RBP: 000000000072bea0 R08: 0000000020000080 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 0000000000000006
R13: 00000000004bb85d R14: 00000000004c8d28 R15: 000000000000000c
trace_kprobe: Failed to allocate trace_uprobe.(-12)
==================================================================
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/0x15e0 kernel/events/core.c:4451
Write of size 4 at addr ffff8801d7b300a0 by task syz-executor3/4578

CPU: 1 PID: 4578 Comm: syz-executor3 Not tainted 4.18.0-rc5-next-20180720+ #12
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+0x1c9/0x2b4 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x30d 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/0x15e0 kernel/events/core.c:4451
 free_event+0xb4/0x180 kernel/events/core.c:4472
 perf_event_release_kernel+0x7d5/0xfc0 kernel/events/core.c:4633
 perf_release+0x37/0x50 kernel/events/core.c:4647
 __fput+0x376/0x8a0 fs/file_table.c:279
 ____fput+0x15/0x20 fs/file_table.c:312
 task_work_run+0x1ec/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: 0033:0x40fb91
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:00007ffd21ab83b0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 000000000040fb91
RDX: 0000000000000000 RSI: 0000000000730ad8 RDI: 0000000000000004
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffd21ab8230 R11: 0000000000000293 R12: 00000000000003e0
R13: 0000000000000000 R14: 00007ffd21ab8a60 R15: 0000000000000000

Allocated by task 4589:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc_node+0x144/0x780 mm/slab.c:3644
 alloc_task_struct_node kernel/fork.c:158 [inline]
 dup_task_struct kernel/fork.c:780 [inline]
 copy_process.part.41+0x176a/0x73d0 kernel/fork.c:1653
 copy_process kernel/fork.c:1628 [inline]
 _do_fork+0x291/0x12a0 kernel/fork.c:2117
 __do_sys_clone kernel/fork.c:2224 [inline]
 __se_sys_clone kernel/fork.c:2218 [inline]
 __x64_sys_clone+0xbf/0x150 kernel/fork.c:2218
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 4589:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 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+0x86/0x2d0 mm/slab.c:3756
 free_task_struct kernel/fork.c:163 [inline]
 free_task+0x16e/0x1f0 kernel/fork.c:391
 copy_process.part.41+0x167e/0x73d0 kernel/fork.c:2052
 copy_process kernel/fork.c:1628 [inline]
 _do_fork+0x291/0x12a0 kernel/fork.c:2117
 __do_sys_clone kernel/fork.c:2224 [inline]
 __se_sys_clone kernel/fork.c:2218 [inline]
 __x64_sys_clone+0xbf/0x150 kernel/fork.c:2218
 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 ffff8801d7b30080
 which belongs to the cache task_struct(49:syz3) of size 6016
The buggy address is located 32 bytes inside of
 6016-byte region [ffff8801d7b30080, ffff8801d7b31800)
The buggy address belongs to the page:
page:ffffea00075ecc00 count:1 mapcount:0 mapping:ffff8801d81554c0 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000010200(slab|head)
raw: 02fffc0000010200 ffffea0006ac5c08 ffff8801ccf28548 ffff8801d81554c0
raw: 0000000000000000 ffff8801d7b30080 0000000100000001 ffff8801d7c06bc0
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff8801d7c06bc0

Memory state around the buggy address:
 ffff8801d7b2ff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8801d7b30000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801d7b30080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff8801d7b30100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d7b30180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================