syzbot

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BUG: KASAN: use-after-free in atomic_dec_and_test include/asm-generic/atomic-instrumented.h:222 [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+0x48d/0x1440 kernel/events/core.c:4451
Write of size 4 at addr ffff8801aab60760 by task syz-executor361/6988

CPU: 1 PID: 6988 Comm: syz-executor361 Not tainted 4.18.0-rc5+ #159
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+0x242/0x2fe 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:222 [inline]
 put_task_struct include/linux/sched/task.h:95 [inline]
 _free_event+0x48d/0x1440 kernel/events/core.c:4451
 free_event+0xb4/0x180 kernel/events/core.c:4472
 perf_event_release_kernel+0x7d5/0x1050 kernel/events/core.c:4633
 perf_release+0x37/0x50 kernel/events/core.c:4647
 __fput+0x355/0x8b0 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x1ec/0x2a0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x1b08/0x2750 kernel/exit.c:865
 do_group_exit+0x177/0x440 kernel/exit.c:968
 get_signal+0x88e/0x1970 kernel/signal.c:2468
 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816
 exit_to_usermode_loop+0x2e0/0x370 arch/x86/entry/common.c:162
 prepare_exit_to_usermode+0x342/0x3b0 arch/x86/entry/common.c:197
 retint_user+0x8/0x18
RIP: 0033:0x445ea5
Code: 80 00 00 00 00 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 fb 0d fc ff <c3> 66 2e 0f 1f 84 00 00 00 00 00 48 85 ff 41 57 4d 89 cf 41 56 41 
RSP: 002b:0000000020000040 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00000000006dbc24 RCX: 0000000000445e99
RDX: 0000000020000100 RSI: 0000000020000040 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000020000080 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 00000000006dbc20
R13: 0030656c69662f2e R14: 0001000000000002 R15: 0000000000000006

Allocated by task 6959:
 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:157 [inline]
 dup_task_struct kernel/fork.c:804 [inline]
 copy_process.part.39+0x16a1/0x70b0 kernel/fork.c:1666
 copy_process kernel/fork.c:1641 [inline]
 _do_fork+0x291/0x12a0 kernel/fork.c:2124
 __do_sys_clone kernel/fork.c:2231 [inline]
 __se_sys_clone kernel/fork.c:2225 [inline]
 __x64_sys_clone+0xbf/0x150 kernel/fork.c:2225
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6959:
 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:162 [inline]
 free_task+0x16e/0x1f0 kernel/fork.c:417
 copy_process.part.39+0x15b5/0x70b0 kernel/fork.c:2059
 copy_process kernel/fork.c:1641 [inline]
 _do_fork+0x291/0x12a0 kernel/fork.c:2124
 __do_sys_clone kernel/fork.c:2231 [inline]
 __se_sys_clone kernel/fork.c:2225 [inline]
 __x64_sys_clone+0xbf/0x150 kernel/fork.c:2225
 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 ffff8801aab60740
 which belongs to the cache task_struct of size 5952
The buggy address is located 32 bytes inside of
 5952-byte region [ffff8801aab60740, ffff8801aab61e80)
The buggy address belongs to the page:
page:ffffea0006aad800 count:1 mapcount:0 mapping:ffff8801da94b200 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea0007592388 ffffea0006aa2a08 ffff8801da94b200
raw: 0000000000000000 ffff8801aab60740 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801aab60600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801aab60680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801aab60700: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                       ^
 ffff8801aab60780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801aab60800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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