syzbot


general protection fault in hfs_find_init

Status: upstream: reported C repro on 2025/08/01 18:56
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+93a71d3cfb4c83a1d545@syzkaller.appspotmail.com
First crash: 25d, last: 20d
Bug presence (2)
Date Name Commit Repro Result
2025/08/05 linux-6.6.y (ToT) 3a8ababb8b6a C [report] general protection fault in hfs_find_init
2025/08/05 upstream (ToT) 7e161a991ea7 C Didn't crash
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 general protection fault in hfs_find_init hfs 2 C 3 907d 997d 0/1 upstream: reported C repro on 2022/12/03 11:10
linux-5.15 BUG: unable to handle kernel paging request in hfs_find_init origin:upstream 8 C error 39 8d18h 874d 0/3 upstream: reported C repro on 2023/04/05 08:29
upstream general protection fault in hfs_find_init hfs 10 C done 1024 25d 2705d 0/29 upstream: reported C repro on 2018/03/31 20:47
linux-4.19 general protection fault in hfs_find_init hfs 2 C 12 908d 1003d 0/1 upstream: reported C repro on 2022/11/26 21:41
linux-6.1 BUG: unable to handle kernel paging request in hfs_find_init origin:upstream 8 C error 37 13d 897d 0/3 upstream: reported C repro on 2023/03/13 10:13

Sample crash report:
syz.0.17[5946]: memfd_create() called without MFD_EXEC or MFD_NOEXEC_SEAL set
loop0: detected capacity change from 0 to 64
general protection fault, probably for non-canonical address 0xdffffc0000000008: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047]
CPU: 1 PID: 5946 Comm: syz.0.17 Not tainted 6.6.101-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:hfs_find_init+0x6a/0x1d0 fs/hfs/bfind.c:21
Code: 7e 18 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 c8 7c 87 ff 49 c7 07 00 00 00 00 48 8d 6b 40 49 89 ef 49 c1 ef 03 <43> 0f b6 04 2f 84 c0 0f 85 01 01 00 00 8b 45 00 8d 7c 00 04 be c0
RSP: 0018:ffffc900032d7388 EFLAGS: 00010202
RAX: 1ffff9200065ae8f RBX: 0000000000000000 RCX: ffff888026720000
RDX: 0000000000000000 RSI: ffffc900032d7460 RDI: ffffc900032d7470
RBP: 0000000000000040 R08: ffffc900032d7497 R09: 0000000000000000
R10: ffffc900032d7460 R11: fffff5200065ae93 R12: ffff88802bef6630
R13: dffffc0000000000 R14: ffffc900032d7460 R15: 0000000000000008
FS:  0000555589313500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3c3bd71fa0 CR3: 0000000075ea6000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
 hfs_get_block+0x51c/0xbd0 fs/hfs/extent.c:366
 block_read_full_folio+0x42e/0xf40 fs/buffer.c:2406
 filemap_read_folio+0x167/0x760 mm/filemap.c:2420
 do_read_cache_folio+0x470/0x7e0 mm/filemap.c:3789
 do_read_cache_page+0x32/0x250 mm/filemap.c:3855
 read_mapping_page include/linux/pagemap.h:892 [inline]
 hfs_btree_open+0x56c/0x10c0 fs/hfs/btree.c:78
 hfs_mdb_get+0x12dc/0x2010 fs/hfs/mdb.c:199
 hfs_fill_super+0xd1d/0x1320 fs/hfs/super.c:406
 mount_bdev+0x22b/0x2d0 fs/super.c:1643
 legacy_get_tree+0xea/0x180 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x280 fs/super.c:1764
 do_new_mount+0x24b/0xa40 fs/namespace.c:3371
 do_mount fs/namespace.c:3711 [inline]
 __do_sys_mount fs/namespace.c:3920 [inline]
 __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3897
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3c3bd9030a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007ffe2df1b618 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffe2df1b6a0 RCX: 00007f3c3bd9030a
RDX: 0000200000000180 RSI: 0000200000000100 RDI: 00007ffe2df1b660
RBP: 0000200000000180 R08: 00007ffe2df1b6a0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000100
R13: 00007ffe2df1b660 R14: 00000000000002d9 R15: 0000200000000240
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:hfs_find_init+0x6a/0x1d0 fs/hfs/bfind.c:21
Code: 7e 18 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 c8 7c 87 ff 49 c7 07 00 00 00 00 48 8d 6b 40 49 89 ef 49 c1 ef 03 <43> 0f b6 04 2f 84 c0 0f 85 01 01 00 00 8b 45 00 8d 7c 00 04 be c0
RSP: 0018:ffffc900032d7388 EFLAGS: 00010202
RAX: 1ffff9200065ae8f RBX: 0000000000000000 RCX: ffff888026720000
RDX: 0000000000000000 RSI: ffffc900032d7460 RDI: ffffc900032d7470
RBP: 0000000000000040 R08: ffffc900032d7497 R09: 0000000000000000
R10: ffffc900032d7460 R11: fffff5200065ae93 R12: ffff88802bef6630
R13: dffffc0000000000 R14: ffffc900032d7460 R15: 0000000000000008
FS:  0000555589313500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3c3bd71fa0 CR3: 0000000075ea6000 CR4: 00000000003506e0
----------------
Code disassembly (best guess):
   0:	7e 18                	jle    0x1a
   2:	4c 89 f8             	mov    %r15,%rax
   5:	48 c1 e8 03          	shr    $0x3,%rax
   9:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
   e:	74 08                	je     0x18
  10:	4c 89 ff             	mov    %r15,%rdi
  13:	e8 c8 7c 87 ff       	call   0xff877ce0
  18:	49 c7 07 00 00 00 00 	movq   $0x0,(%r15)
  1f:	48 8d 6b 40          	lea    0x40(%rbx),%rbp
  23:	49 89 ef             	mov    %rbp,%r15
  26:	49 c1 ef 03          	shr    $0x3,%r15
* 2a:	43 0f b6 04 2f       	movzbl (%r15,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 01 01 00 00    	jne    0x138
  37:	8b 45 00             	mov    0x0(%rbp),%eax
  3a:	8d 7c 00 04          	lea    0x4(%rax,%rax,1),%edi
  3e:	be                   	.byte 0xbe
  3f:	c0                   	.byte 0xc0

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/02 11:06 linux-6.6.y 3a8ababb8b6a 7368264b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan general protection fault in hfs_find_init
2025/08/06 10:31 linux-6.6.y 3a8ababb8b6a ffe1dd46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in hfs_find_init
2025/08/06 10:31 linux-6.6.y 3a8ababb8b6a ffe1dd46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in hfs_find_init
2025/08/01 18:56 linux-6.6.y 3a8ababb8b6a 40127d41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in hfs_find_init
2025/08/01 18:56 linux-6.6.y 3a8ababb8b6a 40127d41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in hfs_find_init
* Struck through repros no longer work on HEAD.