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BUG: KASAN: use-after-free in memcpy include/linux/string.h:344 [inline]
BUG: KASAN: use-after-free in array_map_update_elem+0x197/0x240 kernel/bpf/arraymap.c:249
Write of size 4 at addr ffff8801d1db3428 by task syz-executor5/26983

CPU: 1 PID: 26983 Comm: syz-executor5 Not tainted 4.15.0-rc8+ #264
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
 memcpy+0x37/0x50 mm/kasan/kasan.c:303
 memcpy include/linux/string.h:344 [inline]
 array_map_update_elem+0x197/0x240 kernel/bpf/arraymap.c:249
 map_update_elem kernel/bpf/syscall.c:687 [inline]
 SYSC_bpf kernel/bpf/syscall.c:1714 [inline]
 SyS_bpf+0x32df/0x4400 kernel/bpf/syscall.c:1685
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x452df9
RSP: 002b:00007f9e6f333c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f9e6f334700 RCX: 0000000000452df9
RDX: 0000000000000020 RSI: 000000002081c000 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
R13: 0000000000a2f7ef R14: 00007f9e6f3349c0 R15: 0000000000000000

Allocated by task 4614:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3544
 anon_vma_chain_alloc mm/rmap.c:128 [inline]
 anon_vma_clone+0x139/0x700 mm/rmap.c:268
 anon_vma_fork+0xe4/0x870 mm/rmap.c:331
 dup_mmap kernel/fork.c:670 [inline]
 dup_mm kernel/fork.c:1196 [inline]
 copy_mm+0xb4d/0x131b kernel/fork.c:1250
 copy_process.part.38+0x1ee9/0x4b20 kernel/fork.c:1752
 copy_process kernel/fork.c:1565 [inline]
 _do_fork+0x1f7/0xfe0 kernel/fork.c:2044
 SYSC_clone kernel/fork.c:2154 [inline]
 SyS_clone+0x37/0x50 kernel/fork.c:2148
 do_syscall_64+0x273/0x920 arch/x86/entry/common.c:285
 return_from_SYSCALL_64+0x0/0x75

Freed by task 20090:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3488 [inline]
 kmem_cache_free+0x83/0x2a0 mm/slab.c:3746
 anon_vma_chain_free mm/rmap.c:133 [inline]
 unlink_anon_vmas+0x20d/0x9f0 mm/rmap.c:400
 free_pgtables+0xe7/0x330 mm/memory.c:621
 exit_mmap+0x291/0x500 mm/mmap.c:3039
 __mmput kernel/fork.c:923 [inline]
 mmput+0x223/0x6d0 kernel/fork.c:944
 exit_mm kernel/exit.c:544 [inline]
 do_exit+0x90a/0x1ad0 kernel/exit.c:852
 do_group_exit+0x149/0x400 kernel/exit.c:968
 get_signal+0x73f/0x16c0 kernel/signal.c:2335
 do_signal+0x90/0x1eb0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0x214/0x310 arch/x86/entry/common.c:158
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
 entry_SYSCALL_64_fastpath+0x9e/0xa0

The buggy address belongs to the object at ffff8801d1db3420
 which belongs to the cache anon_vma_chain of size 64
The buggy address is located 8 bytes inside of
 64-byte region [ffff8801d1db3420, ffff8801d1db3460)
The buggy address belongs to the page:
page:ffffea0007476cc0 count:1 mapcount:0 mapping:ffff8801d1db3000 index:0xffff8801d1db3900
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d1db3000 ffff8801d1db3900 000000010000001e
raw: ffffea000755fea0 ffffea000710f560 ffff8801dad30500 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d1db3300: fb fb fb fb fb fb fb fb fc fc fc fc fb fb fb fb
 ffff8801d1db3380: fb fb fb fb fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8801d1db3400: fc fc fc fc fb fb fb fb fb fb fb fb fc fc fc fc
                                  ^
 ffff8801d1db3480: fb fb fb fb fb fb fb fb fc fc fc fc fb fb fb fb
 ffff8801d1db3500: fb fb fb fb fc fc fc fc fb fb fb fb fb fb fb fb
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