MINIX-fs: mounting unchecked file system, running fsck is recommended
Process accounting resumed
==================================================================
BUG: KASAN: use-after-free in add_chain fs/minix/itree_common.c:14 [inline]
BUG: KASAN: use-after-free in get_branch fs/minix/itree_common.c:52 [inline]
BUG: KASAN: use-after-free in get_block+0xe06/0x1100 fs/minix/itree_common.c:160
Read of size 2 at addr ffff88807502cb1a by task syz-executor.5/32136

CPU: 0 PID: 32136 Comm: syz-executor.5 Not tainted 4.14.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1dc mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2b9 mm/kasan/report.c:393
 add_chain fs/minix/itree_common.c:14 [inline]
 get_branch fs/minix/itree_common.c:52 [inline]
 get_block+0xe06/0x1100 fs/minix/itree_common.c:160
 minix_get_block+0xd6/0x100 fs/minix/inode.c:379
 __block_write_begin_int+0x33a/0x1000 fs/buffer.c:2038
Process accounting resumed
 __block_write_begin fs/buffer.c:2088 [inline]
 block_write_begin+0x58/0x260 fs/buffer.c:2147
 minix_write_begin+0x35/0xc0 fs/minix/inode.c:415
 generic_perform_write+0x1c9/0x420 mm/filemap.c:3047
 __generic_file_write_iter+0x227/0x590 mm/filemap.c:3172
 generic_file_write_iter+0x36f/0x650 mm/filemap.c:3200
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
 __kernel_write+0xf5/0x330 fs/read_write.c:501
 do_acct_process+0xb49/0xf60 kernel/acct.c:520
 acct_pin_kill+0x28/0xe0 kernel/acct.c:174
 pin_kill+0x147/0x650 fs/fs_pin.c:50
 SYSC_acct kernel/acct.c:291 [inline]
 SyS_acct+0x5e9/0x850 kernel/acct.c:273
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45cb19
RSP: 002b:00007f3e628c6c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a3
RAX: ffffffffffffffda RBX: 00000000004d9d00 RCX: 000000000045cb19
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000001c R14: 00000000004c2ed1 R15: 00007f3e628c76d4

The buggy address belongs to the page:
page:ffffea0001d40b00 count:0 mapcount:-127 mapping:          (null) index:0x1
flags: 0xfffe0000000000()
raw: 00fffe0000000000 0000000000000000 0000000000000001 00000000ffffff80
raw: ffffea0000b29e20 ffffea0000c00120 0000000000000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88807502ca00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807502ca80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88807502cb00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                            ^
 ffff88807502cb80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807502cc00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================