syzbot


UBSAN: shift-out-of-bounds in dbSplit

Status: upstream: reported C repro on 2022/10/04 09:00
Reported-by: syzbot+8c777e17f74c66068ffa@syzkaller.appspotmail.com
First crash: 66d, last: 30d

Cause bisection: failed (bisect log)

Sample crash report:
loop0: detected capacity change from 0 to 32768
================================================================================
UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:2606:11
shift exponent 109 is too large for 32-bit type 'int'
CPU: 1 PID: 3606 Comm: syz-executor198 Not tainted 6.0.0-syzkaller-06475-g4c86114194e6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 ubsan_epilogue+0xb/0x50 lib/ubsan.c:151
 __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x187 lib/ubsan.c:322
 dbSplit.cold+0x19/0x1e fs/jfs/jfs_dmap.c:2606
 dbAllocBits+0x14f/0x5f0 fs/jfs/jfs_dmap.c:2158
 dbAllocDmap+0x61/0x110 fs/jfs/jfs_dmap.c:1999
 dbAllocNear fs/jfs/jfs_dmap.c:1228 [inline]
 dbAlloc+0x78a/0xa70 fs/jfs/jfs_dmap.c:813
 diNewExt+0x724/0x1a10 fs/jfs/jfs_imap.c:2251
 diAllocExt fs/jfs/jfs_imap.c:1945 [inline]
 diAllocAG+0x15f1/0x2200 fs/jfs/jfs_imap.c:1662
 diAlloc+0x82d/0x1730 fs/jfs/jfs_imap.c:1583
 ialloc+0x89/0xaa0 fs/jfs/jfs_inode.c:56
 jfs_mkdir+0x1f0/0xab0 fs/jfs/namei.c:225
 vfs_mkdir+0x489/0x740 fs/namei.c:4013
 do_mkdirat+0x28c/0x310 fs/namei.c:4038
 __do_sys_mkdir fs/namei.c:4058 [inline]
 __se_sys_mkdir fs/namei.c:4056 [inline]
 __x64_sys_mkdir+0xf2/0x140 fs/namei.c:4056
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fc71381edc9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc4f441de8 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc71381edc9
RDX: 00007fc7137dd2c3 RSI: 0000000000000000 RDI: 00000000200052c0
RBP: 00007fc7137de590 R08: 00005555573bd2c0 R09: 0000000000000000
R10: 00007ffc4f441cb0 R11: 0000000000000246 R12: 00000000f8008000
R13: 0000000000000000 R14: 00080000000000fc R15: 0000000000000000
 </TASK>
================================================================================

Fix bisection attempts:
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-fs 2022/11/07 14:21 upstream f0c4d9fc9cc9 feb56351 .config log report syz C
* Struck through repros no longer work on HEAD.
Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2022/10/08 06:31 upstream 4c86114194e6 0de35f24 .config log report syz C UBSAN: shift-out-of-bounds in dbSplit
ci2-upstream-fs 2022/10/02 17:40 upstream b357fd1c2afc feb56351 .config log report syz C UBSAN: shift-out-of-bounds in dbSplit
* Struck through repros no longer work on HEAD.