[syzbot] UBSAN: array-index-out-of-bounds in udf_statfs

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    e77a830c Merge branch 'akpm' (patches from Andrew)
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14c63e6dd00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c0a6882014fd3d45
dashboard link: https://syzkaller.appspot.com/bug?extid=7fbfe5fed73ebb675748
compiler:       Debian clang version 11.0.1-2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17612825d00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=132cb56dd00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7fbfe5fed73ebb675748@xxxxxxxxxxxxxxxxxxxxxxxxx

loop0: detected capacity change from 0 to 3974
UDF-fs: INFO Mounting volume 'LinuxUDF', timestamp 2020/09/19 18:44 (1000)
================================================================================
UBSAN: array-index-out-of-bounds in fs/udf/super.c:2524:12
index 0 is out of range for type '__le32 [0]'
CPU: 1 PID: 8363 Comm: syz-executor557 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x202/0x31e lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:148 [inline]
 __ubsan_handle_out_of_bounds+0xdb/0x130 lib/ubsan.c:288
 udf_count_free fs/udf/super.c:2524 [inline]
 udf_statfs+0x49f/0xd70 fs/udf/super.c:2408
 statfs_by_dentry fs/statfs.c:66 [inline]
 vfs_statfs+0x136/0x310 fs/statfs.c:90
 user_statfs fs/statfs.c:105 [inline]
 __do_sys_statfs fs/statfs.c:195 [inline]
 __se_sys_statfs+0xe5/0x210 fs/statfs.c:192
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x444579
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:00007ffc428d7b58 EFLAGS: 00000246 ORIG_RAX: 0000000000000089
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 0000000000444579
RDX: 0000000000402b43 RSI: 0000000000000000 RDI: 00000000200001c0
RBP: 0000000000403e10 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffc428d7a20 R11: 0000000000000246 R12: 0000000000403ea0
R13: 0000000000000000 R14: 00000000004b2018 R15: 00000000004004a0
================================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 8363 Comm: syz-executor557 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x202/0x31e lib/dump_stack.c:120
 panic+0x2e1/0x850 kernel/panic.c:231
 ubsan_epilogue lib/ubsan.c:162 [inline]
 __ubsan_handle_out_of_bounds+0x12b/0x130 lib/ubsan.c:288
 udf_count_free fs/udf/super.c:2524 [inline]
 udf_statfs+0x49f/0xd70 fs/udf/super.c:2408
 statfs_by_dentry fs/statfs.c:66 [inline]
 vfs_statfs+0x136/0x310 fs/statfs.c:90
 user_statfs fs/statfs.c:105 [inline]
 __do_sys_statfs fs/statfs.c:195 [inline]
 __se_sys_statfs+0xe5/0x210 fs/statfs.c:192
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x444579
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:00007ffc428d7b58 EFLAGS: 00000246 ORIG_RAX: 0000000000000089
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 0000000000444579
RDX: 0000000000402b43 RSI: 0000000000000000 RDI: 00000000200001c0
RBP: 0000000000403e10 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffc428d7a20 R11: 0000000000000246 R12: 0000000000403ea0
R13: 0000000000000000 R14: 00000000004b2018 R15: 00000000004004a0
Kernel Offset: disabled
Rebooting in 86400 seconds..


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