FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
==================================================================
BUG: KASAN: use-after-free in atomic_dec_and_test include/asm-generic/atomic-instrumented.h:259 [inline]
BUG: KASAN: use-after-free in put_task_struct include/linux/sched/task.h:95 [inline]
BUG: KASAN: use-after-free in _free_event+0x49a/0x1610 kernel/events/core.c:4452
Write of size 4 at addr ffff88018625c260 by task syz-executor5/9641

CPU: 0 PID: 9641 Comm: syz-executor5 Not tainted 4.19.0-rc6+ #50
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278
 atomic_dec_and_test include/asm-generic/atomic-instrumented.h:259 [inline]
 put_task_struct include/linux/sched/task.h:95 [inline]
 _free_event+0x49a/0x1610 kernel/events/core.c:4452
 free_event+0xb4/0x180 kernel/events/core.c:4473
 perf_event_release_kernel+0x7d8/0xfa0 kernel/events/core.c:4634
 perf_release+0x37/0x50 kernel/events/core.c:4648
 __fput+0x385/0xa30 fs/file_table.c:278
 ____fput+0x15/0x20 fs/file_table.c:309
 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x411051
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 19 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007fffc0405af0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000411051
RDX: 0000000000000001 RSI: 0000000000730be8 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00007fffc0405a20 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 000000000000004b R15: 0000000000000005

Allocated by task 9656:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc_node+0x144/0x730 mm/slab.c:3644
 alloc_task_struct_node kernel/fork.c:157 [inline]
 dup_task_struct kernel/fork.c:802 [inline]
 copy_process+0x1ff4/0x8780 kernel/fork.c:1707
 _do_fork+0x1cb/0x11d0 kernel/fork.c:2166
 __do_sys_clone kernel/fork.c:2273 [inline]
 __se_sys_clone kernel/fork.c:2267 [inline]
 __x64_sys_clone+0xbf/0x150 kernel/fork.c:2267
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9656:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x83/0x290 mm/slab.c:3756
 free_task_struct kernel/fork.c:162 [inline]
 free_task+0x16e/0x1f0 kernel/fork.c:416
 copy_process+0x1d9a/0x8780 kernel/fork.c:2098
 _do_fork+0x1cb/0x11d0 kernel/fork.c:2166
 __do_sys_clone kernel/fork.c:2273 [inline]
 __se_sys_clone kernel/fork.c:2267 [inline]
 __x64_sys_clone+0xbf/0x150 kernel/fork.c:2267
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88018625c240
 which belongs to the cache task_struct of size 6080
The buggy address is located 32 bytes inside of
 6080-byte region [ffff88018625c240, ffff88018625da00)
The buggy address belongs to the page:
page:ffffea0006189700 count:1 mapcount:0 mapping:ffff8801da94c200 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea0006173908 ffffea0006161e08 ffff8801da94c200
raw: 0000000000000000 ffff88018625c240 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88018625c100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88018625c180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88018625c200: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                       ^
 ffff88018625c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88018625c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
CPU: 0 PID: 9675 Comm: syz-executor1 Tainted: G    B             4.19.0-rc6+ #50
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
 fail_dump lib/fault-inject.c:51 [inline]
 should_fail.cold.4+0xa/0x17 lib/fault-inject.c:149
 __should_failslab+0x124/0x180 mm/failslab.c:32
 should_failslab+0x9/0x14 mm/slab_common.c:1557
 slab_pre_alloc_hook mm/slab.h:423 [inline]
 slab_alloc mm/slab.c:3378 [inline]
 kmem_cache_alloc+0x2be/0x730 mm/slab.c:3552
 shmem_alloc_inode+0x1b/0x40 mm/shmem.c:3562
 alloc_inode+0x63/0x190 fs/inode.c:210
 new_inode_pseudo+0x71/0x1a0 fs/inode.c:903
 new_inode+0x1c/0x40 fs/inode.c:932
 shmem_get_inode+0xf1/0x920 mm/shmem.c:2186
 __shmem_file_setup.part.45+0x83/0x2a0 mm/shmem.c:3918
 __shmem_file_setup mm/shmem.c:3912 [inline]
 shmem_file_setup+0x65/0x90 mm/shmem.c:3959
 __do_sys_memfd_create mm/memfd.c:323 [inline]
 __se_sys_memfd_create mm/memfd.c:266 [inline]
 __x64_sys_memfd_create+0x2af/0x4f0 mm/memfd.c:266
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457579
Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fa6b4b06a88 EFLAGS: 00000246 ORIG_RAX: 000000000000013f
RAX: ffffffffffffffda RBX: 0000000020000540 RCX: 0000000000457579
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000004bc7c9
RBP: 000000000072bfa0 R08: 0000000000000000 R09: 00000000fbad8001
R10: 0000000020000540 R11: 0000000000000246 R12: 00007fa6b4b076d4
R13: 00000000004c4a5c R14: 00000000004d7db8 R15: 0000000000000004