================================================================== BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] BUG: KASAN: use-after-free in atomic_fetch_add_unless include/linux/atomic.h:575 [inline] BUG: KASAN: use-after-free in atomic_add_unless include/linux/atomic.h:597 [inline] BUG: KASAN: use-after-free in dst_hold_safe include/net/dst.h:308 [inline] BUG: KASAN: use-after-free in ip6_hold_safe+0xa7/0x3a0 net/ipv6/route.c:1023 Read of size 4 at addr ffff88808ebad321 by task syz-executor.4/8796 CPU: 0 PID: 8796 Comm: syz-executor.4 Not tainted 5.0.0+ #5 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:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 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:100 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] atomic_fetch_add_unless include/linux/atomic.h:575 [inline] atomic_add_unless include/linux/atomic.h:597 [inline] dst_hold_safe include/net/dst.h:308 [inline] ip6_hold_safe+0xa7/0x3a0 net/ipv6/route.c:1023 rt6_get_pcpu_route net/ipv6/route.c:1243 [inline] ip6_pol_route+0x33d/0xf00 net/ipv6/route.c:1904 ip6_pol_route_input+0x65/0x80 net/ipv6/route.c:1923 fib6_rule_lookup+0x128/0x560 net/ipv6/fib6_rules.c:118 ip6_route_input_lookup+0xb7/0xd0 net/ipv6/route.c:1935 ip6_route_input+0x5e6/0x9e0 net/ipv6/route.c:2070 ip6_rcv_finish_core.isra.0+0x174/0x590 net/ipv6/ip6_input.c:63 ip6_rcv_finish+0x17d/0x320 net/ipv6/ip6_input.c:74 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:272 __netif_receive_skb_one_core+0x115/0x1a0 net/core/dev.c:4973 __netif_receive_skb+0x2c/0x1c0 net/core/dev.c:5083 netif_receive_skb_internal+0x117/0x660 net/core/dev.c:5186 netif_receive_skb+0x6e/0x5a0 net/core/dev.c:5261 tun_rx_batched.isra.0+0x4f7/0x840 drivers/net/tun.c:1562 tun_get_user+0x2964/0x3dd0 drivers/net/tun.c:1991 tun_chr_write_iter+0xbd/0x160 drivers/net/tun.c:2019 call_write_iter include/linux/fs.h:1869 [inline] do_iter_readv_writev+0x5e0/0x8e0 fs/read_write.c:680 do_iter_write fs/read_write.c:956 [inline] do_iter_write+0x184/0x610 fs/read_write.c:937 compat_writev+0x1f6/0x3a0 fs/read_write.c:1270 do_compat_writev+0xf5/0x1f0 fs/read_write.c:1291 __do_compat_sys_writev fs/read_write.c:1302 [inline] __se_compat_sys_writev fs/read_write.c:1298 [inline] __ia32_compat_sys_writev+0x74/0xb0 fs/read_write.c:1298 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7ffd869 Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f5df9054 EFLAGS: 00000292 ORIG_RAX: 0000000000000092 RAX: ffffffffffffffda RBX: 00000000000000f0 RCX: 00000000f5df90a4 RDX: 0000000000000001 RSI: 00000000200001c0 RDI: 00000000ffffffff RBP: 00000000f5df9168 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 0: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_kmalloc mm/kasan/common.c:495 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:468 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:503 slab_post_alloc_hook mm/slab.h:440 [inline] slab_alloc mm/slab.c:3388 [inline] kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3548 dst_alloc+0x10e/0x1d0 net/core/dst.c:105 ip6_dst_alloc+0x34/0xa0 net/ipv6/route.c:355 icmp6_dst_alloc+0x1a9/0x660 net/ipv6/route.c:2664 ndisc_send_skb+0xfc6/0x14a0 net/ipv6/ndisc.c:471 ndisc_send_rs+0x134/0x6d0 net/ipv6/ndisc.c:685 addrconf_rs_timer+0x30f/0x680 net/ipv6/addrconf.c:3841 call_timer_fn+0x190/0x720 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers kernel/time/timer.c:1681 [inline] __run_timers kernel/time/timer.c:1649 [inline] run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1694 __do_softirq+0x266/0x95a kernel/softirq.c:292 Freed by task 0: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:457 kasan_slab_free+0xe/0x10 mm/kasan/common.c:465 __cache_free mm/slab.c:3494 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3754 dst_destroy+0x2a0/0x3c0 net/core/dst.c:141 dst_destroy_rcu+0x16/0x19 net/core/dst.c:154 __rcu_reclaim kernel/rcu/rcu.h:240 [inline] rcu_do_batch kernel/rcu/tree.c:2452 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2773 [inline] rcu_process_callbacks+0x928/0x1390 kernel/rcu/tree.c:2754 __do_softirq+0x266/0x95a kernel/softirq.c:292 The buggy address belongs to the object at ffff88808ebad300 which belongs to the cache ip6_dst_cache of size 224 The buggy address is located 33 bytes inside of 224-byte region [ffff88808ebad300, ffff88808ebad3e0) The buggy address belongs to the page: page:ffffea00023aeb40 count:1 mapcount:0 mapping:ffff8882164736c0 index:0xffff88808ebada80 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea00025f1148 ffffea0002452948 ffff8882164736c0 raw: ffff88808ebada80 ffff88808ebad080 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808ebad200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88808ebad280: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc >ffff88808ebad300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808ebad380: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff88808ebad400: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ==================================================================