syzbot
general protection fault in bus_remove_device
Status:
upstream: reported C repro on 2026/09/21 21:51
Reported-by: syzbot+df79922b6de934babba8@syzkaller.appspotmail.com
First crash: 1d08h, last: 1d08h
Sample crash report:
usb 1-1: 1:1 : UAC_AS_GENERAL descriptor not found
usb 1-1: selecting invalid altsetting 0
usb 1-1: USB disconnect, device number 2
general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]
CPU: 1 PID: 40 Comm: kworker/1:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: usb_hub_wq hub_event
RIP: 0010:klist_put lib/klist.c:212 [inline]
RIP: 0010:klist_del lib/klist.c:230 [inline]
RIP: 0010:klist_remove+0x150/0x300 lib/klist.c:249
Code: 13 00 49 89 df 49 c1 ef 03 43 80 3c 27 00 74 08 48 89 df e8 82 d1 c8 fc 4c 8b 33 49 83 e6 fe 49 8d 7e 20 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 05 e8 64 d1 c8 fc 49 8b 46 20 48 89 44 24 18 4c
RSP: 0018:ffffc9000029f6a0 EFLAGS: 00010202
RAX: 0000000000000004 RBX: ffff888110612c48 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff878da5a0 RDI: 0000000000000020
RBP: ffffc9000029f798 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000053ec4 R12: dffffc0000000000
R13: 1ffff92000053ed8 R14: 0000000000000000 R15: 1ffff110220c2589
FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fef88bb117c CR3: 000000010efa8000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__device_release_driver drivers/base/dd.c:1291 [inline]
device_release_driver_internal+0x6a3/0x7e0 drivers/base/dd.c:1309
device_release_driver+0x19/0x20 drivers/base/dd.c:1332
bus_remove_device+0x2f0/0x350 drivers/base/bus.c:531
device_del+0x63c/0xe50 drivers/base/core.c:3886
usb_disable_device+0x3a8/0x750 drivers/usb/core/message.c:1472
usb_disconnect+0x32d/0x880 drivers/usb/core/hub.c:2339
hub_port_connect drivers/usb/core/hub.c:5433 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5734 [inline]
port_event drivers/usb/core/hub.c:5898 [inline]
hub_event+0x1a66/0x4310 drivers/usb/core/hub.c:5980
process_one_work+0x717/0xc30 kernel/workqueue.c:2302
process_scheduled_works kernel/workqueue.c:2365 [inline]
worker_thread+0xcc2/0x11d0 kernel/workqueue.c:2451
kthread+0x281/0x320 kernel/kthread.c:386
----------------
Code disassembly (best guess):
0: 13 00 adc (%rax),%eax
2: 49 89 df mov %rbx,%r15
5: 49 c1 ef 03 shr $0x3,%r15
9: 43 80 3c 27 00 cmpb $0x0,(%r15,%r12,1)
e: 74 08 je 0x18
10: 48 89 df mov %rbx,%rdi
13: e8 82 d1 c8 fc call 0xfcc8d19a
18: 4c 8b 33 mov (%rbx),%r14
1b: 49 83 e6 fe and $0xfffffffffffffffe,%r14
1f: 49 8d 7e 20 lea 0x20(%r14),%rdi
23: 48 89 f8 mov %rdi,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction
2f: 74 05 je 0x36
31: e8 64 d1 c8 fc call 0xfcc8d19a
36: 49 8b 46 20 mov 0x20(%r14),%rax
3a: 48 89 44 24 18 mov %rax,0x18(%rsp)
3f: 4c rex.WR
* Struck through repros no longer work on HEAD.