================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:243 [inline] BUG: KASAN: use-after-free in atomic_read arch/x86/include/asm/atomic.h:26 [inline] BUG: KASAN: use-after-free in __atomic_add_unless arch/x86/include/asm/atomic.h:240 [inline] BUG: KASAN: use-after-free in atomic_add_unless include/linux/atomic.h:506 [inline] BUG: KASAN: use-after-free in sk_dst_get include/net/sock.h:1700 [inline] BUG: KASAN: use-after-free in sk_dst_check+0x347/0x380 net/core/sock.c:513 Read of size 4 at addr ffff8801d0ed5940 by task syz-executor3/24728 CPU: 1 PID: 24728 Comm: syz-executor3 Not tainted 4.9.150+ #6 ffff8801d2537678 ffffffff81b47ee1 0000000000000000 ffffea000743b540 ffff8801d0ed5940 0000000000000004 ffffffff822ace07 ffff8801d25376b0 ffffffff815020b5 0000000000000000 ffff8801d0ed5940 ffff8801d0ed5940 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] print_address_description+0x6f/0x238 mm/kasan/report.c:256 [] kasan_report_error mm/kasan/report.c:355 [inline] [] kasan_report mm/kasan/report.c:412 [inline] [] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:397 [] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 [] __read_once_size include/linux/compiler.h:243 [inline] [] atomic_read arch/x86/include/asm/atomic.h:26 [inline] [] __atomic_add_unless arch/x86/include/asm/atomic.h:240 [inline] [] atomic_add_unless include/linux/atomic.h:506 [inline] [] sk_dst_get include/net/sock.h:1700 [inline] [] sk_dst_check+0x347/0x380 net/core/sock.c:513 [] ip6_sk_dst_lookup_flow+0xc6/0x580 net/ipv6/ip6_output.c:1117 [] udpv6_sendmsg+0x18c2/0x2430 net/ipv6/udp.c:1222 [] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:770 [] sock_sendmsg_nosec net/socket.c:648 [inline] [] sock_sendmsg+0xbe/0x110 net/socket.c:658 [] ___sys_sendmsg+0x387/0x8b0 net/socket.c:1982 [] __sys_sendmmsg+0x164/0x3d0 net/socket.c:2072 [] SYSC_sendmmsg net/socket.c:2103 [inline] [] SyS_sendmmsg+0x35/0x60 net/socket.c:2098 [] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 24728: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:505 [inline] set_track mm/kasan/kasan.c:517 [inline] kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:609 kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:594 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:547 slab_post_alloc_hook mm/slab.h:417 [inline] slab_alloc_node mm/slub.c:2715 [inline] slab_alloc mm/slub.c:2723 [inline] kmem_cache_alloc+0xd5/0x2b0 mm/slub.c:2728 dst_alloc+0xf3/0x1b0 net/core/dst.c:210 ipv4_blackhole_route+0x30/0x720 net/ipv4/route.c:2407 make_blackhole net/xfrm/xfrm_policy.c:2211 [inline] xfrm_lookup_route net/xfrm/xfrm_policy.c:2384 [inline] xfrm_lookup_route+0xf4/0x140 net/xfrm/xfrm_policy.c:2375 ip_route_output_flow+0x93/0xa0 net/ipv4/route.c:2448 ip_route_connect include/net/route.h:297 [inline] __ip4_datagram_connect+0x71f/0x1050 net/ipv4/datagram.c:51 __ip6_datagram_connect+0xa60/0xe10 net/ipv6/datagram.c:196 ip6_datagram_connect+0x30/0x50 net/ipv6/datagram.c:268 inet_dgram_connect+0x119/0x1f0 net/ipv4/af_inet.c:549 SYSC_connect net/socket.c:1575 [inline] SyS_connect+0x1a5/0x2e0 net/socket.c:1556 do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 20768: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:505 [inline] set_track mm/kasan/kasan.c:517 [inline] kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:582 slab_free_hook mm/slub.c:1355 [inline] slab_free_freelist_hook mm/slub.c:1377 [inline] slab_free mm/slub.c:2958 [inline] kmem_cache_free+0xbe/0x310 mm/slub.c:2980 dst_destroy+0x275/0x350 net/core/dst.c:270 dst_gc_task+0x1b2/0x520 net/core/dst.c:89 process_one_work+0x88b/0x15c0 kernel/workqueue.c:2092 worker_thread+0x5df/0x11d0 kernel/workqueue.c:2226 kthread+0x278/0x310 kernel/kthread.c:211 ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 The buggy address belongs to the object at ffff8801d0ed58c0 which belongs to the cache ip_dst_cache of size 216 The buggy address is located 128 bytes inside of 216-byte region [ffff8801d0ed58c0, ffff8801d0ed5998) The buggy address belongs to the page: page:ffffea000743b540 count:1 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000080(slab) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d0ed5800: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff8801d0ed5880: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff8801d0ed5900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801d0ed5980: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801d0ed5a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================