syzbot


general protection fault in exfat_find_empty_entry

Status: upstream: reported C repro on 2024/12/21 02:14
Subsystems: exfat
[Documentation on labels]
Reported-by: syzbot+8941485e471cec199c9e@syzkaller.appspotmail.com
First crash: 25d, last: 11h41m
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [exfat?] general protection fault in exfat_find_empty_entry 0 (1) 2024/12/21 02:14

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 UID: 0 PID: 5363 Comm: syz-executor144 Not tainted 6.13.0-rc3-syzkaller-00193-ge9b8ffafd20a #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:exfat_find_empty_entry+0x16c9/0x1a10 fs/exfat/namei.c:398
Code: 46 8b ff 48 8b 1b 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 f5 45 8b 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 d8 45 8b ff 4c 8b 33 48 8b 54 24
RSP: 0018:ffffc9000d2af120 EFLAGS: 00010206
RAX: 0000000000000003 RBX: 0000000000000018 RCX: ffff88800068c880
RDX: 0000000000000000 RSI: 00000000fffffffb RDI: 00000000fffffffb
RBP: ffffc9000d2af370 R08: ffffffff827a8268 R09: 1ffff110089f4c63
R10: dffffc0000000000 R11: ffffed10089f4c64 R12: 00000000fffffffb
R13: ffffc9000d2af820 R14: ffff888044f981a8 R15: dffffc0000000000
FS:  00007f746cfe96c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f746cfe9d58 CR3: 000000004287a000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 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_openat fs/open.c:1433 [inline]
 __se_sys_openat fs/open.c:1428 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1428
 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: 0033:0x7f746d074ed9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 18 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f746cfe9218 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f746d0fe6e8 RCX: 00007f746d074ed9
RDX: 000000000000275a RSI: 0000000020000000 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 00007fff65f63967 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f746d0fe6e0
R13: 00007f746d0cab00 R14: 0030656c69662f2e R15: 00303636396f7369
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:exfat_find_empty_entry+0x16c9/0x1a10 fs/exfat/namei.c:398
Code: 46 8b ff 48 8b 1b 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 f5 45 8b 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 d8 45 8b ff 4c 8b 33 48 8b 54 24
RSP: 0018:ffffc9000d2af120 EFLAGS: 00010206
RAX: 0000000000000003 RBX: 0000000000000018 RCX: ffff88800068c880
RDX: 0000000000000000 RSI: 00000000fffffffb RDI: 00000000fffffffb
RBP: ffffc9000d2af370 R08: ffffffff827a8268 R09: 1ffff110089f4c63
R10: dffffc0000000000 R11: ffffed10089f4c64 R12: 00000000fffffffb
R13: ffffc9000d2af820 R14: ffff888044f981a8 R15: dffffc0000000000
FS:  00007f746cfe96c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7464a14000 CR3: 000000004287a000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	46 8b ff             	rex.RX mov %edi,%r15d
   3:	48 8b 1b             	mov    (%rbx),%rbx
   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 f5 45 8b ff       	call   0xff8b4611
  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 d8 45 8b ff       	call   0xff8b4611
  39:	4c 8b 33             	mov    (%rbx),%r14
  3c:	48                   	rex.W
  3d:	8b                   	.byte 0x8b
  3e:	54                   	push   %rsp
  3f:	24                   	.byte 0x24

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/21 02:13 upstream e9b8ffafd20a d7f584ee .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci-snapshot-upstream-root general protection fault in exfat_find_empty_entry
2024/12/21 01:32 upstream e9b8ffafd20a d7f584ee .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in exfat_find_empty_entry
2024/12/15 21:50 upstream dccbe2047a5b 7cbfbb3a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in exfat_find_empty_entry
2024/12/03 05:10 upstream cdd30ebb1b9f bb326ffb .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in exfat_find_empty_entry
2024/11/25 18:25 linux-next 85a2dd7d7c81 a84878fc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in exfat_find_empty_entry
* Struck through repros no longer work on HEAD.