Process accounting resumed
MINIX-fs: mounting unchecked file system, running fsck is recommended
Process accounting resumed
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+0xe7c/0x10f0 fs/minix/itree_common.c:160
Read of size 2 at addr ffff8881f44efbb8 by task syz-executor.1/20584

CPU: 1 PID: 20584 Comm: syz-executor.1 Not tainted 4.14.177-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+0x13e/0x194 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1e2 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+0xa9/0x2ae 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+0xe7c/0x10f0 fs/minix/itree_common.c:160
 minix_get_block+0xd6/0x100 fs/minix/inode.c:379
 __block_write_begin_int+0x337/0x1030 fs/buffer.c:2038
 __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+0x2fa/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
 mnt_pin_kill+0x62/0x170 fs/fs_pin.c:87
 cleanup_mnt+0x110/0x140 fs/namespace.c:1180
 task_work_run+0x113/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1d6/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c829
RSP: 002b:00007fede3f72c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000509bc0 RCX: 000000000045c829
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000500
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000c42 R14: 00000000004ce717 R15: 00007fede3f736d4

The buggy address belongs to the page:
page:ffffea0007d13bc0 count:0 mapcount:0 mapping:          (null) index:0x1
flags: 0x57ffe0000000000()
raw: 057ffe0000000000 0000000000000000 0000000000000001 00000000ffffffff
raw: ffffea0007d259a0 ffffea0007d25920 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881f44efa80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881f44efb00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881f44efb80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                        ^
 ffff8881f44efc00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881f44efc80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================