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BUG: KASAN: slab-out-of-bounds in erspan_build_header+0x3bf/0x3d0 net/ipv4/ip_gre.c:698
Read of size 2 at addr ffff8801d635528b by task syz-executor4/25262

CPU: 1 PID: 25262 Comm: syz-executor4 Not tainted 4.15.0-rc9+ #280
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
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:440
 erspan_build_header+0x3bf/0x3d0 net/ipv4/ip_gre.c:698
 erspan_xmit+0x3b8/0x13b0 net/ipv4/ip_gre.c:740
 __netdev_start_xmit include/linux/netdevice.h:4042 [inline]
 netdev_start_xmit include/linux/netdevice.h:4051 [inline]
 packet_direct_xmit+0x315/0x6b0 net/packet/af_packet.c:266
 packet_snd net/packet/af_packet.c:2943 [inline]
 packet_sendmsg+0x3aed/0x60b0 net/packet/af_packet.c:2968
 sock_sendmsg_nosec net/socket.c:638 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:648
 SYSC_sendto+0x361/0x5c0 net/socket.c:1729
 SyS_sendto+0x40/0x50 net/socket.c:1697
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x452f19
RSP: 002b:00007f85f20ecc58 EFLAGS: 00000212 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452f19
RDX: 0000000000000000 RSI: 0000000020003fd9 RDI: 0000000000000013
RBP: 000000000000059c R08: 0000000020008000 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f7740
R13: 00000000ffffffff R14: 00007f85f20ed6d4 R15: 0000000000000000

Allocated by task 1:
 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
 kmem_cache_zalloc include/linux/slab.h:678 [inline]
 __kernfs_new_node+0xe2/0x570 fs/kernfs/dir.c:633
 kernfs_new_node+0x80/0xe0 fs/kernfs/dir.c:679
 __kernfs_create_file+0x4b/0x320 fs/kernfs/file.c:989
 sysfs_add_file_mode_ns+0x220/0x510 fs/sysfs/file.c:307
 sysfs_add_file+0x4e/0x60 fs/sysfs/file.c:320
 sysfs_merge_group+0xef/0x210 fs/sysfs/group.c:295
 dpm_sysfs_add+0x126/0x1c0 drivers/base/power/sysfs.c:680
 device_add+0xc32/0x1650 drivers/base/core.c:1810
 input_register_device+0x636/0xe00 drivers/input/input.c:2135
 acpi_button_add+0x3e0/0x990 drivers/acpi/button.c:542
 acpi_device_probe+0xce/0x340 drivers/acpi/bus.c:879
 really_probe drivers/base/dd.c:424 [inline]
 driver_probe_device+0x71b/0xae0 drivers/base/dd.c:566
 __driver_attach+0x181/0x1c0 drivers/base/dd.c:800
 bus_for_each_dev+0x154/0x1e0 drivers/base/bus.c:313
 driver_attach+0x3d/0x50 drivers/base/dd.c:819
 bus_add_driver+0x466/0x620 drivers/base/bus.c:669
 driver_register+0x1bf/0x3c0 drivers/base/driver.c:168
 acpi_bus_register_driver+0xfd/0x150 drivers/acpi/bus.c:829
 acpi_button_driver_init+0x15/0x17 drivers/acpi/button.c:616
 do_one_initcall+0xad/0x357 init/main.c:832
 do_initcall_level init/main.c:898 [inline]
 do_initcalls init/main.c:906 [inline]
 do_basic_setup init/main.c:924 [inline]
 kernel_init_freeable+0x469/0x521 init/main.c:1072
 kernel_init+0x13/0x180 init/main.c:999
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:541

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8801d63551c0
 which belongs to the cache kernfs_node_cache of size 160
The buggy address is located 43 bytes to the right of
 160-byte region [ffff8801d63551c0, ffff8801d6355260)
The buggy address belongs to the page:
page:ffffea000758d540 count:1 mapcount:0 mapping:ffff8801d6355000 index:0xffff8801d6355fee
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d6355000 ffff8801d6355fee 0000000100000012
raw: ffffea000758d520 ffffea000758d5a0 ffff8801d9ea2dc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d6355180: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff8801d6355200: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
>ffff8801d6355280: fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00 00
                      ^
 ffff8801d6355300: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff8801d6355380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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