================================================================== 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 ffff88019ad7b2c4 by task syz-executor0/12829 CPU: 1 PID: 12829 Comm: syz-executor0 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:_vm_normal_page+0x18b/0x320 mm/memory.c:892 Code: 00 00 fc ff df 49 c7 04 04 00 00 00 00 48 89 d8 48 8b 4d d0 65 48 33 0c 25 28 00 00 00 0f 85 65 01 00 00 48 83 c4 70 5b 41 5c <41> 5d 41 5e 41 5f 5d c3 e8 88 00 d1 ff 49 8d be 90 00 00 00 48 b8 RSP: 0018:ffff88019a96eb98 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: ffffea00071b2800 RBX: ffff8801af7d5178 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff81ab16dc RDI: 0000000000000006 RBP: ffff88019a96ebb0 R08: ffff8801d823e300 R09: fffff94000e3c8be R10: fffff94000e3c8be R11: ffffea00071e45f3 R12: 80000001c6ca0007 R13: ffff88019a96eb88 R14: ffff8801d72e6840 R15: 000000000021ffff zap_pte_range mm/memory.c:1306 [inline] zap_pmd_range mm/memory.c:1437 [inline] zap_pud_range mm/memory.c:1466 [inline] zap_p4d_range mm/memory.c:1487 [inline] unmap_page_range+0xa6c/0x2220 mm/memory.c:1508 unmap_single_vma+0x1a0/0x310 mm/memory.c:1553 unmap_vmas+0x120/0x1f0 mm/memory.c:1583 exit_mmap+0x2c2/0x5b0 mm/mmap.c:3094 __mmput kernel/fork.c:993 [inline] mmput+0x265/0x620 kernel/fork.c:1014 exit_mm kernel/exit.c:544 [inline] do_exit+0xea9/0x2750 kernel/exit.c:852 do_group_exit+0x177/0x440 kernel/exit.c:968 get_signal+0x88e/0x1970 kernel/signal.c:2468 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e0/0x370 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x456a09 Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fe4b02aacf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 0000000000930148 RCX: 0000000000456a09 RDX: 0000000000000020 RSI: 0000000000000001 RDI: 000000000093014c RBP: 0000000000930140 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000093014c R13: 00007ffeaba05d4f R14: 00007fe4b02ab9c0 R15: 0000000000000001 Allocated by task 10478: 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 12829: 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 ffff88019ad7b280 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 68 bytes inside of 96-byte region [ffff88019ad7b280, ffff88019ad7b2e0) The buggy address belongs to the page: page:ffffea00066b5ec0 count:1 mapcount:0 mapping:ffff8801dac004c0 index:0xffff88019ad7b980 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0006fccd88 ffffea0007281d08 ffff8801dac004c0 raw: ffff88019ad7b980 ffff88019ad7b000 0000000100000015 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88019ad7b180: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff88019ad7b200: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff88019ad7b280: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff88019ad7b300: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff88019ad7b380: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ==================================================================