syzbot


UBSAN: shift-out-of-bounds in ext4_fill_super

Status: upstream: reported C repro on 2023/12/25 17:58
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+f358aa23cf81d2593253@syzkaller.appspotmail.com
First crash: 201d, last: 19d
Bug presence (2)
Date Name Commit Repro Result
2023/12/25 lts (merge base) 9b91d36ba301 C [report] UBSAN: shift-out-of-bounds in ext4_fill_super
2023/12/25 upstream (ToT) 861deac3b092 C [report] UBSAN: shift-out-of-bounds in ext4_handle_clustersize
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream UBSAN: shift-out-of-bounds in ext4_fill_super ext4 C unreliable 88 1297d 1313d 19/27 fixed on 2021/03/10 01:48
Last patch testing requests (1)
Created Duration User Patch Repo Result
2024/01/08 18:07 5m retest repro android13-5.15-lts report log
Fix bisection attempts (5)
Created Duration User Patch Repo Result
2024/06/24 20:27 58m bisect fix android13-5.15-lts OK (0) job log log
2024/05/16 20:27 35m bisect fix android13-5.15-lts OK (0) job log log
2024/04/12 21:32 2h01m bisect fix android13-5.15-lts OK (0) job log log
2024/03/10 18:42 34m bisect fix android13-5.15-lts OK (0) job log log
2024/02/09 14:26 37m bisect fix android13-5.15-lts OK (0) job log log

Sample crash report:
loop5: detected capacity change from 0 to 512
================================================================================
UBSAN: shift-out-of-bounds in fs/ext4/super.c:4423:27
shift exponent 59 is too large for 32-bit type 'int'
CPU: 0 PID: 572 Comm: syz-executor170 Not tainted 5.15.141-syzkaller-00899-g28e3f5851a99 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x151/0x1b7 lib/dump_stack.c:106
 dump_stack+0x15/0x17 lib/dump_stack.c:113
 ubsan_epilogue lib/ubsan.c:151 [inline]
 __ubsan_handle_shift_out_of_bounds+0x3bf/0x420 lib/ubsan.c:321
 ext4_fill_super+0x7491/0x96e0 fs/ext4/super.c:4423
 mount_bdev+0x282/0x3b0 fs/super.c:1387
 ext4_mount+0x34/0x40 fs/ext4/super.c:6581
 legacy_get_tree+0xf1/0x190 fs/fs_context.c:611
 vfs_get_tree+0x88/0x290 fs/super.c:1517
 do_new_mount+0x28b/0xad0 fs/namespace.c:2994
 path_mount+0x671/0x1070 fs/namespace.c:3324
 do_mount fs/namespace.c:3337 [inline]
 __do_sys_mount fs/namespace.c:3545 [inline]
 __se_sys_mount+0x2c4/0x3b0 fs/namespace.c:3522
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3522
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f0c4a25309a
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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0c4a20e088 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f0c4a25309a
RDX: 0000000020000040 RSI: 0000000020000080 RDI: 00007f0c4a20e0a0
RBP: 00007f0c4a20e0a0 R08: 00007f0c4a20e0e0 R09: 00000000000004d6
R10: 0000000000004500 R11: 0000000000000202 R12: 00007f0c4a20e0e0
R13: 0000000000004500 R14: 0000000000000003 R15: 0000000000040000
 </TASK>
================================================================================
EXT4-fs (loop5): fragment/cluster size (0) != block size (4096)

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/12/25 17:57 android13-5.15-lts 28e3f5851a99 fb427a07 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-5-15 UBSAN: shift-out-of-bounds in ext4_fill_super
* Struck through repros no longer work on HEAD.