syzbot
general protection fault in dummy_queue
Status:
premoderation: reported on 2026/07/25 09:31
Reported-by: syzbot+3971fdeca744f327e379@syzkaller.appspotmail.com
First crash: 56d, last: 24d
Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]
CPU: 1 PID: 1962 Comm: dhcpcd Tainted: G W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:dummy_queue+0x1b7/0x870 drivers/usb/gadget/udc/dummy_hcd.c:714
Code: fc ff df 80 3c 08 00 74 08 4c 89 e7 e8 72 53 7f fe 4d 8b 24 24 49 83 c4 48 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 80 05 00 00 45 8b 24 24 44 89 e6 83 e6 02
RSP: 0018:ffffc90000be7120 EFLAGS: 00010206
RAX: 0000000000000009 RBX: ffff888121b24210 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000005
RBP: ffffc90000be7198 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200017ce28 R12: 0000000000000048
R13: ffff888121b24200 R14: 1ffff11024364840 R15: ffff88810b6e0c90
FS: 00007ff54e7a1740(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31c23ffc CR3: 000000010e203000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
usb_ep_queue+0xce/0x210 drivers/usb/gadget/udc/core.c:288
eth_start_xmit+0x811/0xd40 drivers/usb/gadget/function/u_ether.c:589
__netdev_start_xmit include/linux/netdevice.h:5064 [inline]
netdev_start_xmit include/linux/netdevice.h:5078 [inline]
xmit_one net/core/dev.c:3670 [inline]
dev_hard_start_xmit+0x245/0x680 net/core/dev.c:3686
sch_direct_xmit+0x279/0x9c0 net/sched/sch_generic.c:345
__dev_xmit_skb net/core/dev.c:3905 [inline]
__dev_queue_xmit+0x14f1/0x2d60 net/core/dev.c:4274
dev_queue_xmit+0x17/0x20 net/core/dev.c:4355
packet_snd net/packet/af_packet.c:3094 [inline]
packet_sendmsg+0x3c54/0x5060 net/packet/af_packet.c:3125
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
sock_write_iter+0x2a6/0x3a0 net/socket.c:1080
do_iter_readv_writev+0x477/0x5f0 fs/read_write.c:-1
do_iter_write+0x207/0x7b0 fs/read_write.c:855
vfs_writev+0x2df/0x570 fs/read_write.c:928
do_writev+0x14e/0x2c0 fs/read_write.c:971
__do_sys_writev fs/read_write.c:1044 [inline]
__se_sys_writev fs/read_write.c:1041 [inline]
__x64_sys_writev+0x7d/0x90 fs/read_write.c:1041
x64_sys_call+0x974/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:21
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ff54e82b407
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:00007fff13d17e00 EFLAGS: 00000202 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007ff54e7a1740 RCX: 00007ff54e82b407
RDX: 0000000000000002 RSI: 00007fff13d17e60 RDI: 0000000000000003
RBP: 0000000000000188 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff13d17ea0
R13: 000055c0fceda0f0 R14: 00007fff13d17ef0 R15: 00007fff13d280c0
</TASK>
Modules linked in:
---[ end trace ac4fabd371f6238d ]---
RIP: 0010:dummy_queue+0x1b7/0x870 drivers/usb/gadget/udc/dummy_hcd.c:714
Code: fc ff df 80 3c 08 00 74 08 4c 89 e7 e8 72 53 7f fe 4d 8b 24 24 49 83 c4 48 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 80 05 00 00 45 8b 24 24 44 89 e6 83 e6 02
RSP: 0018:ffffc90000be7120 EFLAGS: 00010206
RAX: 0000000000000009 RBX: ffff888121b24210 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000005
RBP: ffffc90000be7198 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200017ce28 R12: 0000000000000048
R13: ffff888121b24200 R14: 1ffff11024364840 R15: ffff88810b6e0c90
FS: 00007ff54e7a1740(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31c23ffc CR3: 000000010e203000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: fc cld
1: ff lcall (bad)
2: df 80 3c 08 00 74 filds 0x7400083c(%rax)
8: 08 4c 89 e7 or %cl,-0x19(%rcx,%rcx,4)
c: e8 72 53 7f fe call 0xfe7f5383
11: 4d 8b 24 24 mov (%r12),%r12
15: 49 83 c4 48 add $0x48,%r12
19: 4c 89 e0 mov %r12,%rax
1c: 48 c1 e8 03 shr $0x3,%rax
20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx
27: fc ff df
* 2a: 0f b6 04 08 movzbl (%rax,%rcx,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 0f 85 80 05 00 00 jne 0x5b6
36: 45 8b 24 24 mov (%r12),%r12d
3a: 44 89 e6 mov %r12d,%esi
3d: 83 e6 02 and $0x2,%esi
Struck through repros no longer work on HEAD.