Hello, syzbot found the following crash on: HEAD commit: ba6069759381 Merge tag 'mmc-v5.0-rc2' of git://git.kernel... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17b342c4c00000 kernel config: https://syzkaller.appspot.com/x/.config?x=505743eba4e4f68 dashboard link: https://syzkaller.appspot.com/bug?extid=bc5ab0af2dbf3b0ae897 compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+bc5ab0af2dbf3b0ae897 at syzkaller.appspotmail.com bridge0: port 2(bridge_slave_1) entered blocking state bridge0: port 2(bridge_slave_1) entered forwarding state bridge0: port 1(bridge_slave_0) entered blocking state bridge0: port 1(bridge_slave_0) entered forwarding state =================================================================BUG: KASAN: use-after-free in memcmp+0xb3/0xc0 lib/string.c:862 Read of size 1 at addr ffff88809f1efe70 by task syz-executor1/8111 CPU: 0 PID: 8111 Comm: syz-executor1 Not tainted 5.0.0-rc3+ #43 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 8021q: adding VLAN 0 to HW filter on device bond0 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:132 memcmp+0xb3/0xc0 lib/string.c:862 memcmp include/linux/string.h:393 [inline] rhashtable_compare include/linux/rhashtable.h:473 [inline] __rhashtable_lookup include/linux/rhashtable.h:498 [inline] rhashtable_lookup include/linux/rhashtable.h:534 [inline] br_mdb_ip_get+0x694/0xe30 net/bridge/br_multicast.c:97 IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready br_multicast_new_group+0x77/0x200 net/bridge/br_multicast.c:467 IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready 8021q: adding VLAN 0 to HW filter on device team0 br_multicast_add_group+0x4ce/0x7d0 net/bridge/br_multicast.c:552 br_ip6_multicast_add_group net/bridge/br_multicast.c:626 [inline] br_ip6_multicast_mld2_report net/bridge/br_multicast.c:1043 [inline] br_multicast_ipv6_rcv net/bridge/br_multicast.c:1667 [inline] br_multicast_rcv+0x24aa/0x4270 net/bridge/br_multicast.c:1705 IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready br_dev_xmit+0x7f4/0x1780 net/bridge/br_device.c:93 8021q: adding VLAN 0 to HW filter on device batadv0 __netdev_start_xmit include/linux/netdevice.h:4382 [inline] netdev_start_xmit include/linux/netdevice.h:4391 [inline] xmit_one net/core/dev.c:3278 [inline] dev_hard_start_xmit+0x261/0xc70 net/core/dev.c:3294 __dev_queue_xmit+0x2f8a/0x3a60 net/core/dev.c:3864 dev_queue_xmit+0x18/0x20 net/core/dev.c:3897 neigh_hh_output include/net/neighbour.h:498 [inline] neigh_output include/net/neighbour.h:506 [inline] ip6_finish_output2+0x141a/0x28e0 net/ipv6/ip6_output.c:120 ip6_finish_output+0x577/0xc30 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x23c/0xa00 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] mld_sendpack+0xa44/0xfd0 net/ipv6/mcast.c:1683 mld_send_cr net/ipv6/mcast.c:1979 [inline] mld_ifc_timer_expire+0x449/0x8a0 net/ipv6/mcast.c:2478 call_timer_fn+0x254/0x900 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers+0x6fc/0xd50 kernel/time/timer.c:1681 run_timer_softirq+0x52/0xb0 kernel/time/timer.c:1694 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1b7/0x760 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 </IRQ> RIP: 0010:kasan_check_read+0x0/0x20 mm/kasan/common.c:99 Code: ef e9 14 eb ff ff 48 8b 73 58 89 c2 48 c7 c7 f0 c2 3c 89 f7 da e8 54 69 a2 ff e9 c4 f5 ff ff 90 90 90 90 90 90 90 90 90 90 90 <55> 89 f6 31 d2 48 89 e5 48 8b 4d 08 e8 ff 23 00 00 5d c3 0f 1f 00 IPVS: ftp: loaded support on port[0] = 21 RSP: 0018:ffff88809e937428 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000000 RBX: ffffffff8a318400 RCX: ffffffff8162f642 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff8a318400 RBP: ffff88809e937530 R08: 1ffffffff1463080 R09: fffffbfff1463081 R10: fffffbfff1463080 R11: ffffffff8a318407 R12: ffff88809ac4c600 R13: ffff88809e937508 R14: dffffc0000000000 R15: ffffed1013d26e91 mutex_optimistic_spin kernel/locking/mutex.c:646 [inline] __mutex_lock_common kernel/locking/mutex.c:928 [inline] __mutex_lock+0x377/0x1670 kernel/locking/mutex.c:1072 IPVS: ftp: loaded support on port[0] = 21 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 rtnl_lock net/core/rtnetlink.c:77 [inline] rtnetlink_rcv_msg+0x425/0xc30 net/core/rtnetlink.c:5127 netlink_rcv_skb+0x17d/0x410 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5148 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] netlink_unicast+0x574/0x770 net/netlink/af_netlink.c:1336 netlink_sendmsg+0xa05/0xf90 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 __sys_sendto+0x387/0x5f0 net/socket.c:1788 __do_sys_sendto net/socket.c:1800 [inline] __se_sys_sendto net/socket.c:1796 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1796 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411fc3 Code: ff 0f 83 40 18 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 83 3d cd 42 64 00 00 75 17 49 89 ca b8 2c 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 11 18 00 00 c3 48 83 ec 08 e8 87 fa ff ff RSP: 002b:0000000000a4fb28 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000411fc3 RDX: 000000000000006c RSI: 0000000000a50070 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000a4fb30 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000a4fef0 R13: 0000000000a4fbb8 R14: 0000000000a4fc80 R15: 00000000004bcf8a Allocated by task 8111: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_kmalloc mm/kasan/common.c:496 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3609 kmalloc include/linux/slab.h:545 [inline] kzalloc include/linux/slab.h:740 [inline] br_multicast_new_group.part.0+0xdc/0x1a40 net/bridge/br_multicast.c:476 br_multicast_new_group+0x19d/0x200 net/bridge/br_multicast.c:471 br_multicast_add_group+0x4ce/0x7d0 net/bridge/br_multicast.c:552 br_ip6_multicast_add_group net/bridge/br_multicast.c:626 [inline] br_ip6_multicast_mld2_report net/bridge/br_multicast.c:1043 [inline] br_multicast_ipv6_rcv net/bridge/br_multicast.c:1667 [inline] br_multicast_rcv+0x24aa/0x4270 net/bridge/br_multicast.c:1705 br_dev_xmit+0x7f4/0x1780 net/bridge/br_device.c:93 __netdev_start_xmit include/linux/netdevice.h:4382 [inline] netdev_start_xmit include/linux/netdevice.h:4391 [inline] xmit_one net/core/dev.c:3278 [inline] dev_hard_start_xmit+0x261/0xc70 net/core/dev.c:3294 __dev_queue_xmit+0x2f8a/0x3a60 net/core/dev.c:3864 dev_queue_xmit+0x18/0x20 net/core/dev.c:3897 neigh_resolve_output net/core/neighbour.c:1476 [inline] neigh_resolve_output+0x6a0/0xb30 net/core/neighbour.c:1456 neigh_output include/net/neighbour.h:508 [inline] ip6_finish_output2+0xc56/0x28e0 net/ipv6/ip6_output.c:120 ip6_finish_output+0x577/0xc30 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x23c/0xa00 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] mld_sendpack+0xa44/0xfd0 net/ipv6/mcast.c:1683 mld_send_cr net/ipv6/mcast.c:1979 [inline] mld_ifc_timer_expire+0x449/0x8a0 net/ipv6/mcast.c:2478 call_timer_fn+0x254/0x900 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers+0x6fc/0xd50 kernel/time/timer.c:1681 run_timer_softirq+0x52/0xb0 kernel/time/timer.c:1694 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 Freed by task 8111: 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:458 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466 __cache_free mm/slab.c:3487 [inline] kfree+0xcf/0x230 mm/slab.c:3806 br_multicast_new_group.part.0+0x1489/0x1a40 net/bridge/br_multicast.c:486 br_multicast_new_group+0x19d/0x200 net/bridge/br_multicast.c:471 br_multicast_add_group+0x4ce/0x7d0 net/bridge/br_multicast.c:552 br_ip6_multicast_add_group net/bridge/br_multicast.c:626 [inline] br_ip6_multicast_mld2_report net/bridge/br_multicast.c:1043 [inline] br_multicast_ipv6_rcv net/bridge/br_multicast.c:1667 [inline] br_multicast_rcv+0x24aa/0x4270 net/bridge/br_multicast.c:1705 br_dev_xmit+0x7f4/0x1780 net/bridge/br_device.c:93 __netdev_start_xmit include/linux/netdevice.h:4382 [inline] netdev_start_xmit include/linux/netdevice.h:4391 [inline] xmit_one net/core/dev.c:3278 [inline] dev_hard_start_xmit+0x261/0xc70 net/core/dev.c:3294 __dev_queue_xmit+0x2f8a/0x3a60 net/core/dev.c:3864 dev_queue_xmit+0x18/0x20 net/core/dev.c:3897 neigh_resolve_output net/core/neighbour.c:1476 [inline] neigh_resolve_output+0x6a0/0xb30 net/core/neighbour.c:1456 neigh_output include/net/neighbour.h:508 [inline] ip6_finish_output2+0xc56/0x28e0 net/ipv6/ip6_output.c:120 ip6_finish_output+0x577/0xc30 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip6_output+0x23c/0xa00 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] mld_sendpack+0xa44/0xfd0 net/ipv6/mcast.c:1683 mld_send_cr net/ipv6/mcast.c:1979 [inline] mld_ifc_timer_expire+0x449/0x8a0 net/ipv6/mcast.c:2478 call_timer_fn+0x254/0x900 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers+0x6fc/0xd50 kernel/time/timer.c:1681 run_timer_softirq+0x52/0xb0 kernel/time/timer.c:1694 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 The buggy address belongs to the object at ffff88809f1efe00 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 112 bytes inside of 192-byte region [ffff88809f1efe00, ffff88809f1efec0) The buggy address belongs to the page: page:ffffea00027c7bc0 count:1 mapcount:0 mapping:ffff88812c3f0040 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea00027df108 ffffea00027c7c48 ffff88812c3f0040 raw: 0000000000000000 ffff88809f1ef000 0000000100000010 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809f1efd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88809f1efd80: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc> ffff88809f1efe00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb^ ffff88809f1efe80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88809f1eff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================= --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller at googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot.
Nikolay Aleksandrov
2019-Jan-27 21:34 UTC
[Bridge] KASAN: use-after-free Read in br_mdb_ip_get
On 27/01/2019 22:26, syzbot wrote:> Hello, > > syzbot found the following crash on: > > HEAD commit:??? ba6069759381 Merge tag 'mmc-v5.0-rc2' of git://git.kernel... > git tree:?????? upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=17b342c4c00000 > kernel config:? https://syzkaller.appspot.com/x/.config?x=505743eba4e4f68 > dashboard link: https://syzkaller.appspot.com/bug?extid=bc5ab0af2dbf3b0ae897 > compiler:?????? gcc (GCC) 9.0.0 20181231 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+bc5ab0af2dbf3b0ae897 at syzkaller.appspotmail.com > > bridge0: port 2(bridge_slave_1) entered blocking state > bridge0: port 2(bridge_slave_1) entered forwarding state > bridge0: port 1(bridge_slave_0) entered blocking state > bridge0: port 1(bridge_slave_0) entered forwarding state > =================================================================> BUG: KASAN: use-after-free in memcmp+0xb3/0xc0 lib/string.c:862 > Read of size 1 at addr ffff88809f1efe70 by task syz-executor1/8111 >[snip]> > Allocated by task 8111: > ?save_stack+0x45/0xd0 mm/kasan/common.c:73 > ?set_track mm/kasan/common.c:85 [inline] > ?__kasan_kmalloc mm/kasan/common.c:496 [inline] > ?__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469 > ?kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504 > ?kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3609 > ?kmalloc include/linux/slab.h:545 [inline] > ?kzalloc include/linux/slab.h:740 [inline] > ?br_multicast_new_group.part.0+0xdc/0x1a40 net/bridge/br_multicast.c:476 > ?br_multicast_new_group+0x19d/0x200 net/bridge/br_multicast.c:471 > ?br_multicast_add_group+0x4ce/0x7d0 net/bridge/br_multicast.c:552 > ?br_ip6_multicast_add_group net/bridge/br_multicast.c:626 [inline] > ?br_ip6_multicast_mld2_report net/bridge/br_multicast.c:1043 [inline] > ?br_multicast_ipv6_rcv net/bridge/br_multicast.c:1667 [inline] > ?br_multicast_rcv+0x24aa/0x4270 net/bridge/br_multicast.c:1705 > ?br_dev_xmit+0x7f4/0x1780 net/bridge/br_device.c:93 > ?__netdev_start_xmit include/linux/netdevice.h:4382 [inline] > ?netdev_start_xmit include/linux/netdevice.h:4391 [inline] > ?xmit_one net/core/dev.c:3278 [inline] > ?dev_hard_start_xmit+0x261/0xc70 net/core/dev.c:3294 > ?__dev_queue_xmit+0x2f8a/0x3a60 net/core/dev.c:3864 > ?dev_queue_xmit+0x18/0x20 net/core/dev.c:3897 > ?neigh_resolve_output net/core/neighbour.c:1476 [inline] > ?neigh_resolve_output+0x6a0/0xb30 net/core/neighbour.c:1456 > ?neigh_output include/net/neighbour.h:508 [inline] > ?ip6_finish_output2+0xc56/0x28e0 net/ipv6/ip6_output.c:120 > ?ip6_finish_output+0x577/0xc30 net/ipv6/ip6_output.c:154 > ?NF_HOOK_COND include/linux/netfilter.h:278 [inline] > ?ip6_output+0x23c/0xa00 net/ipv6/ip6_output.c:171 > ?dst_output include/net/dst.h:444 [inline] > ?NF_HOOK include/linux/netfilter.h:289 [inline] > ?NF_HOOK include/linux/netfilter.h:283 [inline] > ?mld_sendpack+0xa44/0xfd0 net/ipv6/mcast.c:1683 > ?mld_send_cr net/ipv6/mcast.c:1979 [inline] > ?mld_ifc_timer_expire+0x449/0x8a0 net/ipv6/mcast.c:2478 > ?call_timer_fn+0x254/0x900 kernel/time/timer.c:1325 > ?expire_timers kernel/time/timer.c:1362 [inline] > ?__run_timers+0x6fc/0xd50 kernel/time/timer.c:1681 > ?run_timer_softirq+0x52/0xb0 kernel/time/timer.c:1694 > ?__do_softirq+0x30b/0xb11 kernel/softirq.c:292 > > Freed by task 8111: > ?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:458 > ?kasan_slab_free+0xe/0x10 mm/kasan/common.c:466 > ?__cache_free mm/slab.c:3487 [inline] > ?kfree+0xcf/0x230 mm/slab.c:3806 > ?br_multicast_new_group.part.0+0x1489/0x1a40 net/bridge/br_multicast.c:486Weird, this is the kfree() on the error path of br_multicast_new_group() when rhashtable_lookup_insert_fast() fails, which means the entry should not be linked in the rhashtable or the hlist. All other frees are via kfree_rcu. I'll keep looking..> ?br_multicast_new_group+0x19d/0x200 net/bridge/br_multicast.c:471 > ?br_multicast_add_group+0x4ce/0x7d0 net/bridge/br_multicast.c:552 > ?br_ip6_multicast_add_group net/bridge/br_multicast.c:626 [inline] > ?br_ip6_multicast_mld2_report net/bridge/br_multicast.c:1043 [inline] > ?br_multicast_ipv6_rcv net/bridge/br_multicast.c:1667 [inline] > ?br_multicast_rcv+0x24aa/0x4270 net/bridge/br_multicast.c:1705 > ?br_dev_xmit+0x7f4/0x1780 net/bridge/br_device.c:93 > ?__netdev_start_xmit include/linux/netdevice.h:4382 [inline] > ?netdev_start_xmit include/linux/netdevice.h:4391 [inline] > ?xmit_one net/core/dev.c:3278 [inline] > ?dev_hard_start_xmit+0x261/0xc70 net/core/dev.c:3294 > ?__dev_queue_xmit+0x2f8a/0x3a60 net/core/dev.c:3864 > ?dev_queue_xmit+0x18/0x20 net/core/dev.c:3897 > ?neigh_resolve_output net/core/neighbour.c:1476 [inline] > ?neigh_resolve_output+0x6a0/0xb30 net/core/neighbour.c:1456 > ?neigh_output include/net/neighbour.h:508 [inline] > ?ip6_finish_output2+0xc56/0x28e0 net/ipv6/ip6_output.c:120 > ?ip6_finish_output+0x577/0xc30 net/ipv6/ip6_output.c:154 > ?NF_HOOK_COND include/linux/netfilter.h:278 [inline] > ?ip6_output+0x23c/0xa00 net/ipv6/ip6_output.c:171 > ?dst_output include/net/dst.h:444 [inline] > ?NF_HOOK include/linux/netfilter.h:289 [inline] > ?NF_HOOK include/linux/netfilter.h:283 [inline] > ?mld_sendpack+0xa44/0xfd0 net/ipv6/mcast.c:1683 > ?mld_send_cr net/ipv6/mcast.c:1979 [inline] > ?mld_ifc_timer_expire+0x449/0x8a0 net/ipv6/mcast.c:2478 > ?call_timer_fn+0x254/0x900 kernel/time/timer.c:1325 > ?expire_timers kernel/time/timer.c:1362 [inline] > ?__run_timers+0x6fc/0xd50 kernel/time/timer.c:1681 > ?run_timer_softirq+0x52/0xb0 kernel/time/timer.c:1694 > ?__do_softirq+0x30b/0xb11 kernel/softirq.c:292 > > The buggy address belongs to the object at ffff88809f1efe00 > ?which belongs to the cache kmalloc-192 of size 192 > The buggy address is located 112 bytes inside of > ?192-byte region [ffff88809f1efe00, ffff88809f1efec0) > The buggy address belongs to the page: > page:ffffea00027c7bc0 count:1 mapcount:0 mapping:ffff88812c3f0040 index:0x0 > flags: 0x1fffc0000000200(slab) > raw: 01fffc0000000200 ffffea00027df108 ffffea00027c7c48 ffff88812c3f0040 > raw: 0000000000000000 ffff88809f1ef000 0000000100000010 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ?ffff88809f1efd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ?ffff88809f1efd80: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff88809f1efe00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ???????????????????????????????????????????????????????????? ^ > ?ffff88809f1efe80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ?ffff88809f1eff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > =================================================================> > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller at googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot.