[syzbot] UBSAN: shift-out-of-bounds in minix_count_free_blocks

[syzbot <syzbot+2f142b57f2af27974fda@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    23d04328444a Merge tag 'for-5.17/parisc-4' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1275258e700000
kernel config:  https://syzkaller.appspot.com/x/.config?x=15187fc11a461d83
dashboard link: https://syzkaller.appspot.com/bug?extid=2f142b57f2af27974fda
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=134ea112700000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1038b52e700000

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=132d548e700000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=10ad548e700000
console output: https://syzkaller.appspot.com/x/log.txt?x=172d548e700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2f142b57f2af27974fda@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 24
MINIX-fs: mounting unchecked file system, running fsck is recommended
================================================================================
UBSAN: shift-out-of-bounds in fs/minix/bitmap.c:103:3
shift exponent 34 is too large for 32-bit type 'unsigned int'
CPU: 0 PID: 3594 Comm: syz-executor300 Not tainted 5.17.0-rc5-syzkaller-00021-g23d04328444a #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+0xb1/0x187 lib/ubsan.c:330
 minix_count_free_blocks.cold+0x16/0x1b fs/minix/bitmap.c:103
 minix_statfs+0x22a/0x490 fs/minix/inode.c:381
 statfs_by_dentry+0x133/0x210 fs/statfs.c:66
 vfs_statfs fs/statfs.c:90 [inline]
 user_statfs+0xa9/0x160 fs/statfs.c:105
 __do_sys_statfs+0x7a/0xf0 fs/statfs.c:195
 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: 0033:0x7ff02930fdd9
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:00007ffe6c051938 EFLAGS: 00000246 ORIG_RAX: 0000000000000089
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007ff02930fdd9
RDX: 00007ff0292ce3a3 RSI: 0000000000000000 RDI: 0000000020000140
RBP: 00007ff0292cf670 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffe6c051800 R11: 0000000000000246 R12: 00007ff0292cf700
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
================================================================================


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