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UBSAN: array-index-out-of-bounds in bch2_btree_path_traverse_cached_slowpath

Status: upstream: reported on 2024/05/28 08:13
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+fa3fc4c486ec9c342fcc@syzkaller.appspotmail.com
First crash: 18d, last: 1d08h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bcachefs?] UBSAN: array-index-out-of-bounds in bch2_btree_path_traverse_cached_slowpath 1 (2) 2024/05/29 01:46

Sample crash report:
bcachefs (loop2): alloc_read... done
bcachefs (loop2): stripes_read... done
bcachefs (loop2): snapshots_read... done
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/bcachefs/btree_key_cache.c:216:16
index 16 is out of range for type 'bkey_cached *[16]'
CPU: 0 PID: 7941 Comm: syz-executor.2 Not tainted 6.10.0-rc3-syzkaller-00044-g2ccbdf43d5e7 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:114
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_out_of_bounds+0x110/0x150 lib/ubsan.c:429
 bkey_cached_alloc fs/bcachefs/btree_key_cache.c:216 [inline]
 btree_key_cache_create fs/bcachefs/btree_key_cache.c:330 [inline]
 bch2_btree_path_traverse_cached_slowpath+0x4304/0x4d90 fs/bcachefs/btree_key_cache.c:485
 bch2_btree_path_traverse_cached+0x9ec/0xdc0 fs/bcachefs/btree_key_cache.c:588
 bch2_btree_path_traverse_one+0x16b4/0x2e40 fs/bcachefs/btree_iter.c:1153
 bch2_btree_path_traverse fs/bcachefs/btree_iter.h:229 [inline]
 bch2_btree_path_traverse fs/bcachefs/btree_iter.h:221 [inline]
 bch2_btree_iter_peek_slot+0x715/0x2450 fs/bcachefs/btree_iter.c:2598
 __bch2_bkey_get_iter fs/bcachefs/btree_iter.h:552 [inline]
 bch2_bkey_get_iter fs/bcachefs/btree_iter.h:566 [inline]
 bch2_trans_start_alloc_update_noupdate+0x6f7/0x9c0 fs/bcachefs/alloc_background.c:435
 __bch2_trans_mark_metadata_bucket.isra.0+0xf1/0x420 fs/bcachefs/buckets.c:1327
 bch2_trans_mark_metadata_bucket fs/bcachefs/buckets.c:1413 [inline]
 bch2_trans_mark_metadata_bucket+0x132/0x320 fs/bcachefs/buckets.c:1395
 bch2_trans_mark_metadata_sectors.constprop.0+0x1a3/0x250 fs/bcachefs/buckets.c:1430
 __bch2_trans_mark_dev_sb fs/bcachefs/buckets.c:1465 [inline]
 bch2_trans_mark_dev_sb+0x1fe/0x6a0 fs/bcachefs/buckets.c:1493
 bch2_trans_mark_dev_sbs_flags fs/bcachefs/buckets.c:1503 [inline]
 bch2_trans_mark_dev_sbs+0x28/0x320 fs/bcachefs/buckets.c:1515
 bch2_run_recovery_pass+0x8e/0x1a0 fs/bcachefs/recovery_passes.c:182
 bch2_run_recovery_passes+0x33b/0x710 fs/bcachefs/recovery_passes.c:225
 bch2_fs_recovery+0x259f/0x3db0 fs/bcachefs/recovery.c:807
 bch2_fs_start+0x2e9/0x600 fs/bcachefs/super.c:1035
 bch2_fs_open+0xde0/0x10f0 fs/bcachefs/super.c:2127
 bch2_mount+0xe0c/0x11a0 fs/bcachefs/fs.c:1919
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8f/0x380 fs/super.c:1780
 do_new_mount fs/namespace.c:3352 [inline]
 path_mount+0x6e1/0x1f10 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount fs/namespace.c:3875 [inline]
 __ia32_sys_mount+0x295/0x320 fs/namespace.c:3875
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf725a579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f5e4c400 EFLAGS: 00000292 ORIG_RAX: 0000000000000015
RAX: ffffffffffffffda RBX: 00000000f5e4c460 RCX: 0000000020000040
RDX: 0000000020011a00 RSI: 0000000001200014 RDI: 00000000f5e4c4a0
RBP: 00000000f5e4c460 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
---[ end trace ]---
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	10 06                	adc    %al,(%rsi)
   2:	03 74 b4 01          	add    0x1(%rsp,%rsi,4),%esi
   6:	10 07                	adc    %al,(%rdi)
   8:	03 74 b0 01          	add    0x1(%rax,%rsi,4),%esi
   c:	10 08                	adc    %cl,(%rax)
   e:	03 74 d8 01          	add    0x1(%rax,%rbx,8),%esi
  1e:	00 51 52             	add    %dl,0x52(%rcx)
  21:	55                   	push   %rbp
  22:	89 e5                	mov    %esp,%ebp
  24:	0f 34                	sysenter
  26:	cd 80                	int    $0x80
* 28:	5d                   	pop    %rbp <-- trapping instruction
  29:	5a                   	pop    %rdx
  2a:	59                   	pop    %rcx
  2b:	c3                   	ret
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	90                   	nop
  2f:	90                   	nop
  30:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
  37:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/13 19:47 upstream 2ccbdf43d5e7 c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 UBSAN: array-index-out-of-bounds in bch2_btree_path_traverse_cached_slowpath
2024/06/08 00:31 upstream 96e09b8f8166 c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 UBSAN: array-index-out-of-bounds in bch2_btree_path_traverse_cached_slowpath
2024/05/27 20:07 upstream 2bfcfd584ff5 c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 UBSAN: array-index-out-of-bounds in bch2_btree_path_traverse_cached_slowpath
* Struck through repros no longer work on HEAD.