[syzbot] [media?] general protection fault in em28xx_resolution_set (2)

syzbot
2026-04-07T20:35:29Z

Hello,

syzbot found the following issue on:

HEAD commit: 81ebd43cc0d6 usb: gadget: f_hid: don't call cdev_init whil..
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=140d45ca580000
kernel config: https://syzkaller.appspot.com/x/.config?x=36a2baf561dcdf64
dashboard link: https://syzkaller.appspot.com/bug?extid=755151a86449f029bae0
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/59aca7fb2d65/disk-81ebd43c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/87180154ea1a/vmlinux-81ebd43c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/862a7fc58ad2/bzImage-81ebd43c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+755151a86449f029bae0@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000354: 0000 [#1] SMP KASAN PTI
KASAN: probably user-memory-access in range [0x0000000000001aa0-0x0000000000001aa7]
CPU: 0 UID: 0 PID: 5637 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:norm_maxh drivers/media/usb/em28xx/em28xx-video.c:149 [inline]
RIP: 0010:em28xx_resolution_set.isra.0+0xe4/0x730 drivers/media/usb/em28xx/em28xx-video.c:317
Code: 0f 85 d5 05 00 00 48 8d bd a0 1a 00 00 44 0f b6 bb 3c 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 41 83 e7 10 <80> 3c 02 00 0f 85 e9 05 00 00 31 ff 44 89 fe 4c 8b a5 a0 1a 00 00
RSP: 0018:ffffc90002027798 EFLAGS: 00010246

RAX: dffffc0000000000 RBX: ffff88811f368000 RCX: ffffffff85a50292
RDX: 0000000000000354 RSI: ffffffff85a4f799 RDI: 0000000000001aa0
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88812bc88000
R13: 1ffff92000404ef7 R14: ffff88811f36813c R15: 0000000000000000
FS: 00007f8c837eb880(0000) GS:ffff8882686f6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8c839e455a CR3: 000000010735c000 CR4: 00000000003506f0
Call Trace:
<TASK>
em28xx_v4l2_open+0x457/0x570 drivers/media/usb/em28xx/em28xx-video.c:2166
v4l2_open+0x1d2/0x490 drivers/media/v4l2-core/v4l2-dev.c:433
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x68b/0x14b0 fs/open.c:949
vfs_open+0x82/0x3f0 fs/open.c:1081
do_open fs/namei.c:4671 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4830
do_file_open+0x20e/0x430 fs/namei.c:4859
do_sys_openat2+0x10d/0x1e0 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0x7b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8c838d9407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffe5cd9fa90 EFLAGS: 00000202
ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f8c837eb880 RCX: 00007f8c838d9407
RDX: 0000000000000000 RSI: 00007ffe5cda0f21 RDI: ffffffffffffff9c
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffe5cd9fce0 R14: 00007f8c8406f000 R15: 0000555f3c43e4d8
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:norm_maxh drivers/media/usb/em28xx/em28xx-video.c:149 [inline]
RIP: 0010:em28xx_resolution_set.isra.0+0xe4/0x730 drivers/media/usb/em28xx/em28xx-video.c:317
Code: 0f 85 d5 05 00 00 48 8d bd a0 1a 00 00 44 0f b6 bb 3c 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 41 83 e7 10 <80> 3c 02 00 0f 85 e9 05 00 00 31 ff 44 89 fe 4c 8b a5 a0 1a 00 00
RSP: 0018:ffffc90002027798 EFLAGS: 00010246

RAX: dffffc0000000000 RBX: ffff88811f368000 RCX: ffffffff85a50292
RDX: 0000000000000354 RSI: ffffffff85a4f799 RDI: 0000000000001aa0
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000002
----------------
Code disassembly (best guess):
0: 0f 85 d5 05 00 00 jne 0x5db
6: 48 8d bd a0 1a 00 00 lea 0x1aa0(%rbp),%rdi
d: 44 0f b6 bb 3c 01 00 movzbl 0x13c(%rbx),%r15d
14: 00
15: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
1c: fc ff df
1f: 48 89 fa mov %rdi,%rdx
22: 48 c1 ea 03 shr $0x3,%rdx
26: 41 83 e7 10 and $0x10,%r15d
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 e9 05 00 00 jne 0x61d
34: 31 ff xor %edi,%edi
36: 44 89 fe mov %r15d,%esi
39: 4c 8b a5 a0 1a 00 00 mov 0x1aa0(%rbp),%r12

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