FS-Cache: O-key=[10] '5e5d245b2b255d30247b'
FS-Cache: N-cookie c=000000000f51eb3f [p=000000005b05de74 fl=2 nc=0 na=1]
FS-Cache: N-cookie d=0000000009db64ee n=000000003724c62b
FS-Cache: N-key=[10] '5e5d245b2b255d30247b'
==================================================================
BUG: KASAN: use-after-free in afs_activate_cell fs/afs/cell.c:547 [inline]
BUG: KASAN: use-after-free in afs_manage_cell+0xc67/0xe50 fs/afs/cell.c:633
Write of size 8 at addr ffff8880947e70f8 by task kworker/0:2/2920

CPU: 0 PID: 2920 Comm: kworker/0:2 Not tainted 5.0.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: afs afs_manage_cell
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x165/0x21a lib/dump_stack.c:113
 print_address_description.cold.3+0x9/0x211 mm/kasan/report.c:187
 kasan_report.cold.4+0x1b/0x37 mm/kasan/report.c:317
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:140
 afs_activate_cell fs/afs/cell.c:547 [inline]
 afs_manage_cell+0xc67/0xe50 fs/afs/cell.c:633
 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2153
 worker_thread+0x85/0xb60 kernel/workqueue.c:2296
 kthread+0x324/0x3e0 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 8764:
 save_stack mm/kasan/common.c:73 [inline]
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc.part.0+0x66/0x100 mm/kasan/common.c:496
 __kasan_kmalloc.constprop.1+0xb5/0xc0 mm/kasan/common.c:477
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504
 kmem_cache_alloc_trace+0x15b/0x3d0 mm/slab.c:3609
 kmalloc include/linux/slab.h:545 [inline]
 kzalloc include/linux/slab.h:740 [inline]
 afs_alloc_cell fs/afs/cell.c:141 [inline]
 afs_lookup_cell+0x14a/0xb70 fs/afs/cell.c:229
 afs_parse_source fs/afs/super.c:272 [inline]
 afs_parse_param+0x32d/0x7c0 fs/afs/super.c:308
 vfs_parse_fs_param+0x228/0x470 fs/fs_context.c:147
 vfs_parse_fs_string+0xb8/0x110 fs/fs_context.c:190
 generic_parse_monolithic+0x117/0x190 fs/fs_context.c:230
 parse_monolithic_mount_data+0x5c/0x83 fs/fs_context.c:641
 do_new_mount fs/namespace.c:2618 [inline]
 do_mount+0x10e4/0x2ae0 fs/namespace.c:2942
 ksys_mount+0xba/0xe0 fs/namespace.c:3151
 __do_sys_mount fs/namespace.c:3165 [inline]
 __se_sys_mount fs/namespace.c:3162 [inline]
 __x64_sys_mount+0xb9/0x150 fs/namespace.c:3162
 do_syscall_64+0xd0/0x4d0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9:
 save_stack mm/kasan/common.c:73 [inline]
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x13c/0x220 mm/kasan/common.c:458
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466
 __cache_free mm/slab.c:3487 [inline]
 kfree+0xcf/0x220 mm/slab.c:3806
 afs_cell_destroy+0xd3/0x110 fs/afs/cell.c:438
 __rcu_reclaim kernel/rcu/rcu.h:240 [inline]
 rcu_do_batch kernel/rcu/tree.c:2452 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2773 [inline]
 rcu_process_callbacks+0x8a7/0x12e0 kernel/rcu/tree.c:2754
 __do_softirq+0x25e/0x958 kernel/softirq.c:292

The buggy address belongs to the object at ffff8880947e7080
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 120 bytes inside of
 512-byte region [ffff8880947e7080, ffff8880947e7280)
The buggy address belongs to the page:
page:ffffea000251f9c0 count:1 mapcount:0 mapping:ffff88812c3f6940 index:0xffff8880947e7d00
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002a28a88 ffffea000253d0c8 ffff88812c3f6940
raw: ffff8880947e7d00 ffff8880947e7080 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880947e6f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880947e7000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880947e7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff8880947e7100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880947e7180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================