syzbot
general protection fault in dummy_set_selfpowered
Status:
upstream: reported C repro on 2026/07/26 13:33
Reported-by: syzbot+2b15f56c84869c71aba2@syzkaller.appspotmail.com
First crash: 3d10h, last: 9h22m
Sample crash report:
dummy_hcd dummy_hcd.0: remove, state 4
usb usb1: USB disconnect, device number 1
dummy_hcd dummy_hcd.0: stopped
dummy_hcd dummy_hcd.0: USB bus 1 deregistered
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 376 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:dummy_set_selfpowered+0xbc/0x150 drivers/usb/gadget/udc/dummy_hcd.c:887
Code: 94 c0 4d 8d b4 c6 e0 04 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 5e 8f 6a fe 4d 8b 3e 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 45 8f 6a fe 41 be 68 11 00 00 4d
RSP: 0018:ffffc90000787738 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff888114b3d100 RSI: 0000000000000003 RDI: 0000000000000005
RBP: ffffc90000787758 R08: ffff8881001b0267 R09: 1ffff1102003604c
R10: 0000000000000000 R11: ffffed102003604d R12: dffffc0000000000
R13: ffff888115be0468 R14: ffff88810da4d170 R15: 0000000000000000
FS: 000055557fb0a500(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffec54f2e88 CR3: 000000012c13f000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
usb_gadget_set_selfpowered+0x7a/0x190 drivers/usb/gadget/udc/core.c:554
composite_dev_prepare+0x2e7/0x310 drivers/usb/gadget/composite.c:2279
configfs_composite_bind+0xb4/0x13b0 drivers/usb/gadget/configfs.c:1339
gadget_bind_driver+0x2eb/0x990 drivers/usb/gadget/udc/core.c:1623
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2d7/0x9a0 drivers/base/dd.c:639
__driver_probe_device+0x193/0x270 drivers/base/dd.c:808
driver_probe_device+0x54/0x3e0 drivers/base/dd.c:838
__driver_attach+0x41a/0x5d0 drivers/base/dd.c:1224
bus_for_each_dev+0x18c/0x200 drivers/base/bus.c:303
driver_attach+0x42/0x50 drivers/base/dd.c:1241
bus_add_driver+0x322/0x560 drivers/base/bus.c:620
driver_register+0x335/0x440 drivers/base/driver.c:246
usb_gadget_register_driver_owner+0xf8/0x270 drivers/usb/gadget/udc/core.c:1713
gadget_dev_desc_UDC_store+0x220/0x340 drivers/usb/gadget/configfs.c:327
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x323/0x410 fs/configfs/file.c:229
call_write_iter include/linux/fs.h:2282 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x5ef/0xd00 fs/read_write.c:584
ksys_write+0x14a/0x260 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__x64_sys_write+0x7b/0x90 fs/read_write.c:646
x64_sys_call+0x27b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6794f9de99
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:00007ffe350dffb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f6795225fa0 RCX: 00007f6794f9de99
RDX: 000000000000000c RSI: 0000200000000600 RDI: 0000000000000004
RBP: 00007f6795033eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6795225fac R14: 00007f6795225fa0 R15: 00007f6795225fa0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dummy_set_selfpowered+0xbc/0x150 drivers/usb/gadget/udc/dummy_hcd.c:887
Code: 94 c0 4d 8d b4 c6 e0 04 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 5e 8f 6a fe 4d 8b 3e 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 45 8f 6a fe 41 be 68 11 00 00 4d
RSP: 0018:ffffc90000787738 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff888114b3d100 RSI: 0000000000000003 RDI: 0000000000000005
RBP: ffffc90000787758 R08: ffff8881001b0267 R09: 1ffff1102003604c
R10: 0000000000000000 R11: ffffed102003604d R12: dffffc0000000000
R13: ffff888115be0468 R14: ffff88810da4d170 R15: 0000000000000000
FS: 000055557fb0a500(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556ec2343b90 CR3: 000000012c13f000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 2 bytes skipped:
0: 4d 8d b4 c6 e0 04 00 lea 0x4e0(%r14,%rax,8),%r14
7: 00
8: 4c 89 f0 mov %r14,%rax
b: 48 c1 e8 03 shr $0x3,%rax
f: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1)
14: 74 08 je 0x1e
16: 4c 89 f7 mov %r14,%rdi
19: e8 5e 8f 6a fe call 0xfe6a8f7c
1e: 4d 8b 3e mov (%r14),%r15
21: 4c 89 f8 mov %r15,%rax
24: 48 c1 e8 03 shr $0x3,%rax
* 28: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction
2d: 74 08 je 0x37
2f: 4c 89 ff mov %r15,%rdi
32: e8 45 8f 6a fe call 0xfe6a8f7c
37: 41 be 68 11 00 00 mov $0x1168,%r14d
3d: 4d rex.WRB
Struck through repros no longer work on HEAD.