syzbot


UBSAN: array-index-out-of-bounds in __ocfs2_find_path

Status: upstream: reported C repro on 2025/12/15 09:34
Subsystems: ocfs2
[Documentation on labels]
Reported-by: syzbot+151afab124dfbc5f15e6@syzkaller.appspotmail.com
Fix commit: ocfs2: fix oob in __ocfs2_find_path
Patched on: [ci-upstream-linux-next-kasan-gce-root ci-upstream-rust-kasan-gce], missing on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb]
First crash: 50d, last: 14d
Cause bisection: the cause commit could be any of (bisect log):
  2f26f58df041 ocfs2: annotate flexible array members with __counted_by_le()
  cd4eaccc00d7 treewide: drop outdated compiler version remarks in Kconfig help texts
  1b34743c31fe ocfs2: add extra consistency check to ocfs2_dx_dir_lookup_rec()
  
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] ocfs2: fix oob in __ocfs2_find_path 12 (12) 2025/12/21 11:25
[syzbot] [ocfs2?] UBSAN: array-index-out-of-bounds in __ocfs2_find_path 0 (2) 2025/12/19 03:21
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 KASAN: use-after-free Read in __ocfs2_find_path origin:upstream 19 C done 11 305d 481d 3/3 fixed on 2025/05/05 12:25
upstream KASAN: use-after-free Read in __ocfs2_find_path ocfs2 19 C inconclusive 65 319d 477d 28/29 fixed on 2025/06/10 16:19
linux-6.1 KASAN: use-after-free Read in __ocfs2_find_path 19 C done 5 296d 480d 3/3 fixed on 2025/05/13 14:21
Last patch testing requests (2)
Created Duration User Patch Repo Result
2026/01/01 10:21 25m retest repro upstream report log
2025/12/19 03:21 24m heming.zhao@suse.com patch upstream OK log

Sample crash report:
loop0: detected capacity change from 0 to 32768
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/ocfs2/alloc.c:1838:11
index 0 is out of range for type 'struct ocfs2_extent_rec[] __counted_by(l_count)' (aka 'struct ocfs2_extent_rec[]')
CPU: 0 UID: 0 PID: 6062 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x40 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xe9/0xf0 lib/ubsan.c:455
 __ocfs2_find_path+0x606/0xa40 fs/ocfs2/alloc.c:1838
 ocfs2_find_leaf+0xab/0x1c0 fs/ocfs2/alloc.c:1946
 ocfs2_get_clusters_nocache+0x172/0xc60 fs/ocfs2/extent_map.c:418
 ocfs2_get_clusters+0x505/0xa70 fs/ocfs2/extent_map.c:631
 ocfs2_extent_map_get_blocks+0x202/0x6a0 fs/ocfs2/extent_map.c:678
 ocfs2_read_virt_blocks+0x286/0x930 fs/ocfs2/extent_map.c:1001
 ocfs2_read_dir_block fs/ocfs2/dir.c:521 [inline]
 ocfs2_find_entry_el fs/ocfs2/dir.c:728 [inline]
 ocfs2_find_entry+0x3e4/0x2090 fs/ocfs2/dir.c:1120
 ocfs2_find_files_on_disk+0xdf/0x310 fs/ocfs2/dir.c:2023
 ocfs2_lookup_ino_from_name+0x52/0x100 fs/ocfs2/dir.c:2045
 _ocfs2_get_system_file_inode fs/ocfs2/sysfile.c:136 [inline]
 ocfs2_get_system_file_inode+0x326/0x770 fs/ocfs2/sysfile.c:112
 ocfs2_init_global_system_inodes+0x319/0x660 fs/ocfs2/super.c:461
 ocfs2_initialize_super fs/ocfs2/super.c:2196 [inline]
 ocfs2_fill_super+0x4432/0x65b0 fs/ocfs2/super.c:993
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691
 vfs_get_tree+0x92/0x2a0 fs/super.c:1751
 fc_mount fs/namespace.c:1199 [inline]
 do_new_mount_fc fs/namespace.c:3636 [inline]
 do_new_mount+0x302/0xa10 fs/namespace.c:3712
 do_mount fs/namespace.c:4035 [inline]
 __do_sys_mount fs/namespace.c:4224 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4201
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6175f30eea
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:00007ffefc9145f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffefc914680 RCX: 00007f6175f30eea
RDX: 0000200000004440 RSI: 0000200000000340 RDI: 00007ffefc914640
RBP: 0000200000004440 R08: 00007ffefc914680 R09: 0000000000004000
R10: 0000000000004000 R11: 0000000000000246 R12: 0000200000000340
R13: 00007ffefc914640 R14: 0000000000004463 R15: 0000200000000300
 </TASK>
---[ end trace ]---

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/11 13:08 upstream d358e5254674 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-upstream-fs UBSAN: array-index-out-of-bounds in __ocfs2_find_path
2025/12/11 09:38 upstream d358e5254674 d1b870e1 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-snapshot-upstream-root UBSAN: array-index-out-of-bounds in __ocfs2_find_path
2026/01/16 05:52 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root UBSAN: array-index-out-of-bounds in __ocfs2_find_path
2026/01/16 00:00 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root UBSAN: array-index-out-of-bounds in __ocfs2_find_path
2026/01/08 10:31 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root UBSAN: array-index-out-of-bounds in __ocfs2_find_path
2026/01/04 19:53 upstream 54e82e93ca93 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root UBSAN: array-index-out-of-bounds in __ocfs2_find_path
2025/12/18 10:20 upstream ea1013c15392 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root UBSAN: array-index-out-of-bounds in __ocfs2_find_path
2025/12/16 13:38 upstream 40fbbd64bba6 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root UBSAN: array-index-out-of-bounds in __ocfs2_find_path
2025/12/11 09:24 upstream d358e5254674 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root UBSAN: array-index-out-of-bounds in __ocfs2_find_path
2026/01/03 16:28 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 UBSAN: array-index-out-of-bounds in __ocfs2_find_path
* Struck through repros no longer work on HEAD.