================================================================== BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] BUG: KASAN: use-after-free in refcount_sub_and_test+0x9a/0x350 lib/refcount.c:179 Read of size 4 at addr ffff8801c346f5c4 by task syz-executor1/4388 CPU: 1 PID: 4388 Comm: syz-executor1 Not tainted 4.18.0-rc7+ #35 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] refcount_sub_and_test+0x9a/0x350 lib/refcount.c:179 refcount_dec_and_test+0x1a/0x20 lib/refcount.c:212 fib6_metrics_release+0x4f/0x90 net/ipv6/ip6_fib.c:178 fib6_drop_pcpu_from net/ipv6/ip6_fib.c:899 [inline] fib6_purge_rt+0x5ec/0x7f0 net/ipv6/ip6_fib.c:934 fib6_del_route net/ipv6/ip6_fib.c:1784 [inline] fib6_del+0xc11/0x1310 net/ipv6/ip6_fib.c:1815 fib6_clean_node+0x3ee/0x5e0 net/ipv6/ip6_fib.c:1976 fib6_walk_continue+0x4b1/0x8e0 net/ipv6/ip6_fib.c:1899 fib6_walk+0x95/0xf0 net/ipv6/ip6_fib.c:1947 fib6_clean_tree+0x1ea/0x360 net/ipv6/ip6_fib.c:2024 __fib6_clean_all+0x21c/0x420 net/ipv6/ip6_fib.c:2040 fib6_clean_all net/ipv6/ip6_fib.c:2051 [inline] fib6_run_gc+0x182/0x3d0 net/ipv6/ip6_fib.c:2107 fib6_gc_timer_cb+0x20/0x30 net/ipv6/ip6_fib.c:2124 call_timer_fn+0x242/0x970 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers+0x7a6/0xc70 kernel/time/timer.c:1666 run_timer_softirq+0x4c/0x70 kernel/time/timer.c:1692 __do_softirq+0x2e8/0xb17 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:372 [inline] irq_exit+0x1d4/0x210 kernel/softirq.c:412 exiting_irq arch/x86/include/asm/apic.h:527 [inline] smp_apic_timer_interrupt+0x186/0x730 arch/x86/kernel/apic/apic.c:1055 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:783 [inline] RIP: 0010:kfree+0x124/0x260 mm/slab.c:3814 Code: 1f 44 00 00 e8 0d 53 a4 ff 5b 41 5c 41 5d 41 5e 5d c3 e8 4f ea a4 ff 48 83 3d 8f e6 37 06 00 0f 84 25 01 00 00 4c 89 e7 57 9d <0f> 1f 44 00 00 5b 41 5c 41 5d 41 5e 5d c3 4c 89 f2 48 89 de 4c 89 RSP: 0018:ffff8801a6217938 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: ffff8801d894a100 RCX: 1ffff10034d0354b RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000286 RBP: ffff8801a6217958 R08: ffff8801a681aa38 R09: 0000000000000006 R10: ffff8801a681a200 R11: 0000000000000000 R12: 0000000000000286 R13: ffff8801dac001c0 R14: ffffffff81a57181 R15: dffffc0000000000 kvfree+0x61/0x70 mm/util.c:442 __vunmap+0x326/0x460 mm/vmalloc.c:1529 vfree+0x68/0x100 mm/vmalloc.c:1593 copy_entries_to_user net/ipv4/netfilter/ip_tables.c:870 [inline] get_entries net/ipv4/netfilter/ip_tables.c:1027 [inline] do_ipt_get_ctl+0xa1f/0xc00 net/ipv4/netfilter/ip_tables.c:1703 nf_sockopt net/netfilter/nf_sockopt.c:104 [inline] nf_getsockopt+0x80/0xe0 net/netfilter/nf_sockopt.c:122 ip_getsockopt+0x1fb/0x2b0 net/ipv4/ip_sockglue.c:1577 tcp_getsockopt+0x93/0xe0 net/ipv4/tcp.c:3550 sock_common_getsockopt+0x9a/0xe0 net/core/sock.c:2999 __sys_getsockopt+0x1ad/0x390 net/socket.c:1949 __do_sys_getsockopt net/socket.c:1960 [inline] __se_sys_getsockopt net/socket.c:1957 [inline] __x64_sys_getsockopt+0xbe/0x150 net/socket.c:1957 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4594fa Code: b8 34 01 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd 89 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 37 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 da 89 fb ff c3 66 0f 1f 84 00 00 00 00 00 RSP: 002b:00007fff26a5fb78 EFLAGS: 00000202 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 00007fff26a5fba0 RCX: 00000000004594fa RDX: 0000000000000041 RSI: 0000000000000000 RDI: 0000000000000013 RBP: 0000000000709f20 R08: 00007fff26a5fb9c R09: 0000000000004000 R10: 00007fff26a5fca0 R11: 0000000000000202 R12: 0000000000000013 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000708420 Allocated by task 4779: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620 kmalloc include/linux/slab.h:513 [inline] kzalloc include/linux/slab.h:707 [inline] fib6_metric_set+0x163/0x2c0 net/ipv6/ip6_fib.c:645 fib6_add_rt2node+0xe36/0x27f0 net/ipv6/ip6_fib.c:1000 fib6_add+0xaae/0x14d0 net/ipv6/ip6_fib.c:1308 __ip6_ins_rt+0x54/0x80 net/ipv6/route.c:1163 ip6_route_add+0x6d/0xc0 net/ipv6/route.c:3171 addrconf_prefix_route.isra.48+0x51d/0x720 net/ipv6/addrconf.c:2347 inet6_addr_modify net/ipv6/addrconf.c:4627 [inline] inet6_rtm_newaddr+0x112e/0x1b50 net/ipv6/addrconf.c:4743 rtnetlink_rcv_msg+0x46e/0xc30 net/core/rtnetlink.c:4665 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2453 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4683 netlink_unicast_kernel net/netlink/af_netlink.c:1315 [inline] netlink_unicast+0x5a0/0x760 net/netlink/af_netlink.c:1341 netlink_sendmsg+0xa18/0xfd0 net/netlink/af_netlink.c:1906 sock_sendmsg_nosec net/socket.c:642 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:652 ___sys_sendmsg+0x7fd/0x930 net/socket.c:2126 __sys_sendmsg+0x11d/0x290 net/socket.c:2164 __do_sys_sendmsg net/socket.c:2173 [inline] __se_sys_sendmsg net/socket.c:2171 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2171 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 4388: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xd9/0x260 mm/slab.c:3813 fib6_metrics_release+0x77/0x90 net/ipv6/ip6_fib.c:179 fib6_drop_pcpu_from net/ipv6/ip6_fib.c:899 [inline] fib6_purge_rt+0x5ec/0x7f0 net/ipv6/ip6_fib.c:934 fib6_del_route net/ipv6/ip6_fib.c:1784 [inline] fib6_del+0xc11/0x1310 net/ipv6/ip6_fib.c:1815 fib6_clean_node+0x3ee/0x5e0 net/ipv6/ip6_fib.c:1976 fib6_walk_continue+0x4b1/0x8e0 net/ipv6/ip6_fib.c:1899 fib6_walk+0x95/0xf0 net/ipv6/ip6_fib.c:1947 fib6_clean_tree+0x1ea/0x360 net/ipv6/ip6_fib.c:2024 __fib6_clean_all+0x21c/0x420 net/ipv6/ip6_fib.c:2040 fib6_clean_all net/ipv6/ip6_fib.c:2051 [inline] fib6_run_gc+0x182/0x3d0 net/ipv6/ip6_fib.c:2107 fib6_gc_timer_cb+0x20/0x30 net/ipv6/ip6_fib.c:2124 call_timer_fn+0x242/0x970 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers+0x7a6/0xc70 kernel/time/timer.c:1666 run_timer_softirq+0x4c/0x70 kernel/time/timer.c:1692 __do_softirq+0x2e8/0xb17 kernel/softirq.c:292 The buggy address belongs to the object at ffff8801c346f580 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 68 bytes inside of 96-byte region [ffff8801c346f580, ffff8801c346f5e0) The buggy address belongs to the page: page:ffffea00070d1bc0 count:1 mapcount:0 mapping:ffff8801dac004c0 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea00068c8908 ffffea0007604ec8 ffff8801dac004c0 raw: 0000000000000000 ffff8801c346f000 0000000100000020 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c346f480: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8801c346f500: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc >ffff8801c346f580: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff8801c346f600: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8801c346f680: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc ==================================================================