RAX: ffffffffffffffda RBX: 00007f13f9114f60 RCX: 00007f13f90020e9 RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000004 RBP: 00007f13f905c08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffeaa5c990f R14: 00007f13f8f78300 R15: 0000000000022000 ---[ end trace 6c6362f4614ace13 ]--- general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 PID: 415 Comm: syz-executor.0 Tainted: G W 5.10.117-syzkaller-986967-g0974b8411a58-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:strchr+0x23/0xa0 lib/string.c:435 Code: 41 5f 5d c3 0f 1f 00 55 48 89 e5 41 57 41 56 41 54 53 49 89 fe 49 bf 00 00 00 00 00 fc ff df 44 0f be e6 48 89 f8 48 c1 e8 03 <42> 8a 04 38 84 c0 75 5d 41 0f be 06 41 39 c4 74 48 49 8d 5e 01 0f RSP: 0018:ffffc90000f079a0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88810c9a13c0 RDX: 0000000000000000 RSI: 0000000000000021 RDI: 0000000000000000 RBP: ffffc90000f079c0 R08: ffffc90000f07a60 R09: ffffc90000f07a80 R10: fffff520001e0f5a R11: 1ffff920001e0f50 R12: 0000000000000021 R13: ffff88810d687068 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f13f8f78700(0000) GS:ffff8881f7200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f13f8f56ff8 CR3: 000000010b2af000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: device_get_devnode+0x23f/0x2b0 drivers/base/core.c:3528 devtmpfs_delete_node+0xdd/0x2e0 drivers/base/devtmpfs.c:152 device_del+0x351/0xf90 drivers/base/core.c:3409 del_gendisk+0xbf2/0xe20 block/genhd.c:953 loop_remove+0x46/0xb0 drivers/block/loop.c:2185 loop_control_ioctl+0x67f/0x740 drivers/block/loop.c:2284 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0x115/0x190 fs/ioctl.c:739 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f13f90020e9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f13f8f78168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f13f9114f60 RCX: 00007f13f90020e9 RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000004 RBP: 00007f13f905c08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffeaa5c990f R14: 00007f13f8f78300 R15: 0000000000022000 Modules linked in: ---[ end trace 6c6362f4614ace14 ]--- RIP: 0010:strchr+0x23/0xa0 lib/string.c:435 Code: 41 5f 5d c3 0f 1f 00 55 48 89 e5 41 57 41 56 41 54 53 49 89 fe 49 bf 00 00 00 00 00 fc ff df 44 0f be e6 48 89 f8 48 c1 e8 03 <42> 8a 04 38 84 c0 75 5d 41 0f be 06 41 39 c4 74 48 49 8d 5e 01 0f RSP: 0018:ffffc90000f079a0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88810c9a13c0 RDX: 0000000000000000 RSI: 0000000000000021 RDI: 0000000000000000 RBP: ffffc90000f079c0 R08: ffffc90000f07a60 R09: ffffc90000f07a80 R10: fffff520001e0f5a R11: 1ffff920001e0f50 R12: 0000000000000021 R13: ffff88810d687068 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f13f8f78700(0000) GS:ffff8881f7200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f13f8f56ff8 CR3: 000000010b2af000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 41 5f pop %r15 2: 5d pop %rbp 3: c3 retq 4: 0f 1f 00 nopl (%rax) 7: 55 push %rbp 8: 48 89 e5 mov %rsp,%rbp b: 41 57 push %r15 d: 41 56 push %r14 f: 41 54 push %r12 11: 53 push %rbx 12: 49 89 fe mov %rdi,%r14 15: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15 1c: fc ff df 1f: 44 0f be e6 movsbl %sil,%r12d 23: 48 89 f8 mov %rdi,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 8a 04 38 mov (%rax,%r15,1),%al <-- trapping instruction 2e: 84 c0 test %al,%al 30: 75 5d jne 0x8f 32: 41 0f be 06 movsbl (%r14),%eax 36: 41 39 c4 cmp %eax,%r12d 39: 74 48 je 0x83 3b: 49 8d 5e 01 lea 0x1(%r14),%rbx 3f: 0f .byte 0xf