syzbot
general protection fault in open_or_create_special_dir
Status:
upstream: reported C repro on 2024/03/16 07:55
Reported-by: syzbot+0908b298a1b37b13d328@syzkaller.appspotmail.com
First crash: 861d, last: 16d
▶
▼
Last patch testing requests (10)
▶
▼
Fix bisection attempts (17)
Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000007: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f]
CPU: 1 PID: 370 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:d_really_is_positive include/linux/dcache.h:499 [inline]
RIP: 0010:open_or_create_special_dir+0x85/0x1e0 fs/incfs/vfs.c:474
Code: 1b e8 5f 2a 6b ff e9 1a 01 00 00 e8 55 2a 6b ff 48 c7 c3 ea ff ff ff e9 09 01 00 00 4c 89 f0 4c 8d 73 30 4d 89 f7 49 c1 ef 03 <41> 80 3c 07 00 74 08 4c 89 f7 e8 4c 9f a5 ff 49 83 3e 00 74 2c e8
RSP: 0018:ffffc90000cf7b60 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000008 RCX: ffff8881101f8000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888120e1fb20
RBP: ffffc90000cf7b90 R08: ffff888120e1fb27 R09: 1ffff110241c3f64
R10: dffffc0000000000 R11: ffffed10241c3f65 R12: ffff888120e1fa80
R13: ffffc90000cf7bdf R14: 0000000000000038 R15: 0000000000000007
FS: 00007fe68e0146c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe68dff2ff8 CR3: 0000000128dd8000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
incfs_mount_fs+0x434/0x8d0 fs/incfs/vfs.c:1867
legacy_get_tree+0xed/0x190 fs/fs_context.c:593
vfs_get_tree+0x89/0x260 fs/super.c:1572
do_new_mount+0x25a/0xa30 fs/namespace.c:3006
path_mount+0x581/0xca0 fs/namespace.c:3336
do_mount fs/namespace.c:3349 [inline]
__do_sys_mount fs/namespace.c:3557 [inline]
__se_sys_mount+0x320/0x390 fs/namespace.c:3534
__x64_sys_mount+0xbf/0xd0 fs/namespace.c:3534
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fe68e1b2e59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe68e014028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fe68e43afa0 RCX: 00007fe68e1b2e59
RDX: 0000200000000200 RSI: 0000200000000140 RDI: 0000200000000000
RBP: 00007fe68e248e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000082 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe68e43b038 R14: 00007fe68e43afa0 R15: 00007ffe8b9074b8
Modules linked in:
---[ end trace 972aaa6235db9134 ]---
RIP: 0010:d_really_is_positive include/linux/dcache.h:499 [inline]
RIP: 0010:open_or_create_special_dir+0x85/0x1e0 fs/incfs/vfs.c:474
Code: 1b e8 5f 2a 6b ff e9 1a 01 00 00 e8 55 2a 6b ff 48 c7 c3 ea ff ff ff e9 09 01 00 00 4c 89 f0 4c 8d 73 30 4d 89 f7 49 c1 ef 03 <41> 80 3c 07 00 74 08 4c 89 f7 e8 4c 9f a5 ff 49 83 3e 00 74 2c e8
RSP: 0018:ffffc90000cf7b60 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000008 RCX: ffff8881101f8000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888120e1fb20
RBP: ffffc90000cf7b90 R08: ffff888120e1fb27 R09: 1ffff110241c3f64
R10: dffffc0000000000 R11: ffffed10241c3f65 R12: ffff888120e1fa80
R13: ffffc90000cf7bdf R14: 0000000000000038 R15: 0000000000000007
FS: 00007fe68e0146c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe68dff2ff8 CR3: 0000000128dd8000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 1b e8 sbb %eax,%ebp
2: 5f pop %rdi
3: 2a 6b ff sub -0x1(%rbx),%ch
6: e9 1a 01 00 00 jmp 0x125
b: e8 55 2a 6b ff call 0xff6b2a65
10: 48 c7 c3 ea ff ff ff mov $0xffffffffffffffea,%rbx
17: e9 09 01 00 00 jmp 0x125
1c: 4c 89 f0 mov %r14,%rax
1f: 4c 8d 73 30 lea 0x30(%rbx),%r14
23: 4d 89 f7 mov %r14,%r15
26: 49 c1 ef 03 shr $0x3,%r15
* 2a: 41 80 3c 07 00 cmpb $0x0,(%r15,%rax,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 4c 89 f7 mov %r14,%rdi
34: e8 4c 9f a5 ff call 0xffa59f85
39: 49 83 3e 00 cmpq $0x0,(%r14)
3d: 74 2c je 0x6b
3f: e8 .byte 0xe8
* Struck through repros no longer work on HEAD.