bisecting fixing commit since 13d2ce42de8cb98ff952f8de6307f896203854c2 building syzkaller on 8f160dd5d603e9cd86705baad260794afa3e5cb3 testing commit 13d2ce42de8cb98ff952f8de6307f896203854c2 with gcc (GCC) 8.1.0 kernel signature: caa4236559c95099e7c62715bbef3cd75af89a6e1cf739fd88d638016b0cba24 run #0: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #1: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #2: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #3: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #4: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #5: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #6: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #7: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #8: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #9: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit testing current HEAD 675cc038067f0e530471c56a7442935f84669d95 testing commit 675cc038067f0e530471c56a7442935f84669d95 with gcc (GCC) 8.1.0 kernel signature: 3d10052a4f364e480c9c9a210670060494e5800882245a5f100b89e66de2620a run #0: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #1: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #2: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #3: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #4: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #5: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #6: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #7: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #8: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #9: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit revisions tested: 2, total time: 22m30.366748426s (build: 16m13.66941086s, test: 5m42.225493391s) the crash still happens on HEAD commit msg: Linux 4.19.167 crash: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready ================================================================== BUG: KASAN: slab-out-of-bounds in ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:533 [inline] BUG: KASAN: slab-out-of-bounds in ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:593 [inline] BUG: KASAN: slab-out-of-bounds in ipvlan_queue_xmit+0x89d/0x1630 drivers/net/ipvlan/ipvlan_core.c:654 Read of size 4 at addr ffff88809851bcbf by task syz-executor.3/9843 CPU: 1 PID: 9843 Comm: syz-executor.3 Not tainted 4.19.167-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+0x17c/0x22a lib/dump_stack.c:118 print_address_description.cold.6+0x9/0x211 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x307 mm/kasan/report.c:412 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:533 [inline] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:593 [inline] ipvlan_queue_xmit+0x89d/0x1630 drivers/net/ipvlan/ipvlan_core.c:654 ipvlan_start_xmit+0x4a/0x150 drivers/net/ipvlan/ipvlan_main.c:290 __netdev_start_xmit include/linux/netdevice.h:4333 [inline] netdev_start_xmit include/linux/netdevice.h:4347 [inline] dev_direct_xmit+0x2db/0x620 net/core/dev.c:3905 packet_direct_xmit+0xd6/0x140 net/packet/af_packet.c:246 packet_snd net/packet/af_packet.c:2988 [inline] packet_sendmsg+0x34f7/0x5f30 net/packet/af_packet.c:3013 IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:632 wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 sock_write_iter+0x215/0x420 net/socket.c:901 wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50 call_write_iter include/linux/fs.h:1821 [inline] aio_write+0x2e4/0x560 fs/aio.c:1574 __io_submit_one fs/aio.c:1858 [inline] io_submit_one+0x773/0x1c20 fs/aio.c:1909 __do_sys_io_submit fs/aio.c:1953 [inline] __se_sys_io_submit+0x112/0x390 fs/aio.c:1924 __x64_sys_io_submit+0x6e/0xb0 fs/aio.c:1924 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45e159 Code: 0d 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fa99cbe9c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e159 RDX: 0000000020000080 RSI: 0000000000000001 RDI: 00007fa99cbc9000 RBP: 000000000119bfc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c R13: 00007ffdd72cc3df R14: 00007fa99cbea9c0 R15: 000000000119bf8c Allocated by task 8494: save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:553 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:538 __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x50/0x70 mm/slab.c:3703 __kmalloc_reserve.isra.9+0x2c/0xc0 net/core/skbuff.c:137 pskb_expand_head+0x113/0xd80 net/core/skbuff.c:1464 netlink_trim+0x1a7/0x200 net/netlink/af_netlink.c:1300 netlink_broadcast_filtered+0x57/0x920 net/netlink/af_netlink.c:1497 netlink_broadcast+0xe/0x10 net/netlink/af_netlink.c:1542 nlmsg_multicast include/net/netlink.h:591 [inline] nlmsg_notify+0x6e/0x110 net/netlink/af_netlink.c:2498 rtnl_notify net/core/rtnetlink.c:736 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:3377 [inline] rtmsg_ifinfo_event.part.14+0x7f/0xb0 net/core/rtnetlink.c:3392 rtmsg_ifinfo_event net/core/rtnetlink.c:3400 [inline] rtmsg_ifinfo+0x4e/0x70 net/core/rtnetlink.c:3398 register_netdevice+0x9a7/0xfa0 net/core/dev.c:8769 ieee80211_if_add+0x929/0x16d0 net/mac80211/iface.c:1888 ieee80211_register_hw+0x26e5/0x36c0 net/mac80211/main.c:1160 mac80211_hwsim_new_radio+0x1a57/0x3750 drivers/net/wireless/mac80211_hwsim.c:2896 hwsim_new_radio_nl+0x517/0x8d0 drivers/net/wireless/mac80211_hwsim.c:3374 genl_family_rcv_msg+0x599/0x1000 net/netlink/genetlink.c:602 genl_rcv_msg+0xa7/0x140 net/netlink/genetlink.c:627 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2455 genl_rcv+0x23/0x40 net/netlink/genetlink.c:638 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x443/0x660 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x666/0xc50 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:632 __sys_sendto+0x1f2/0x2e0 net/socket.c:1787 __do_sys_sendto net/socket.c:1799 [inline] __se_sys_sendto net/socket.c:1795 [inline] __x64_sys_sendto+0xdc/0x1a0 net/socket.c:1795 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8494: save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x13c/0x220 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 skb_free_head+0x74/0x90 net/core/skbuff.c:554 skb_release_data+0x513/0x760 net/core/skbuff.c:574 skb_release_all+0x3d/0x50 net/core/skbuff.c:631 __kfree_skb net/core/skbuff.c:645 [inline] consume_skb+0x93/0x270 net/core/skbuff.c:705 netlink_broadcast_filtered+0x285/0x920 net/netlink/af_netlink.c:1520 netlink_broadcast+0xe/0x10 net/netlink/af_netlink.c:1542 nlmsg_multicast include/net/netlink.h:591 [inline] nlmsg_notify+0x6e/0x110 net/netlink/af_netlink.c:2498 rtnl_notify net/core/rtnetlink.c:736 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:3377 [inline] rtmsg_ifinfo_event.part.14+0x7f/0xb0 net/core/rtnetlink.c:3392 rtmsg_ifinfo_event net/core/rtnetlink.c:3400 [inline] rtmsg_ifinfo+0x4e/0x70 net/core/rtnetlink.c:3398 register_netdevice+0x9a7/0xfa0 net/core/dev.c:8769 ieee80211_if_add+0x929/0x16d0 net/mac80211/iface.c:1888 ieee80211_register_hw+0x26e5/0x36c0 net/mac80211/main.c:1160 mac80211_hwsim_new_radio+0x1a57/0x3750 drivers/net/wireless/mac80211_hwsim.c:2896 hwsim_new_radio_nl+0x517/0x8d0 drivers/net/wireless/mac80211_hwsim.c:3374 genl_family_rcv_msg+0x599/0x1000 net/netlink/genetlink.c:602 genl_rcv_msg+0xa7/0x140 net/netlink/genetlink.c:627 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2455 genl_rcv+0x23/0x40 net/netlink/genetlink.c:638 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x443/0x660 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x666/0xc50 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:632 __sys_sendto+0x1f2/0x2e0 net/socket.c:1787 __do_sys_sendto net/socket.c:1799 [inline] __se_sys_sendto net/socket.c:1795 [inline] __x64_sys_sendto+0xdc/0x1a0 net/socket.c:1795 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88809851b380 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 319 bytes to the right of 2048-byte region [ffff88809851b380, ffff88809851bb80) The buggy address belongs to the page: page:ffffea0002614680 count:1 mapcount:0 mapping:ffff88813bff6c40 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffffea000262ca08 ffffea000268ad08 ffff88813bff6c40 raw: 0000000000000000 ffff88809851a280 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809851bb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809851bc00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88809851bc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88809851bd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809851bd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================