syz.4.2159: attempt to access beyond end of device loop4: rw=0, sector=167, nr_sectors = 1 limit=0 Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] CPU: 0 UID: 0 PID: 17262 Comm: syz.4.2159 Not tainted 6.12.0-next-20241125-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:exfat_find_empty_entry+0x16c9/0x1a10 fs/exfat/namei.c:398 Code: 3a 89 ff 48 8b 1b 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 75 3a 89 ff 48 8b 1b 48 83 c3 18 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 58 3a 89 ff 4c 8b 33 48 8b 54 24 RSP: 0018:ffffc9000d5d7120 EFLAGS: 00010206 RAX: 0000000000000003 RBX: 0000000000000018 RCX: 0000000000080000 RDX: ffffc9001491e000 RSI: 00000000000078a0 RDI: 00000000000078a1 RBP: ffffc9000d5d7370 R08: ffffffff828123e8 R09: 1ffff1100f959e80 R10: dffffc0000000000 R11: ffffed100f959e81 R12: 00000000fffffffb R13: ffffc9000d5d7820 R14: ffff88805aa6cee8 R15: dffffc0000000000 FS: 00007f9a7cd566c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555585764808 CR3: 000000005d944000 CR4: 00000000003526f0 Call Trace: exfat_add_entry+0x409/0xaa0 fs/exfat/namei.c:496 exfat_create+0x1c7/0x570 fs/exfat/namei.c:565 lookup_open fs/namei.c:3649 [inline] open_last_lookups fs/namei.c:3748 [inline] path_openat+0x1c03/0x3590 fs/namei.c:3984 do_filp_open+0x27f/0x4e0 fs/namei.c:4014 do_sys_openat2+0x13e/0x1d0 fs/open.c:1402 do_sys_open fs/open.c:1417 [inline] __do_sys_open fs/open.c:1425 [inline] __se_sys_open fs/open.c:1421 [inline] __x64_sys_open+0x225/0x270 fs/open.c:1421 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9a7bf7e819 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9a7cd56038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007f9a7c135fa0 RCX: 00007f9a7bf7e819 RDX: 0000000000000000 RSI: 0000000000101bff RDI: 0000000020000100 RBP: 00007f9a7bff175e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f9a7c135fa0 R15: 00007ffcabb81658 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:exfat_find_empty_entry+0x16c9/0x1a10 fs/exfat/namei.c:398 Code: 3a 89 ff 48 8b 1b 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 75 3a 89 ff 48 8b 1b 48 83 c3 18 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 58 3a 89 ff 4c 8b 33 48 8b 54 24 RSP: 0018:ffffc9000d5d7120 EFLAGS: 00010206 RAX: 0000000000000003 RBX: 0000000000000018 RCX: 0000000000080000 RDX: ffffc9001491e000 RSI: 00000000000078a0 RDI: 00000000000078a1 RBP: ffffc9000d5d7370 R08: ffffffff828123e8 R09: 1ffff1100f959e80 R10: dffffc0000000000 R11: ffffed100f959e81 R12: 00000000fffffffb R13: ffffc9000d5d7820 R14: ffff88805aa6cee8 R15: dffffc0000000000 FS: 00007f9a7cd566c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000560a6a20d950 CR3: 000000005d944000 CR4: 00000000003526f0 ---------------- Code disassembly (best guess): 0: 3a 89 ff 48 8b 1b cmp 0x1b8b48ff(%rcx),%cl 6: 48 89 d8 mov %rbx,%rax 9: 48 c1 e8 03 shr $0x3,%rax d: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) 12: 74 08 je 0x1c 14: 48 89 df mov %rbx,%rdi 17: e8 75 3a 89 ff call 0xff893a91 1c: 48 8b 1b mov (%rbx),%rbx 1f: 48 83 c3 18 add $0x18,%rbx 23: 48 89 d8 mov %rbx,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) <-- trapping instruction 2f: 74 08 je 0x39 31: 48 89 df mov %rbx,%rdi 34: e8 58 3a 89 ff call 0xff893a91 39: 4c 8b 33 mov (%rbx),%r14 3c: 48 rex.W 3d: 8b .byte 0x8b 3e: 54 push %rsp 3f: 24 .byte 0x24