[moderation] [media?] general protection fault in subdev_open

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: bd1dde877520 Merge tag 'vfs-7.2-rc6.fixes' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17171db9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=a2c5c186a05603d90708
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
CC: [linux-...@vger.kernel.org linux...@vger.kernel.org mch...@kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-bd1dde87.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dec9ee6762c4/vmlinux-bd1dde87.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f35e776740b3/bzImage-bd1dde87.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a2c5c1...@syzkaller.appspotmail.com

netlink: 'syz.3.113': attribute type 21 has an invalid length.
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 6317 Comm: syz.3.113 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:subdev_open+0x193/0x510 drivers/media/v4l2-core/v4l2-subdev.c:115
Code: 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 bc 02 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 2c 24 48 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 04 03 00 00 48 8b 6d 00 48 85 ed 0f 84 95 00 00
RSP: 0018:ffffc900031d78a0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff8880571c0400 RCX: ffffc900078e3000
RDX: 0000000000000000 RSI: ffffffff88185523 RDI: ffff88802f1853d0
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88802f362020
R13: ffff88802f457000 R14: ffff88802c278e00 R15: ffff8880571c0538
FS: 00007fa211fb06c0(0000) GS:ffff8880d5ed8000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa211187640 CR3: 0000000059fe8000 CR4: 0000000000352ef0
Call Trace:
<TASK>
v4l2_open+0x1d2/0x490 drivers/media/v4l2-core/v4l2-dev.c:433
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6ab/0x14d0 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1052
do_open fs/namei.c:4700 [inline]
path_openat+0x2873/0x4280 fs/namei.c:4863
do_file_open+0x20e/0x430 fs/namei.c:4892
do_sys_openat2+0x10f/0x1e0 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_sys_openat fs/open.c:1390 [inline]
__se_sys_openat fs/open.c:1385 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1385
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa21115e84e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007fa211fafb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fa211fb06c0 RCX: 00007fa21115e84e
RDX: 0000000000000000 RSI: 00007fa211fafc00 RDI: ffffffffffffff9c
RBP: 00007fa211fafc00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007fa211426038 R14: 00007fa211425fa0 R15: 00007ffc70d5cd98
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:subdev_open+0x193/0x510 drivers/media/v4l2-core/v4l2-subdev.c:115
Code: 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 bc 02 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 2c 24 48 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 04 03 00 00 48 8b 6d 00 48 85 ed 0f 84 95 00 00
RSP: 0018:ffffc900031d78a0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff8880571c0400 RCX: ffffc900078e3000
RDX: 0000000000000000 RSI: ffffffff88185523 RDI: ffff88802f1853d0
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88802f362020
R13: ffff88802f457000 R14: ffff88802c278e00 R15: ffff8880571c0538
FS: 00007fa211fb06c0(0000) GS:ffff8880d5dd8000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562e687e5fe0 CR3: 0000000059fe8000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess), 7 bytes skipped:
0: 48 c1 ea 03 shr $0x3,%rdx
4: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
8: 0f 85 bc 02 00 00 jne 0x2ca
e: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
15: fc ff df
18: 49 8b 2c 24 mov (%r12),%rbp
1c: 48 89 ea mov %rbp,%rdx
1f: 48 c1 ea 03 shr $0x3,%rdx
* 23: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
27: 0f 85 04 03 00 00 jne 0x331
2d: 48 8b 6d 00 mov 0x0(%rbp),%rbp
31: 48 85 ed test %rbp,%rbp
34: 0f .byte 0xf
35: 84 .byte 0x84
36: 95 xchg %eax,%ebp


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