================================================================== 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:1696 [inline] BUG: KASAN: use-after-free in sk_dst_check+0x372/0x3a0 net/core/sock.c:513 Read of size 4 at addr ffff8801a6616e40 by task syz-executor4/1722 CPU: 1 PID: 1722 Comm: syz-executor4 Not tainted 4.9.128+ #41 ffff8801adce7690 ffffffff81af2469 ffffea0006998580 ffff8801a6616e40 0000000000000000 ffff8801a6616e40 ffff8801a6616e40 ffff8801adce76c8 ffffffff814e13cb ffff8801a6616e40 0000000000000004 0000000000000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] print_address_description+0x6c/0x234 mm/kasan/report.c:256 [] kasan_report_error mm/kasan/report.c:355 [inline] [] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412 [] __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:1696 [inline] [] sk_dst_check+0x372/0x3a0 net/core/sock.c:513 [] udp_sendmsg+0x107a/0x1c50 net/ipv4/udp.c:1010 [] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:770 [] sock_sendmsg_nosec net/socket.c:648 [inline] [] sock_sendmsg+0xbb/0x110 net/socket.c:658 [] ___sys_sendmsg+0x47a/0x840 net/socket.c:1982 [] __sys_sendmmsg+0x161/0x3d0 net/socket.c:2072 [] SYSC_sendmmsg net/socket.c:2103 [inline] [] SyS_sendmmsg+0x35/0x60 net/socket.c:2098 [] do_syscall_64+0x19f/0x480 arch/x86/entry/common.c:282 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 1722: 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.1+0x62/0xf0 mm/kasan/kasan.c:609 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:594 kasan_slab_alloc+0x12/0x20 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+0xb5/0x1a0 net/core/dst.c:210 ipv4_blackhole_route+0x30/0x700 net/ipv4/route.c:2407 make_blackhole net/xfrm/xfrm_policy.c:2186 [inline] xfrm_lookup_route+0xf5/0x140 net/xfrm/xfrm_policy.c:2356 ip_route_output_flow+0x90/0xa0 net/ipv4/route.c:2448 udp_sendmsg+0x13cd/0x1c50 net/ipv4/udp.c:1025 inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:770 sock_sendmsg_nosec net/socket.c:648 [inline] sock_sendmsg+0xbb/0x110 net/socket.c:658 ___sys_sendmsg+0x47a/0x840 net/socket.c:1982 __sys_sendmmsg+0x161/0x3d0 net/socket.c:2072 SYSC_sendmmsg net/socket.c:2103 [inline] SyS_sendmmsg+0x35/0x60 net/socket.c:2098 do_syscall_64+0x19f/0x480 arch/x86/entry/common.c:282 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 1682: 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+0xac/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+0x277/0x350 net/core/dst.c:270 dst_gc_task+0x1a9/0x510 net/core/dst.c:89 process_one_work+0x791/0x1470 kernel/workqueue.c:2092 worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226 kthread+0x26d/0x300 kernel/kthread.c:211 ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 The buggy address belongs to the object at ffff8801a6616dc0 which belongs to the cache ip_dst_cache of size 216 The buggy address is located 128 bytes inside of 216-byte region [ffff8801a6616dc0, ffff8801a6616e98) The buggy address belongs to the page: page:ffffea0006998580 count:1 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000080(slab) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801a6616d00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff8801a6616d80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff8801a6616e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801a6616e80: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801a6616f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== audit_printk_skb: 6 callbacks suppressed audit: type=1400 audit(2000000680.373:1590): avc: denied { create } for pid=1763 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0 audit: type=1400 audit(2000000680.443:1591): avc: denied { create } for pid=1757 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0