UBSAN: shift-out-of-bounds in minix

UBSAN: shift-out-of-bounds in minix_statfs
Status: upstream: reported C repro on 2021/12/13 07:17
Reported-by: syzbot+5ad0824204c7bf9b67f2@syzkaller.appspotmail.com
First crash: 44d, last: 13d

Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: UBSAN: shift-out-of-bounds in minix_statfs (log)
Repro: C syz .config

Sample crash report:

loop0: detected capacity change from 0 to 272
================================================================================
UBSAN: shift-out-of-bounds in fs/minix/inode.c:380:57
shift exponent 65510 is too large for 64-bit type 'long unsigned int'
CPU: 0 PID: 3601 Comm: syz-executor657 Not tainted 5.16.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 ubsan_epilogue+0xb/0x5a lib/ubsan.c:151
 __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:330
 minix_statfs.cold+0x17/0x1c fs/minix/inode.c:380
 statfs_by_dentry+0x133/0x210 fs/statfs.c:66
 vfs_statfs fs/statfs.c:90 [inline]
 fd_statfs+0x66/0x100 fs/statfs.c:120
 __do_sys_fstatfs+0x7a/0xf0 fs/statfs.c:216
 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+0x44/0xae
RIP: 0033:0x7f33e4f00e09
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:00007ffeedacabd8 EFLAGS: 00000246 ORIG_RAX: 000000000000008a
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f33e4f00e09
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f33e4ec06a0 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffeedacaa90 R11: 0000000000000246 R12: 00007f33e4ec0730
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
================================================================================

Fix bisection attempts:
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-kasan-gce-root	2022/01/11 04:29	upstream	63045bfd3c8d	49ca1f59	.config	log	report	syz	C

Crashes (3):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-kasan-gce-root	2021/12/11 09:47	upstream	b8a98b6bf66a	49ca1f59	.config	log	report	syz	C		UBSAN: shift-out-of-bounds in minix_statfs
ci-upstream-kasan-gce-root	2021/12/11 09:24	upstream	b8a98b6bf66a	49ca1f59	.config	log	report			info	UBSAN: shift-out-of-bounds in minix_statfs
ci-upstream-linux-next-kasan-gce-root	2021/12/12 04:09	linux-next	ea922272cbe5	49ca1f59	.config	log	report			info	UBSAN: shift-out-of-bounds in minix_statfs