================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:248 [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:1706 [inline] BUG: KASAN: use-after-free in sk_dst_check+0x347/0x380 net/core/sock.c:513 Read of size 4 at addr ffff8801508cf940 by task syz-executor.5/22647 CPU: 0 PID: 22647 Comm: syz-executor.5 Not tainted 4.9.186+ #10 ffff8801bab4f6c8 ffffffff81b5a0b1 0000000000000000 ffffea00054233c0 ffff8801508cf940 0000000000000004 ffffffff822c2d07 ffff8801bab4f700 ffffffff8150ab68 0000000000000000 ffff8801508cf940 ffff8801508cf940 Call Trace: [<00000000a8481923>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000a8481923>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<00000000e406efd1>] print_address_description+0x6f/0x23a mm/kasan/report.c:256 [<00000000c853f188>] kasan_report_error mm/kasan/report.c:355 [inline] [<00000000c853f188>] kasan_report mm/kasan/report.c:413 [inline] [<00000000c853f188>] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:397 [<00000000cb91697d>] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:433 [<000000003d49af4b>] __read_once_size include/linux/compiler.h:248 [inline] [<000000003d49af4b>] atomic_read arch/x86/include/asm/atomic.h:26 [inline] [<000000003d49af4b>] __atomic_add_unless arch/x86/include/asm/atomic.h:240 [inline] [<000000003d49af4b>] atomic_add_unless include/linux/atomic.h:506 [inline] [<000000003d49af4b>] sk_dst_get include/net/sock.h:1706 [inline] [<000000003d49af4b>] sk_dst_check+0x347/0x380 net/core/sock.c:513 [<00000000632da59e>] udp_sendmsg+0x10a6/0x1c60 net/ipv4/udp.c:1014 [<00000000472dba77>] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:766 [<0000000007bd0712>] sock_sendmsg_nosec net/socket.c:649 [inline] [<0000000007bd0712>] sock_sendmsg+0xbe/0x110 net/socket.c:659 [<000000005a6bb9e4>] ___sys_sendmsg+0x387/0x8b0 net/socket.c:1983 [<000000006ecdfae9>] __sys_sendmmsg+0x164/0x3d0 net/socket.c:2073 [<00000000f3c3b04d>] SYSC_sendmmsg net/socket.c:2104 [inline] [<00000000f3c3b04d>] SyS_sendmmsg+0x35/0x60 net/socket.c:2099 [<00000000710b1ed3>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<0000000000d83e65>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 22652: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:512 [inline] set_track mm/kasan/kasan.c:524 [inline] kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:616 kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:601 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:554 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:2442 make_blackhole net/xfrm/xfrm_policy.c:2214 [inline] xfrm_lookup_route net/xfrm/xfrm_policy.c:2387 [inline] xfrm_lookup_route+0xf4/0x140 net/xfrm/xfrm_policy.c:2378 ip_route_output_flow+0x93/0xa0 net/ipv4/route.c:2483 udp_sendmsg+0x1494/0x1c60 net/ipv4/udp.c:1029 inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:766 sock_sendmsg_nosec net/socket.c:649 [inline] sock_sendmsg+0xbe/0x110 net/socket.c:659 ___sys_sendmsg+0x387/0x8b0 net/socket.c:1983 __sys_sendmmsg+0x164/0x3d0 net/socket.c:2073 SYSC_sendmmsg net/socket.c:2104 [inline] SyS_sendmmsg+0x35/0x60 net/socket.c:2099 do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 16542: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:512 [inline] set_track mm/kasan/kasan.c:524 [inline] kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:589 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/0x1600 kernel/workqueue.c:2114 worker_thread+0x5df/0x11d0 kernel/workqueue.c:2251 kthread+0x278/0x310 kernel/kthread.c:211 ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375 The buggy address belongs to the object at ffff8801508cf8c0 which belongs to the cache ip_dst_cache of size 216 The buggy address is located 128 bytes inside of 216-byte region [ffff8801508cf8c0, ffff8801508cf998) The buggy address belongs to the page: page:ffffea00054233c0 count:1 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000200(slab) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801508cf800: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc ffff8801508cf880: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff8801508cf900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801508cf980: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801508cfa00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================