[moderation] [usb?] general protection fault in adsl_state_store

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fc46aed51f62 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13e14aea580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c05be6c9b0d36cb9
dashboard link: https://syzkaller.appspot.com/bug?extid=071bdd67c08396809baf
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
CC: [3ch...@gmail.com accessrunn...@lists.sourceforge.net gre...@linuxfoundation.org linux-at...@lists.sourceforge.net linux-...@vger.kernel.org linu...@vger.kernel.org net...@vger.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-fc46aed5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b569407192b1/vmlinux-fc46aed5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/48a95132de1a/bzImage-fc46aed5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+071bdd...@syzkaller.appspotmail.com

cxacru 5-1:1.0: receive of cm 0x85 failed (-104)
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 0 UID: 0 PID: 5331 Comm: syz.0.0 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:adsl_state_store+0x5cc/0x770 drivers/usb/atm/cxacru.c:359
Code: 03 42 80 3c 28 00 74 14 48 89 4c 24 10 48 8b 7c 24 10 e8 e7 2a 88 fa 48 8b 4c 24 10 48 8b 11 48 83 c2 10 48 89 d0 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 4b 01 00 00 4d 89 f4 8b 32 48 c7 c7 e0
RSP: 0018:ffffc9000e4e7b80 EFLAGS: 00010202
RAX: 0000000000000002 RBX: 00000000ffffff98 RCX: ffff888012a8a078
RDX: 0000000000000010 RSI: 0000000000000921 RDI: 0000000000000922
RBP: ffffc9000e4e7c40 R08: ffffc9000e4e7907 R09: 1ffff92001c9cf20
R10: dffffc0000000000 R11: fffff52001c9cf21 R12: ffff888012a94800
R13: dffffc0000000000 R14: 0000000000000004 R15: 1ffff92001c9cf74
FS: 00007fc1b27276c0(0000) GS:ffff88808c543000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557fe57a58 CR3: 0000000040ae6000 CR4: 0000000000352ef0
Call Trace:
<TASK>
kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x612/0xba0 fs/read_write.c:687
ksys_write+0x150/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc1b179df99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc1b2726fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc1b1a26090 RCX: 00007fc1b179df99
RDX: 0000000000000005 RSI: 0000200000001200 RDI: 0000000000000004
RBP: 00007fc1b1834ec4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc1b1a26128 R14: 00007fc1b1a26090 R15: 00007fff838eac28
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:adsl_state_store+0x5cc/0x770 drivers/usb/atm/cxacru.c:359
Code: 03 42 80 3c 28 00 74 14 48 89 4c 24 10 48 8b 7c 24 10 e8 e7 2a 88 fa 48 8b 4c 24 10 48 8b 11 48 83 c2 10 48 89 d0 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 4b 01 00 00 4d 89 f4 8b 32 48 c7 c7 e0
RSP: 0018:ffffc9000e4e7b80 EFLAGS: 00010202
RAX: 0000000000000002 RBX: 00000000ffffff98 RCX: ffff888012a8a078
RDX: 0000000000000010 RSI: 0000000000000921 RDI: 0000000000000922
RBP: ffffc9000e4e7c40 R08: ffffc9000e4e7907 R09: 1ffff92001c9cf20
R10: dffffc0000000000 R11: fffff52001c9cf21 R12: ffff888012a94800
R13: dffffc0000000000 R14: 0000000000000004 R15: 1ffff92001c9cf74
FS: 00007fc1b27276c0(0000) GS:ffff88808c543000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557fe57a58 CR3: 0000000040ae6000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
0: 03 42 80 add -0x80(%rdx),%eax
3: 3c 28 cmp $0x28,%al
5: 00 74 14 48 add %dh,0x48(%rsp,%rdx,1)
9: 89 4c 24 10 mov %ecx,0x10(%rsp)
d: 48 8b 7c 24 10 mov 0x10(%rsp),%rdi
12: e8 e7 2a 88 fa call 0xfa882afe
17: 48 8b 4c 24 10 mov 0x10(%rsp),%rcx
1c: 48 8b 11 mov (%rcx),%rdx
1f: 48 83 c2 10 add $0x10,%rdx
23: 48 89 d0 mov %rdx,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax <-- trapping instruction
2f: 84 c0 test %al,%al
31: 0f 85 4b 01 00 00 jne 0x182
37: 4d 89 f4 mov %r14,%r12
3a: 8b 32 mov (%rdx),%esi
3c: 48 rex.W
3d: c7 .byte 0xc7
3e: c7 (bad)
3f: e0 .byte 0xe0


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