FS-Cache: Duplicate cookie detected FS-Cache: O-cookie c=000000003d2a6c08 [p=000000003121f816 fl=222 nc=0 na=1] FS-Cache: O-cookie d=000000001b9881e7 n=00000000e034fbc8 FS-Cache: O-key=[5] '23ee2ea1fb' FS-Cache: N-cookie c=00000000f5e1336a [p=000000003121f816 fl=2 nc=0 na=1] FS-Cache: N-cookie d=000000001b9881e7 n=000000005793e511 FS-Cache: N-key=[5] '23ee2ea1fb' ================================================================== BUG: KASAN: use-after-free in afs_activate_cell fs/afs/cell.c:609 [inline] BUG: KASAN: use-after-free in afs_manage_cell+0xea0/0x11c0 fs/afs/cell.c:697 Write of size 8 at addr ffff8880a6194890 by task kworker/0:4/14981 CPU: 0 PID: 14981 Comm: kworker/0:4 Not tainted 5.9.0-rc2-next-20200825-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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 afs_activate_cell fs/afs/cell.c:609 [inline] afs_manage_cell+0xea0/0x11c0 fs/afs/cell.c:697 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Allocated by task 22737: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 kmem_cache_alloc_trace+0x16e/0x2c0 mm/slab.c:3550 kmalloc include/linux/slab.h:554 [inline] kzalloc include/linux/slab.h:666 [inline] afs_alloc_cell fs/afs/cell.c:151 [inline] afs_lookup_cell+0x5c8/0x1440 fs/afs/cell.c:262 afs_parse_source fs/afs/super.c:290 [inline] afs_parse_param+0x404/0x8c0 fs/afs/super.c:326 vfs_parse_fs_param fs/fs_context.c:117 [inline] vfs_parse_fs_param+0x203/0x550 fs/fs_context.c:98 vfs_parse_fs_string+0xe6/0x150 fs/fs_context.c:161 generic_parse_monolithic+0x16f/0x1f0 fs/fs_context.c:201 do_new_mount fs/namespace.c:2892 [inline] path_mount+0x123f/0x1e20 fs/namespace.c:3214 do_mount fs/namespace.c:3227 [inline] __do_sys_mount fs/namespace.c:3435 [inline] __se_sys_mount fs/namespace.c:3412 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3412 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 9: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kfree+0x103/0x2c0 mm/slab.c:3756 rcu_do_batch kernel/rcu/tree.c:2474 [inline] rcu_core+0x61e/0x1220 kernel/rcu/tree.c:2709 __do_softirq+0x2de/0xa24 kernel/softirq.c:298 Last call_rcu(): kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_record_aux_stack+0x82/0xb0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2951 [inline] call_rcu+0x14f/0x7f0 kernel/rcu/tree.c:3025 afs_manage_cell+0x250/0x11c0 fs/afs/cell.c:751 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Second to last call_rcu(): kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_record_aux_stack+0x82/0xb0 mm/kasan/generic.c:346 __call_rcu kernel/rcu/tree.c:2951 [inline] call_rcu+0x14f/0x7f0 kernel/rcu/tree.c:3025 __bpf_prog_put_noref kernel/bpf/syscall.c:1733 [inline] __bpf_prog_put_noref kernel/bpf/syscall.c:1726 [inline] __bpf_prog_put.constprop.0+0x1e8/0x250 kernel/bpf/syscall.c:1745 bpf_prog_put kernel/bpf/syscall.c:1751 [inline] bpf_prog_release+0x33/0x40 kernel/bpf/syscall.c:1759 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:141 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:140 [inline] exit_to_user_mode_prepare+0x195/0x1c0 kernel/entry/common.c:167 syscall_exit_to_user_mode+0x59/0x2b0 kernel/entry/common.c:242 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8880a6194800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 144 bytes inside of 1024-byte region [ffff8880a6194800, ffff8880a6194c00) The buggy address belongs to the page: page:0000000013bf125d refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a6194000 pfn:0xa6194 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00023f21c8 ffffea00029d0088 ffff8880aa040700 raw: ffff8880a6194000 ffff8880a6194000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a6194780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a6194800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a6194880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a6194900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a6194980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================