syzbot


general protection fault in bch2_prt_vprintf

Status: upstream: reported C repro on 2024/11/29 08:43
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+03b7bb8ca037d17926dc@syzkaller.appspotmail.com
First crash: 5d03h, last: 14h10m
Cause bisection: failed (error log, bisect log)
  
Discussions (1)
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[syzbot] [bcachefs?] general protection fault in bch2_prt_vprintf 0 (1) 2024/11/29 08:43

Sample crash report:
  bi_fields_set=0
  bi_dir=4096
  bi_dir_offset=2695648408715017799
  bi_subvol=0
  bi_parent_subvol=0
  bi_nocow=0, fixing
Oops: general protection fault, probably for non-canonical address 0xec6408ae4eae6c2e: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: maybe wild-memory-access in range [0x6320657275736170-0x6320657275736177]
CPU: 0 UID: 0 PID: 5828 Comm: syz-executor420 Not tainted 6.13.0-rc1-syzkaller-00005-gceb8bf2ceaa7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:string_nocheck lib/vsprintf.c:646 [inline]
RIP: 0010:string+0x1a5/0x2b0 lib/vsprintf.c:728
Code: 85 c0 0f 84 db 00 00 00 4c 89 7c 24 08 49 89 c7 49 ff cf 31 db 49 8d 3c 1c 48 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 75 5d 4c 8d 6c 1d 00 41 0f b6 2c 1c 31 ff 89 ee
RSP: 0018:ffffc90003d26570 EFLAGS: 00010206
RAX: 0c640cae4eae6c2e RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88802ffabc00 RSI: ffffffffffffffff RDI: 6320657275736172
RBP: 0000000000000020 R08: ffffffff8bc3c8b7 R09: ffffffff8bc38f54
R10: 0000000000000012 R11: ffff88802ffabc00 R12: 6320657275736172
R13: 0000000000000000 R14: 0000000000000020 R15: fffffffffffffffe
FS:  000055558715a380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562d64415048 CR3: 000000007ac96000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 vsnprintf+0x1101/0x1da0 lib/vsprintf.c:2848
 bch2_prt_vprintf+0x1a2/0x700 fs/bcachefs/printbuf.c:166
 __bch2_fsck_err+0x2c2/0x1570 fs/bcachefs/error.c:266
 check_dirent_inode_dirent+0xf3b/0x1a30 fs/bcachefs/fsck.c:2214
 check_dirent_target+0x117/0xf70 fs/bcachefs/fsck.c:2244
 check_dirent fs/bcachefs/fsck.c:2518 [inline]
 bch2_check_dirents+0x12e9/0x2570 fs/bcachefs/fsck.c:2552
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:191
 bch2_run_recovery_passes+0x3a7/0x880 fs/bcachefs/recovery_passes.c:244
 bch2_fs_recovery+0x25cc/0x39d0 fs/bcachefs/recovery.c:861
 bch2_fs_start+0x356/0x5b0 fs/bcachefs/super.c:1037
 bch2_fs_get_tree+0xd68/0x1710 fs/bcachefs/fs.c:2170
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3507
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
 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: 0033:0x7f935bd4d8fa
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcad1bf668 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffcad1bf680 RCX: 00007f935bd4d8fa
RDX: 00000000200058c0 RSI: 0000000020000000 RDI: 00007ffcad1bf680
RBP: 0000000000000004 R08: 00007ffcad1bf6c0 R09: 00000000000059aa
R10: 0000000000010040 R11: 0000000000000282 R12: 0000000000010040
R13: 00007ffcad1bf6c0 R14: 0000000000000003 R15: 0000000001000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:string_nocheck lib/vsprintf.c:646 [inline]
RIP: 0010:string+0x1a5/0x2b0 lib/vsprintf.c:728
Code: 85 c0 0f 84 db 00 00 00 4c 89 7c 24 08 49 89 c7 49 ff cf 31 db 49 8d 3c 1c 48 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 75 5d 4c 8d 6c 1d 00 41 0f b6 2c 1c 31 ff 89 ee
RSP: 0018:ffffc90003d26570 EFLAGS: 00010206
RAX: 0c640cae4eae6c2e RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88802ffabc00 RSI: ffffffffffffffff RDI: 6320657275736172
RBP: 0000000000000020 R08: ffffffff8bc3c8b7 R09: ffffffff8bc38f54
R10: 0000000000000012 R11: ffff88802ffabc00 R12: 6320657275736172
R13: 0000000000000000 R14: 0000000000000020 R15: fffffffffffffffe
FS:  000055558715a380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562d64416018 CR3: 000000007ac96000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	85 c0                	test   %eax,%eax
   2:	0f 84 db 00 00 00    	je     0xe3
   8:	4c 89 7c 24 08       	mov    %r15,0x8(%rsp)
   d:	49 89 c7             	mov    %rax,%r15
  10:	49 ff cf             	dec    %r15
  13:	31 db                	xor    %ebx,%ebx
  15:	49 8d 3c 1c          	lea    (%r12,%rbx,1),%rdi
  19:	48 89 f8             	mov    %rdi,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	0f b6 04 08          	movzbl (%rax,%rcx,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	75 5d                	jne    0x8f
  32:	4c 8d 6c 1d 00       	lea    0x0(%rbp,%rbx,1),%r13
  37:	41 0f b6 2c 1c       	movzbl (%r12,%rbx,1),%ebp
  3c:	31 ff                	xor    %edi,%edi
  3e:	89 ee                	mov    %ebp,%esi

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/03 19:00 upstream ceb8bf2ceaa7 578925bc .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs general protection fault in bch2_prt_vprintf
2024/11/29 07:19 upstream 65ae975e97d5 5df23865 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root general protection fault in bch2_prt_vprintf
2024/11/29 06:43 upstream 65ae975e97d5 5df23865 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root general protection fault in bch2_prt_vprintf
2024/11/29 06:07 upstream 65ae975e97d5 5df23865 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in bch2_prt_vprintf
* Struck through repros no longer work on HEAD.