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: 3748 Comm: kworker/u16:3 Not tainted 5.16.0-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Workqueue: floppy floppy_work_workfn RIP: 0010:start_motor+0x3a/0x3f0 drivers/block/floppy.c:1906 Code: 08 e8 3a 64 fa fc 48 8b 1d d3 b2 02 0c 48 b8 00 00 00 00 00 fc ff df 0f b6 2d e2 9c 02 0c 48 89 da 48 c1 ea 03 89 e9 41 89 ed <0f> b6 04 02 83 e1 03 41 83 e5 03 84 c0 74 08 3c 03 0f 8e be 02 00 RSP: 0018:ffffc90002a1fca0 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff847c9c46 RDI: ffffffff847cd9f0 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff847cda5a R11: 0000000000000000 R12: ffffffff847cd9f0 R13: 0000000000000001 R14: ffff888011af4700 R15: ffff888010c75800 FS: 0000000000000000(0000) GS:ffff88802cb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f15fe4af378 CR3: 000000006d33d000 CR4: 0000000000150ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: floppy_ready+0x83/0x1850 drivers/block/floppy.c:1933 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307 worker_thread+0x657/0x1110 kernel/workqueue.c:2454 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Modules linked in: ---[ end trace ecef1a151be9f9c0 ]--- RIP: 0010:start_motor+0x3a/0x3f0 drivers/block/floppy.c:1906 Code: 08 e8 3a 64 fa fc 48 8b 1d d3 b2 02 0c 48 b8 00 00 00 00 00 fc ff df 0f b6 2d e2 9c 02 0c 48 89 da 48 c1 ea 03 89 e9 41 89 ed <0f> b6 04 02 83 e1 03 41 83 e5 03 84 c0 74 08 3c 03 0f 8e be 02 00 RSP: 0018:ffffc90002a1fca0 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff847c9c46 RDI: ffffffff847cd9f0 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff847cda5a R11: 0000000000000000 R12: ffffffff847cd9f0 R13: 0000000000000001 R14: ffff888011af4700 R15: ffff888010c75800 FS: 0000000000000000(0000) GS:ffff88802cb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f15fe4af378 CR3: 000000006d33d000 CR4: 0000000000150ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 08 e8 or %ch,%al 2: 3a 64 fa fc cmp -0x4(%rdx,%rdi,8),%ah 6: 48 8b 1d d3 b2 02 0c mov 0xc02b2d3(%rip),%rbx # 0xc02b2e0 d: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 14: fc ff df 17: 0f b6 2d e2 9c 02 0c movzbl 0xc029ce2(%rip),%ebp # 0xc029d00 1e: 48 89 da mov %rbx,%rdx 21: 48 c1 ea 03 shr $0x3,%rdx 25: 89 e9 mov %ebp,%ecx 27: 41 89 ed mov %ebp,%r13d * 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction 2e: 83 e1 03 and $0x3,%ecx 31: 41 83 e5 03 and $0x3,%r13d 35: 84 c0 test %al,%al 37: 74 08 je 0x41 39: 3c 03 cmp $0x3,%al 3b: 0f .byte 0xf 3c: 8e .byte 0x8e 3d: be .byte 0xbe 3e: 02 00 add (%rax),%al