* [syzbot] [usb-storage?] divide error in alauda_transport
@ 2026-08-24 5:35 syzbot
2026-08-26 10:17 ` syzbot
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2026-08-24 5:35 UTC (permalink / raw)
To: gregkh, linux-kernel, linux-usb, stern, syzkaller-bugs,
usb-storage
Hello,
syzbot found the following issue on:
HEAD commit: 7f063b2f17ea Merge tag 'for_linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13d23e79580000
kernel config: https://syzkaller.appspot.com/x/.config?x=202110c0ee6856a6
dashboard link: https://syzkaller.appspot.com/bug?extid=dc208a8cf8d37cf3e5ac
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: i386
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16c3e549580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8ee85add2a67/disk-7f063b2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2d02bce810bb/vmlinux-7f063b2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/12151938fa51/bzImage-7f063b2f.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dc208a8cf8d37cf3e5ac@syzkaller.appspotmail.com
Oops: divide error: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 5915 Comm: usb-storage Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:alauda_read_data drivers/usb/storage/alauda.c:954 [inline]
RIP: 0010:alauda_transport+0xbd6/0x43a0 drivers/usb/storage/alauda.c:1187
Code: 24 70 e8 2d e9 2e fa 41 0f b7 c4 0f b7 cb 89 8c 24 e0 00 00 00 48 8b 5c 24 40 4c 8b 74 24 28 45 89 fc 41 89 c7 44 89 f8 31 d2 <f7> b4 24 e8 00 00 00 89 54 24 50 41 89 c5 48 89 df 89 c6 e8 52 61
RSP: 0018:ffffc9000249f860 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88807ff3ce90 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc9000249faf0 R08: ffff888026289f40 R09: 0000000000000004
R10: 00000000ffffffe0 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: ffff88807ff3d258 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125014000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f67dcda4 CR3: 0000000070670000 CR4: 00000000003526f0
Call Trace:
<TASK>
usb_stor_invoke_transport+0x115/0x1a40 drivers/usb/storage/transport.c:611
usb_stor_control_thread+0x44c/0x8f0 drivers/usb/storage/usb.c:462
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:alauda_read_data drivers/usb/storage/alauda.c:954 [inline]
RIP: 0010:alauda_transport+0xbd6/0x43a0 drivers/usb/storage/alauda.c:1187
Code: 24 70 e8 2d e9 2e fa 41 0f b7 c4 0f b7 cb 89 8c 24 e0 00 00 00 48 8b 5c 24 40 4c 8b 74 24 28 45 89 fc 41 89 c7 44 89 f8 31 d2 <f7> b4 24 e8 00 00 00 89 54 24 50 41 89 c5 48 89 df 89 c6 e8 52 61
RSP: 0018:ffffc9000249f860 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88807ff3ce90 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc9000249faf0 R08: ffff888026289f40 R09: 0000000000000004
R10: 00000000ffffffe0 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: ffff88807ff3d258 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888124f14000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1b845212c0 CR3: 0000000072220000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: 24 70 and $0x70,%al
2: e8 2d e9 2e fa call 0xfa2ee934
7: 41 0f b7 c4 movzwl %r12w,%eax
b: 0f b7 cb movzwl %bx,%ecx
e: 89 8c 24 e0 00 00 00 mov %ecx,0xe0(%rsp)
15: 48 8b 5c 24 40 mov 0x40(%rsp),%rbx
1a: 4c 8b 74 24 28 mov 0x28(%rsp),%r14
1f: 45 89 fc mov %r15d,%r12d
22: 41 89 c7 mov %eax,%r15d
25: 44 89 f8 mov %r15d,%eax
28: 31 d2 xor %edx,%edx
* 2a: f7 b4 24 e8 00 00 00 divl 0xe8(%rsp) <-- trapping instruction
31: 89 54 24 50 mov %edx,0x50(%rsp)
35: 41 89 c5 mov %eax,%r13d
38: 48 89 df mov %rbx,%rdi
3b: 89 c6 mov %eax,%esi
3d: e8 .byte 0xe8
3e: 52 push %rdx
3f: 61 (bad)
---
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:
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(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-storage?] divide error in alauda_transport
2026-08-24 5:35 [syzbot] [usb-storage?] divide error in alauda_transport syzbot
@ 2026-08-26 10:17 ` syzbot
0 siblings, 0 replies; 2+ messages in thread
From: syzbot @ 2026-08-26 10:17 UTC (permalink / raw)
To: gregkh, linux-kernel, linux-usb, stern, syzkaller-bugs,
usb-storage
syzbot has found a reproducer for the following issue on:
HEAD commit: 818bebeb63dd drm/xe: Don't hand out the flat CCS storage a..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=157ff979580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ccca94d2c01b9e78
dashboard link: https://syzkaller.appspot.com/bug?extid=dc208a8cf8d37cf3e5ac
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=113d1625580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dc208a8cf8d37cf3e5ac@syzkaller.appspotmail.com
Oops: divide error: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 6620 Comm: usb-storage 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:alauda_read_data drivers/usb/storage/alauda.c:953 [inline]
RIP: 0010:alauda_transport+0xe5a/0x35c0 drivers/usb/storage/alauda.c:1187
Code: 01 45 85 ed 0f 84 6d 1c 00 00 c7 04 24 00 00 00 00 8b 5c 24 20 e8 46 38 53 fa 31 d2 48 8b 7c 24 08 89 d8 89 5c 24 20 41 89 df <f7> 74 24 70 89 c3 89 54 24 10 89 de e8 05 c1 ff ff 44 0f b7 74 24
RSP: 0018:ffffc900044ff9d0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff87b7c98a RDI: ffff8880578f8e90
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880d5ca2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f741d1ca6e4 CR3: 0000000054fb4000 CR4: 0000000000352ef0
Call Trace:
<TASK>
usb_stor_invoke_transport+0xe7/0x15c0 drivers/usb/storage/transport.c:611
usb_stor_control_thread+0x5e4/0xae0 drivers/usb/storage/usb.c:462
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:alauda_read_data drivers/usb/storage/alauda.c:953 [inline]
RIP: 0010:alauda_transport+0xe5a/0x35c0 drivers/usb/storage/alauda.c:1187
Code: 01 45 85 ed 0f 84 6d 1c 00 00 c7 04 24 00 00 00 00 8b 5c 24 20 e8 46 38 53 fa 31 d2 48 8b 7c 24 08 89 d8 89 5c 24 20 41 89 df <f7> 74 24 70 89 c3 89 54 24 10 89 de e8 05 c1 ff ff 44 0f b7 74 24
RSP: 0018:ffffc900044ff9d0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff87b7c98a RDI: ffff8880578f8e90
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880d5ca2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f741d1ca6e4 CR3: 0000000054fb4000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
0: 01 45 85 add %eax,-0x7b(%rbp)
3: ed in (%dx),%eax
4: 0f 84 6d 1c 00 00 je 0x1c77
a: c7 04 24 00 00 00 00 movl $0x0,(%rsp)
11: 8b 5c 24 20 mov 0x20(%rsp),%ebx
15: e8 46 38 53 fa call 0xfa533860
1a: 31 d2 xor %edx,%edx
1c: 48 8b 7c 24 08 mov 0x8(%rsp),%rdi
21: 89 d8 mov %ebx,%eax
23: 89 5c 24 20 mov %ebx,0x20(%rsp)
27: 41 89 df mov %ebx,%r15d
* 2a: f7 74 24 70 divl 0x70(%rsp) <-- trapping instruction
2e: 89 c3 mov %eax,%ebx
30: 89 54 24 10 mov %edx,0x10(%rsp)
34: 89 de mov %ebx,%esi
36: e8 05 c1 ff ff call 0xffffc140
3b: 44 rex.R
3c: 0f .byte 0xf
3d: b7 74 mov $0x74,%bh
3f: 24 .byte 0x24
---
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.
^ permalink raw reply [flat|nested] 2+ messages in thread
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