syzbot


UBSAN: undefined-behaviour in diReadSpecial

Status: upstream: reported C repro on 2020/09/21 20:52
Reported-by: syzbot+d435fc5677c7fbf65a9e@syzkaller.appspotmail.com
First crash: 1307d, last: 1279d
Fix bisection: failed (error log, bisect log)
  

Sample crash report:
audit: type=1400 audit(1602248837.247:8): avc:  denied  { execmem } for  pid=6499 comm="syz-executor377" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
================================================================================
UBSAN: Undefined behaviour in fs/jfs/jfs_imap.c:458:7
shift exponent -1 is negative
CPU: 1 PID: 6499 Comm: syz-executor377 Not tainted 4.19.150-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x22c/0x33e lib/dump_stack.c:118
 ubsan_epilogue+0xe/0x3a lib/ubsan.c:161
 __ubsan_handle_shift_out_of_bounds.cold+0x1c4/0x250 lib/ubsan.c:422
 diReadSpecial.cold+0x1b/0x3e fs/jfs/jfs_imap.c:458
 jfs_mount+0x83/0x3d0 fs/jfs/jfs_mount.c:98
 jfs_fill_super+0x55c/0xb50 fs/jfs/super.c:589
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
 mount_fs+0xa3/0x318 fs/super.c:1261
 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x51c/0x2f10 fs/namespace.c:2799
 ksys_mount+0xcf/0x130 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3026
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x44cb0a
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd ad fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 da ad fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007fff6e79a438 EFLAGS: 00000283 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff6e79a490 RCX: 000000000044cb0a
RDX: 0000000020000000 RSI: 000

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/10/09 13:08 linux-4.19.y a1b977b49b66 fa79ed2a .config console log report syz C ci2-linux-4-19
2020/09/22 03:45 linux-4.19.y 015e94d0e37b 9e1fa68e .config console log report syz C ci2-linux-4-19
2020/10/20 18:06 linux-4.19.y ad326970d25c ff4a3345 .config console log report info ci2-linux-4-19
2020/10/12 10:42 linux-4.19.y a1b977b49b66 4a77ae0b .config console log report info ci2-linux-4-19
2020/10/10 18:43 linux-4.19.y a1b977b49b66 b74c49a6 .config console log report info ci2-linux-4-19
2020/10/09 09:55 linux-4.19.y a1b977b49b66 fa79ed2a .config console log report info ci2-linux-4-19
2020/10/09 06:28 linux-4.19.y a1b977b49b66 92390980 .config console log report info ci2-linux-4-19
2020/09/26 17:56 linux-4.19.y 10ad6cfd5736 2d5ea0cb .config console log report info ci2-linux-4-19
2020/09/24 18:25 linux-4.19.y d09b80172c22 54289b08 .config console log report info ci2-linux-4-19
2020/09/24 16:11 linux-4.19.y d09b80172c22 54289b08 .config console log report info ci2-linux-4-19
2020/09/23 20:00 linux-4.19.y d09b80172c22 54289b08 .config console log report info ci2-linux-4-19
2020/09/23 08:01 linux-4.19.y 015e94d0e37b 287cd75a .config console log report info ci2-linux-4-19
2020/09/21 20:51 linux-4.19.y 015e94d0e37b 9e1fa68e .config console log report info ci2-linux-4-19
* Struck through repros no longer work on HEAD.