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BUG: KASAN: use-after-free in sctp_association_free+0x7b7/0x930 net/sctp/associola.c:333
Read of size 8 at addr ffff8800699b4560 by task syzkaller481386/2993

CPU: 2 PID: 2993 Comm: syzkaller481386 Not tainted 4.14.0-rc5-next-20171018+ #8
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 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_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 sctp_association_free+0x7b7/0x930 net/sctp/associola.c:333
 sctp_sendmsg+0x1845/0x32b0 net/sctp/socket.c:2019
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
 sock_sendmsg_nosec net/socket.c:632 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:642
 SYSC_sendto+0x352/0x5a0 net/socket.c:1749
 SyS_sendto+0x40/0x50 net/socket.c:1717
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x43c309
RSP: 002b:00007f2275054db8 EFLAGS: 00000206 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043c309
RDX: 0000000000000002 RSI: 0000000020925000 RDI: 0000000000000003
RBP: 0000000000000082 R08: 00000000209e1000 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f22750559c0 R15: 00007f2275055700

Allocated by task 2993:
 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
 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3614
 kmalloc include/linux/slab.h:502 [inline]
 kzalloc include/linux/slab.h:691 [inline]
 sctp_association_new+0x114/0x21e0 net/sctp/associola.c:309
 sctp_sendmsg+0x1c89/0x32b0 net/sctp/socket.c:1839
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
 sock_sendmsg_nosec net/socket.c:632 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:642
 SYSC_sendto+0x352/0x5a0 net/socket.c:1749
 SyS_sendto+0x40/0x50 net/socket.c:1717
 entry_SYSCALL_64_fastpath+0x1f/0xbe

Freed by task 2993:
 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:3492 [inline]
 kfree+0xca/0x250 mm/slab.c:3807
 sctp_association_destroy net/sctp/associola.c:435 [inline]
 sctp_association_put+0x21c/0x2f0 net/sctp/associola.c:884
 sctp_wait_for_sndbuf+0x5e3/0x7c0 net/sctp/socket.c:7999
 sctp_sendmsg+0x2906/0x32b0 net/sctp/socket.c:1943
 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
 sock_sendmsg_nosec net/socket.c:632 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:642
 SYSC_sendto+0x352/0x5a0 net/socket.c:1749
 SyS_sendto+0x40/0x50 net/socket.c:1717
 entry_SYSCALL_64_fastpath+0x1f/0xbe

The buggy address belongs to the object at ffff8800699b4540
 which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 32 bytes inside of
 4096-byte region [ffff8800699b4540, ffff8800699b5540)
The buggy address belongs to the page:
page:ffffea0001a66d00 count:1 mapcount:0 mapping:ffff8800699b4540 index:0x0 compound_mapcount: 0
flags: 0x500000000008100(slab|head)
raw: 0500000000008100 ffff8800699b4540 0000000000000000 0000000100000001
raw: ffffea0001a26020 ffffea0001a2d8a0 ffff88003e800dc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8800699b4400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8800699b4480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8800699b4500: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                       ^
 ffff8800699b4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8800699b4600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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