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: 19988 Comm: syz-executor.5 Not tainted 6.1.0-rc6-next-20221125-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 RIP: 0010:empty_backref_cache fs/btrfs/send.c:1396 [inline] RIP: 0010:btrfs_ioctl_send+0x13ab/0x65a0 fs/btrfs/send.c:8365 Code: 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 49 1c 00 00 4d 8b ae c0 01 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 34 1c 00 00 4c 39 ed 49 8b 5d 00 49 bc 00 00 00 RSP: 0018:ffffc900053af8c8 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff888075569140 RCX: ffffc9000cb7b000 RDX: 0000000000000000 RSI: ffffffff8380b588 RDI: ffff888075569000 RBP: ffff8880755691c0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffed100eaad228 R13: 0000000000000000 R14: ffff888075569000 R15: 0000000000000000 FS: 00007f69eef2d700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f69eef2d718 CR3: 0000000017942000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: _btrfs_ioctl_send+0x231/0x2e0 fs/btrfs/ioctl.c:4343 btrfs_ioctl+0xc93/0x5870 fs/btrfs/ioctl.c:4637 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f69ee28c0d9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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:00007f69eef2d168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f69ee3ac050 RCX: 00007f69ee28c0d9 RDX: 0000000020000040 RSI: 0000000040449426 RDI: 0000000000000003 RBP: 00007f69ee2e7ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdf434a35f R14: 00007f69eef2d300 R15: 0000000000022000 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:empty_backref_cache fs/btrfs/send.c:1396 [inline] RIP: 0010:btrfs_ioctl_send+0x13ab/0x65a0 fs/btrfs/send.c:8365 Code: 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 49 1c 00 00 4d 8b ae c0 01 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 34 1c 00 00 4c 39 ed 49 8b 5d 00 49 bc 00 00 00 RSP: 0018:ffffc900053af8c8 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff888075569140 RCX: ffffc9000cb7b000 RDX: 0000000000000000 RSI: ffffffff8380b588 RDI: ffff888075569000 RBP: ffff8880755691c0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffed100eaad228 R13: 0000000000000000 R14: ffff888075569000 R15: 0000000000000000 FS: 00007f69eef2d700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffefc7f6fb8 CR3: 0000000017942000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess), 4 bytes skipped: 0: 48 c1 ea 03 shr $0x3,%rdx 4: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 8: 0f 85 49 1c 00 00 jne 0x1c57 e: 4d 8b ae c0 01 00 00 mov 0x1c0(%r14),%r13 15: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1c: fc ff df 1f: 4c 89 ea mov %r13,%rdx 22: 48 c1 ea 03 shr $0x3,%rdx * 26: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction 2a: 0f 85 34 1c 00 00 jne 0x1c64 30: 4c 39 ed cmp %r13,%rbp 33: 49 8b 5d 00 mov 0x0(%r13),%rbx 37: 49 rex.WB 38: bc .byte 0xbc 39: 00 00 add %al,(%rax)