================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:232 [inline] BUG: KASAN: use-after-free in __in6_dev_get include/net/addrconf.h:309 [inline] BUG: KASAN: use-after-free in ip6_ignore_linkdown include/net/addrconf.h:400 [inline] BUG: KASAN: use-after-free in find_match+0xb39/0xc90 net/ipv6/route.c:749 Read of size 8 at addr ffff88805db8e320 by task ksoftirqd/0/9 CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.6.0-rc1-next-20200214-syzkaller #0 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+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:641 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 __read_once_size include/linux/compiler.h:232 [inline] __in6_dev_get include/net/addrconf.h:309 [inline] ip6_ignore_linkdown include/net/addrconf.h:400 [inline] find_match+0xb39/0xc90 net/ipv6/route.c:749 __find_rr_leaf+0x14e/0x750 net/ipv6/route.c:837 find_rr_leaf net/ipv6/route.c:858 [inline] rt6_select net/ipv6/route.c:902 [inline] fib6_table_lookup+0x697/0xdb0 net/ipv6/route.c:2170 ip6_pol_route+0x1f6/0xa70 net/ipv6/route.c:2206 ip6_pol_route_input+0x65/0x80 net/ipv6/route.c:2264 fib6_rule_lookup+0x133/0x7d0 net/ipv6/fib6_rules.c:114 ip6_route_input_lookup+0xb7/0xd0 net/ipv6/route.c:2276 ip6_route_input+0x5f0/0xa40 net/ipv6/route.c:2445 ip6_rcv_finish_core.isra.0+0x174/0x590 net/ipv6/ip6_input.c:63 ip6_rcv_finish+0x17a/0x310 net/ipv6/ip6_input.c:74 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:306 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:5198 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5312 process_backlog+0x226/0x780 net/core/dev.c:6144 napi_poll net/core/dev.c:6582 [inline] net_rx_action+0x508/0x1120 net/core/dev.c:6650 __do_softirq+0x262/0x98c kernel/softirq.c:292 run_ksoftirqd kernel/softirq.c:603 [inline] run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595 smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Allocated by task 29042: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:515 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] uevent_show+0x165/0x370 drivers/base/core.c:1516 dev_attr_show+0x50/0xa0 drivers/base/core.c:1225 sysfs_kf_seq_show+0x1fc/0x410 fs/sysfs/file.c:60 kernfs_seq_show+0x14f/0x1b0 fs/kernfs/file.c:167 seq_read+0x4ca/0x1170 fs/seq_file.c:229 kernfs_fop_read+0xed/0x590 fs/kernfs/file.c:251 __vfs_read+0x8a/0x110 fs/read_write.c:425 vfs_read+0x1f0/0x440 fs/read_write.c:461 ksys_read+0x14f/0x290 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x73/0xb0 fs/read_write.c:595 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 29042: save_stack+0x23/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x2c0 mm/slab.c:3757 uevent_show+0x2ca/0x370 drivers/base/core.c:1529 dev_attr_show+0x50/0xa0 drivers/base/core.c:1225 sysfs_kf_seq_show+0x1fc/0x410 fs/sysfs/file.c:60 kernfs_seq_show+0x14f/0x1b0 fs/kernfs/file.c:167 seq_read+0x4ca/0x1170 fs/seq_file.c:229 kernfs_fop_read+0xed/0x590 fs/kernfs/file.c:251 __vfs_read+0x8a/0x110 fs/read_write.c:425 vfs_read+0x1f0/0x440 fs/read_write.c:461 ksys_read+0x14f/0x290 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x73/0xb0 fs/read_write.c:595 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88805db8e000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 800 bytes inside of 4096-byte region [ffff88805db8e000, ffff88805db8f000) The buggy address belongs to the page: page:ffffea000176e380 refcount:1 mapcount:0 mapping:ffff8880aa402000 index:0x0 compound_mapcount: 0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea00011c3c08 ffffea000247c188 ffff8880aa402000 raw: 0000000000000000 ffff88805db8e000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88805db8e200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805db8e280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88805db8e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88805db8e380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805db8e400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================