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SubjectKASAN: slab-out-of-bounds Write in queue_stack_map_push_elem

syzbot found the following crash on:

HEAD commit: e195ca6cb6f2 Merge branch 'for-linus' of git://git.kernel...
git tree: upstream
console output:
kernel config:
dashboard link:
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:
C reproducer:

IMPORTANT: if you fix the bug, please add the following tag to the commit:

BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:352 [inline]
BUG: KASAN: slab-out-of-bounds in queue_stack_map_push_elem+0x185/0x290
Write of size 262146 at addr ffff8881cce14448 by task syz-executor005/6050

CPU: 1 PID: 6050 Comm: syz-executor005 Not tainted 4.20.0-rc3+ #348
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+0x244/0x39d lib/dump_stack.c:113
print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.8+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
memcpy+0x37/0x50 mm/kasan/kasan.c:303
memcpy include/linux/string.h:352 [inline]
queue_stack_map_push_elem+0x185/0x290 kernel/bpf/queue_stack_maps.c:230
map_update_elem+0x605/0xf60 kernel/bpf/syscall.c:865
__do_sys_bpf kernel/bpf/syscall.c:2495 [inline]
__se_sys_bpf kernel/bpf/syscall.c:2466 [inline]
__x64_sys_bpf+0x32d/0x520 kernel/bpf/syscall.c:2466
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
RIP: 0033:0x4400e9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc7a0f28d8 EFLAGS: 00000213 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400e9
RDX: 0000000000000020 RSI: 0000000020000040 RDI: 0000000000000002
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401970
R13: 0000000000401a00 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6050:
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
__do_kmalloc_node mm/slab.c:3684 [inline]
__kmalloc_node+0x50/0x70 mm/slab.c:3691
kmalloc_node include/linux/slab.h:589 [inline]
bpf_map_area_alloc+0x3f/0x90 kernel/bpf/syscall.c:147
queue_stack_map_alloc+0x192/0x290 kernel/bpf/queue_stack_maps.c:84
find_and_alloc_map kernel/bpf/syscall.c:129 [inline]
map_create+0x3bd/0x1110 kernel/bpf/syscall.c:509
__do_sys_bpf kernel/bpf/syscall.c:2489 [inline]
__se_sys_bpf kernel/bpf/syscall.c:2466 [inline]
__x64_sys_bpf+0x303/0x520 kernel/bpf/syscall.c:2466
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290

Freed by task 3716:
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]
kfree+0xcf/0x230 mm/slab.c:3817
skb_free_head+0x99/0xc0 net/core/skbuff.c:550
skb_release_data+0x70c/0x9a0 net/core/skbuff.c:570
skb_release_all+0x4a/0x60 net/core/skbuff.c:627
__kfree_skb net/core/skbuff.c:641 [inline]
consume_skb+0x1ae/0x570 net/core/skbuff.c:701
skb_free_datagram+0x1a/0xf0 net/core/datagram.c:329
unix_dgram_recvmsg+0xd6d/0x1b10 net/unix/af_unix.c:2181
sock_recvmsg_nosec net/socket.c:794 [inline]
sock_recvmsg+0xd0/0x110 net/socket.c:801
__sys_recvfrom+0x311/0x5d0 net/socket.c:1845
__do_sys_recvfrom net/socket.c:1863 [inline]
__se_sys_recvfrom net/socket.c:1859 [inline]
__x64_sys_recvfrom+0xe1/0x1a0 net/socket.c:1859
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290

The buggy address belongs to the object at ffff8881cce14300
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 328 bytes inside of
512-byte region [ffff8881cce14300, ffff8881cce14500)
The buggy address belongs to the page:
page:ffffea0007338500 count:1 mapcount:0 mapping:ffff8881da800940
flags: 0x2fffc0000000200(slab)
raw: 02fffc0000000200 ffffea0006e31bc8 ffffea00071b4608 ffff8881da800940
raw: ffff8881cce14580 ffff8881cce14080 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881cce14380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881cce14400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffff8881cce14480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881cce14500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881cce14580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

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