================================================================== BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] BUG: KASAN: use-after-free in atomic_fetch_add_unless include/linux/atomic-fallback.h:1086 [inline] BUG: KASAN: use-after-free in atomic_add_unless include/linux/atomic-fallback.h:1111 [inline] BUG: KASAN: use-after-free in atomic_inc_not_zero include/linux/atomic-fallback.h:1127 [inline] BUG: KASAN: use-after-free in dst_hold_safe include/net/dst.h:297 [inline] BUG: KASAN: use-after-free in ip6_hold_safe+0xad/0x380 net/ipv6/route.c:1050 Read of size 4 at addr ffff88809eb5b330 by task syz-executor.2/31165 CPU: 1 PID: 31165 Comm: syz-executor.2 Not tainted 5.2.0-rc1+ #3 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+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 kasan_report+0x12/0x20 mm/kasan/common.c:614 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x123/0x190 mm/kasan/generic.c:191 kasan_check_read+0x11/0x20 mm/kasan/common.c:94 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] atomic_fetch_add_unless include/linux/atomic-fallback.h:1086 [inline] atomic_add_unless include/linux/atomic-fallback.h:1111 [inline] atomic_inc_not_zero include/linux/atomic-fallback.h:1127 [inline] dst_hold_safe include/net/dst.h:297 [inline] ip6_hold_safe+0xad/0x380 net/ipv6/route.c:1050 rt6_get_pcpu_route net/ipv6/route.c:1277 [inline] ip6_pol_route+0x336/0x1050 net/ipv6/route.c:2028 ip6_pol_route_input+0x65/0x80 net/ipv6/route.c:2047 __fib6_rule_action net/ipv6/fib6_rules.c:230 [inline] fib6_rule_action+0x49c/0xb40 net/ipv6/fib6_rules.c:261 fib_rules_lookup+0x34c/0xa90 net/core/fib_rules.c:304 fib6_rule_lookup+0x384/0x5a0 net/ipv6/fib6_rules.c:108 ip6_route_input_lookup+0xb7/0xd0 net/ipv6/route.c:2059 ip6_route_input+0x5e2/0x9e0 net/ipv6/route.c:2194 ip6_rcv_finish_core.isra.0+0x174/0x590 net/ipv6/ip6_input.c:67 ip6_rcv_finish+0x17a/0x310 net/ipv6/ip6_input.c:78 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:276 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:4990 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5104 netif_receive_skb_internal+0x117/0x5c0 net/core/dev.c:5207 napi_frags_finish net/core/dev.c:5774 [inline] napi_gro_frags+0xada/0xd10 net/core/dev.c:5848 tun_get_user+0x2f3c/0x3ff0 drivers/net/tun.c:1991 tun_chr_write_iter+0xbd/0x156 drivers/net/tun.c:2037 call_write_iter include/linux/fs.h:1872 [inline] do_iter_readv_writev+0x5f8/0x8f0 fs/read_write.c:693 do_iter_write fs/read_write.c:970 [inline] do_iter_write+0x184/0x610 fs/read_write.c:951 vfs_writev+0x1b3/0x2f0 fs/read_write.c:1015 do_writev+0x15b/0x330 fs/read_write.c:1058 __do_sys_writev fs/read_write.c:1131 [inline] __se_sys_writev fs/read_write.c:1128 [inline] __x64_sys_writev+0x75/0xb0 fs/read_write.c:1128 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459131 Code: 75 14 b8 14 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 b9 fb ff c3 48 83 ec 08 e8 fa 2c 00 00 48 89 04 24 b8 14 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 43 2d 00 00 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007f160f094ba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 000000000000004a RCX: 0000000000459131 RDX: 0000000000000001 RSI: 00007f160f094c00 RDI: 00000000000000f0 RBP: 000000000075c060 R08: 0000000000000000 R09: 0000000000000000 R10: 00007f160f0959d0 R11: 0000000000000293 R12: 00007f160f0956d4 R13: 00000000004c7d21 R14: 00000000004de160 R15: 00000000ffffffff Allocated by task 30545: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_kmalloc mm/kasan/common.c:489 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:497 slab_post_alloc_hook mm/slab.h:437 [inline] slab_alloc mm/slab.c:3326 [inline] kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3488 dst_alloc+0x10e/0x200 net/core/dst.c:93 ip6_dst_alloc+0x34/0xa0 net/ipv6/route.c:356 icmp6_dst_alloc+0x1a9/0x660 net/ipv6/route.c:2800 ndisc_send_skb+0xfc1/0x14a0 net/ipv6/ndisc.c:488 ndisc_send_rs+0x134/0x6d0 net/ipv6/ndisc.c:702 addrconf_rs_timer+0x30f/0x680 net/ipv6/addrconf.c:3880 call_timer_fn+0x193/0x720 kernel/time/timer.c:1322 expire_timers kernel/time/timer.c:1366 [inline] __run_timers kernel/time/timer.c:1685 [inline] __run_timers kernel/time/timer.c:1653 [inline] run_timer_softirq+0x66f/0x1740 kernel/time/timer.c:1698 __do_softirq+0x25c/0x94c kernel/softirq.c:293 Freed by task 9: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459 __cache_free mm/slab.c:3432 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3698 dst_destroy+0x29e/0x3c0 net/core/dst.c:129 dst_destroy_rcu+0x16/0x19 net/core/dst.c:142 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2092 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline] rcu_core+0xba5/0x1500 kernel/rcu/tree.c:2291 __do_softirq+0x25c/0x94c kernel/softirq.c:293 The buggy address belongs to the object at ffff88809eb5b300 which belongs to the cache ip6_dst_cache of size 224 The buggy address is located 48 bytes inside of 224-byte region [ffff88809eb5b300, ffff88809eb5b3e0) The buggy address belongs to the page: page:ffffea00027ad6c0 refcount:1 mapcount:0 mapping:ffff88809b307cc0 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea0002438988 ffffea00025a86c8 ffff88809b307cc0 raw: 0000000000000000 ffff88809eb5b080 000000010000000c 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809eb5b200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88809eb5b280: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc >ffff88809eb5b300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809eb5b380: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff88809eb5b400: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ==================================================================