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 Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 UID: 0 PID: 1844 Comm: syz.0.489 Not tainted syzkaller #0 0b31bef96cff8e44f9e14c4f768eb06c85e3b290 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:set_link_state+0x2a/0x1240 drivers/usb/gadget/udc/dummy_hcd.c:435 Code: 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 60 49 89 fd 48 bb 00 00 00 00 00 fc ff df e8 dd 01 ce fd 4c 89 e8 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 ef e8 b8 c4 26 fe 4d 8b 75 00 49 8d 95 93 RSP: 0018:ffffc9000f3b7758 EFLAGS: 00010046 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000080000 RDX: ffffc90001641000 RSI: 0000000000000efd RDI: 0000000000000efe RBP: ffffc9000f3b77e0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52001e76ee8 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ffff888104b9c000 FS: 00007f492bda36c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd3d139db8 CR3: 0000000135208000 CR4: 00000000003526b0 DR0: 0000000000000004 DR1: 0000000000000002 DR2: 0000000000000006 DR3: 0000000000009a47 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: dummy_pullup+0xd1/0x130 drivers/usb/gadget/udc/dummy_hcd.c:914 usb_gadget_disconnect_locked+0x151/0x400 drivers/usb/gadget/udc/core.c:780 gadget_unbind_driver+0xaf/0x3f0 drivers/usb/gadget/udc/core.c:1670 device_remove drivers/base/dd.c:567 [inline] __device_release_driver drivers/base/dd.c:1272 [inline] device_release_driver_internal+0x4ad/0x830 drivers/base/dd.c:1295 device_release_driver+0x1d/0x30 drivers/base/dd.c:1318 bus_remove_device+0x34f/0x370 drivers/base/bus.c:576 device_del+0x583/0xcf0 drivers/base/core.c:3881 usb_del_gadget+0x18f/0x200 drivers/usb/gadget/udc/core.c:1550 usb_del_gadget_udc+0x19/0x30 drivers/usb/gadget/udc/core.c:1566 dummy_udc_remove+0x5c/0x70 drivers/usb/gadget/udc/dummy_hcd.c:1123 platform_remove+0x7e/0xb0 drivers/base/platform.c:1424 device_remove drivers/base/dd.c:567 [inline] __device_release_driver drivers/base/dd.c:1272 [inline] device_release_driver_internal+0x4ad/0x830 drivers/base/dd.c:1295 device_driver_detach+0x3f/0x50 drivers/base/dd.c:1331 unbind_store+0x1ab/0x1f0 drivers/base/bus.c:244 drv_attr_store+0x91/0xb0 drivers/base/bus.c:125 sysfs_kf_write+0x141/0x160 fs/sysfs/file.c:136 kernfs_fop_write_iter+0x319/0x510 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:591 [inline] vfs_write+0x762/0xfd0 fs/read_write.c:684 ksys_write+0x145/0x260 fs/read_write.c:737 __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x7f/0x90 fs/read_write.c:746 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/common.c:47 [inline] do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f492af9df99 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:00007f492bda3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f492b225fa0 RCX: 00007f492af9df99 RDX: 000000000000000b RSI: 0000200000000a00 RDI: 0000000000000007 RBP: 00007f492b034ec4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f492b226038 R14: 00007f492b225fa0 R15: 00007ffd8ffa5a28 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:set_link_state+0x2a/0x1240 drivers/usb/gadget/udc/dummy_hcd.c:435 Code: 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 60 49 89 fd 48 bb 00 00 00 00 00 fc ff df e8 dd 01 ce fd 4c 89 e8 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 ef e8 b8 c4 26 fe 4d 8b 75 00 49 8d 95 93 RSP: 0018:ffffc9000f3b7758 EFLAGS: 00010046 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000080000 RDX: ffffc90001641000 RSI: 0000000000000efd RDI: 0000000000000efe RBP: ffffc9000f3b77e0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52001e76ee8 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ffff888104b9c000 FS: 00007f492bda36c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd3d139db8 CR3: 0000000135208000 CR4: 00000000003526b0 DR0: 0000000000000004 DR1: 0000000000000002 DR2: 0000000000000006 DR3: 0000000000009a47 DR6: 00000000ffff0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 55 push %rbp 1: 48 89 e5 mov %rsp,%rbp 4: 41 57 push %r15 6: 41 56 push %r14 8: 41 55 push %r13 a: 41 54 push %r12 c: 53 push %rbx d: 48 83 ec 60 sub $0x60,%rsp 11: 49 89 fd mov %rdi,%r13 14: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx 1b: fc ff df 1e: e8 dd 01 ce fd call 0xfdce0200 23: 4c 89 e8 mov %r13,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 4c 89 ef mov %r13,%rdi 33: e8 b8 c4 26 fe call 0xfe26c4f0 38: 4d 8b 75 00 mov 0x0(%r13),%r14 3c: 49 rex.WB 3d: 8d .byte 0x8d 3e: 95 xchg %eax,%ebp 3f: 93 xchg %eax,%ebx