 3d 68 fe call 0xfe683d6f
3e: 48 rex.W
3f: 8d .byte 0x8d
---
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.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] [usb?] [dri?] WARNING in drm_mode_config_validate
2026-08-27 18:51 [syzbot] [usb?] [dri?] WARNING in drm_mode_config_validate syzbot
@ 2026-08-28 6:41 ` Thomas Zimmermann
0 siblings, 0 replies; 2+ messages in thread
From: Thomas Zimmermann @ 2026-08-28 6:41 UTC (permalink / raw)
To: syzbot, airlied, dri-devel, linux-kernel, linux-usb,
maarten.lankhorst, mripard, rubenru09, simona, syzkaller-bugs
Hi
Am 27.08.26 um 20:51 schrieb syzbot:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 45c13f3f9e3b Merge tag 'hwlock-v7.3' of git://git.kernel.o..
> git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
> console output: https://syzkaller.appspot.com/x/log.txt?x=10ad399e580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=9b0fc292fc5639c
> dashboard link: https://syzkaller.appspot.com/bug?extid=901485725495f4729987
> compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17af0579580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17639625580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/ac6556827073/disk-45c13f3f.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/01ff014f18d2/vmlinux-45c13f3f.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/77e9c6302a14/bzImage-45c13f3f.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+901485725495f4729987@syzkaller.appspotmail.com
>
> usb 4-1: config 1 interface 0 altsetting 0 bulk endpoint 0x1 has invalid maxpacket 0
> usb 4-1: config 1 interface 0 altsetting 0 has 1 endpoint descriptor, different from the interface descriptor's value: 2
> usb 4-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
> ------------[ cut here ]------------
> [PLANE:35:plane-0] pixel format with alpha exposed but blend mode not setup
> WARNING: drivers/gpu/drm/drm_mode_config.c:872 at validate_blend_mode_for_alpha_formats drivers/gpu/drm/drm_mode_config.c:872 [inline], CPU#1: kworker/1:0/24
> WARNING: drivers/gpu/drm/drm_mode_config.c:872 at drm_mode_config_validate+0xfb4/0x1be0 drivers/gpu/drm/drm_mode_config.c:938, CPU#1: kworker/1:0/24
This comes from gud supporting ARGB8888 on it's primary plane. But the
driver does not know the hardware's blend mode without a change to the
gud protocol.
I think the easiest solution is to drop support for ARGB from gud.
Best regards
Thomas
> Modules linked in:
> CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0 Not tainted syzkaller #0 PREEMPT(lazy)
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
> Workqueue: usb_hub_wq hub_event
> RIP: 0010:validate_blend_mode_for_alpha_formats drivers/gpu/drm/drm_mode_config.c:872 [inline]
> RIP: 0010:drm_mode_config_validate+0xfbb/0x1be0 drivers/gpu/drm/drm_mode_config.c:938
> Code: 00 49 8b 57 18 48 89 f8 48 c1 e8 03 0f b6 04 28 84 c0 74 08 3c 03 0f 8e 00 0b 00 00 48 8d 3d fc 06 ce 07 41 8b b7 c8 00 00 00 <67> 48 0f b9 3a e9 fa fd ff ff 48 8b 5c 24 20 e8 31 3d 68 fe 48 8d
> RSP: 0018:ffffc9000019edd0 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
> RDX: ffff888108692dc0 RSI: 0000000000000023 RDI: ffffffff8b1a99a0
> RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000000
> R10: 0000000000000001 R11: 0000000000000000 R12: ffffed102175f9ca
> R13: ffffed102175f9cb R14: 0000000000000001 R15: ffff88810bafcd60
> FS: 0000000000000000(0000) GS:ffff8882684eb000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000200000000000 CR3: 0000000119ed8000 CR4: 00000000003506f0
> Call Trace:
> <TASK>
> drm_dev_register+0x56e/0x7b0 drivers/gpu/drm/drm_drv.c:1077
> gud_probe+0x17f4/0x1c20 drivers/gpu/drm/gud/gud_drv.c:646
> usb_probe_interface+0x386/0x9b0 drivers/usb/core/driver.c:399
> call_driver_probe drivers/base/dd.c:628 [inline]
> really_probe+0x241/0xa60 drivers/base/dd.c:706
> __driver_probe_device+0x210/0x460 drivers/base/dd.c:868
> driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
> __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
> bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
> __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
> device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
> bus_probe_device+0x64/0x160 drivers/base/bus.c:620
> device_add+0x121d/0x1970 drivers/base/core.c:3776
> usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268
> usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
> usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:293
> call_driver_probe drivers/base/dd.c:628 [inline]
> really_probe+0x241/0xa60 drivers/base/dd.c:706
> __driver_probe_device+0x210/0x460 drivers/base/dd.c:868
> driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
> __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
> bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
> __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
> device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
> bus_probe_device+0x64/0x160 drivers/base/bus.c:620
> device_add+0x121d/0x1970 drivers/base/core.c:3776
> usb_new_device.part.0+0xcc2/0x1686 drivers/usb/core/hub.c:2708
> usb_new_device drivers/usb/core/hub.c:5833 [inline]
> hub_port_connect drivers/usb/core/hub.c:5580 [inline]
> hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
> port_event drivers/usb/core/hub.c:5884 [inline]
> hub_event.cold+0x51a/0xe9d drivers/usb/core/hub.c:5966
> process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387
> process_scheduled_works kernel/workqueue.c:3470 [inline]
> worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551
> kthread+0x373/0x450 kernel/kthread.c:436
> ret_from_fork+0x69f/0xc90 arch/x86/kernel/process.c:158
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
> </TASK>
> ----------------
> Code disassembly (best guess):
> 0: 00 49 8b add %cl,-0x75(%rcx)
> 3: 57 push %rdi
> 4: 18 48 89 sbb %cl,-0x77(%rax)
> 7: f8 clc
> 8: 48 c1 e8 03 shr $0x3,%rax
> c: 0f b6 04 28 movzbl (%rax,%rbp,1),%eax
> 10: 84 c0 test %al,%al
> 12: 74 08 je 0x1c
> 14: 3c 03 cmp $0x3,%al
> 16: 0f 8e 00 0b 00 00 jle 0xb1c
> 1c: 48 8d 3d fc 06 ce 07 lea 0x7ce06fc(%rip),%rdi # 0x7ce071f
> 23: 41 8b b7 c8 00 00 00 mov 0xc8(%r15),%esi
> * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
> 2f: e9 fa fd ff ff jmp 0xfffffe2e
> 34: 48 8b 5c 24 20 mov 0x20(%rsp),%rbx
> 39: e8 31 3d 68 fe call 0xfe683d6f
> 3e: 48 rex.W
> 3f: 8d .byte 0x8d
>
>
> ---
> 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.
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, (HRB 36809, AG Nürnberg)
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-08-28 6:41 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
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2026-08-27 18:51 [syzbot] [usb?] [dri?] WARNING in drm_mode_config_validate syzbot
2026-08-28 6:41 ` Thomas Zimmermann
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