bisecting fixing commit since 3f2ecb86cb909da0b9157fd2952ad79924cbe5ae building syzkaller on 04201c0669446145fd9c347c5538da0ca13ff29b testing commit 3f2ecb86cb909da0b9157fd2952ad79924cbe5ae with gcc (GCC) 8.4.1 20210217 kernel signature: e979bb354d059664e9fcbb30a06f70b80fd540567e50e36326c64406ea796f5d run #0: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #1: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #2: crashed: KASAN: slab-out-of-bounds 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: slab-out-of-bounds 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: slab-out-of-bounds Read in ipvlan_queue_xmit run #10: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #11: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #12: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #13: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #14: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #15: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #16: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #17: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #18: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #19: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit testing current HEAD 29c52025152bab4c557d8174da58f1a4c8e70438 testing commit 29c52025152bab4c557d8174da58f1a4c8e70438 with gcc (GCC) 8.4.1 20210217 kernel signature: 63f1c51b05ed3be1dd0917366aecd0f1e1e8c7735452957481b26124293664d7 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: slab-out-of-bounds Read in ipvlan_queue_xmit run #3: crashed: KASAN: use-after-free Read in ipvlan_queue_xmit run #4: crashed: KASAN: slab-out-of-bounds Read in ipvlan_queue_xmit run #5: crashed: KASAN: use-after-free 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 revisions tested: 2, total time: 20m34.179178739s (build: 13m32.403994549s, test: 6m9.193328844s) the crash still happens on HEAD commit msg: Linux 4.14.221 crash: KASAN: use-after-free Read in ipvlan_queue_xmit batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 ================================================================== batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! BUG: KASAN: use-after-free in ether_addr_equal include/linux/etherdevice.h:321 [inline] BUG: KASAN: use-after-free in ipvlan_xmit_mode_l2 drivers/net/ipvlan/ipvlan_core.c:542 [inline] BUG: KASAN: use-after-free in ipvlan_queue_xmit+0xfe2/0x11e0 drivers/net/ipvlan/ipvlan_core.c:583 Read of size 4 at addr ffff888098c355bf by task syz-executor.4/9673 CPU: 1 PID: 9673 Comm: syz-executor.4 Not tainted 4.14.221-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x14b/0x1e7 lib/dump_stack.c:58 print_address_description.cold.6+0x9/0x1ca mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold.7+0x11a/0x2d3 mm/kasan/report.c:393 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 ether_addr_equal include/linux/etherdevice.h:321 [inline] ipvlan_xmit_mode_l2 drivers/net/ipvlan/ipvlan_core.c:542 [inline] ipvlan_queue_xmit+0xfe2/0x11e0 drivers/net/ipvlan/ipvlan_core.c:583 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! IPv6: ADDRCONF(NETDEV_UP): batadv_slave_0: link is not ready batman_adv: batadv0: Interface activated: batadv_slave_0 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 ipvlan_start_xmit+0x4a/0x150 drivers/net/ipvlan/ipvlan_main.c:286 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! __netdev_start_xmit include/linux/netdevice.h:4039 [inline] netdev_start_xmit include/linux/netdevice.h:4048 [inline] packet_direct_xmit+0x3ed/0x630 net/packet/af_packet.c:269 packet_snd.isra.30+0x9b6/0x2600 net/packet/af_packet.c:3024 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 packet_sendmsg+0x100f/0x27d0 net/packet/af_packet.c:3049 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:656 sock_write_iter+0x20d/0x400 net/socket.c:925 call_write_iter include/linux/fs.h:1778 [inline] aio_write+0x291/0x4e0 fs/aio.c:1553 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready io_submit_one fs/aio.c:1641 [inline] do_io_submit+0xb66/0x1290 fs/aio.c:1709 batman_adv: batadv0: Interface activated: batadv_slave_1 SYSC_io_submit fs/aio.c:1734 [inline] SyS_io_submit+0xb/0x10 fs/aio.c:1731 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x465a59 RSP: 002b:00007f4adf582188 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 RAX: ffffffffffffffda RBX: 000000000055bfe8 RCX: 0000000000465a59 RDX: 0000000020000080 RSI: 0000000000000001 RDI: 00007f4adf561000 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bfe8 R13: 00007fffa1b91b6f R14: 00007f4adf582300 R15: 0000000000022000 BUG: unable to handle kernel NULL pointer dereference at 0000000000000014 IP: nearest_obj include/linux/slab_def.h:94 [inline] IP: print_address_description.cold.6+0x4b/0x1ca mm/kasan/report.c:257 PGD 9a741067 P4D 9a741067 PUD 99a74067 PMD 0 Oops: 0000 [#1] PREEMPT SMP KASAN Modules linked in: CPU: 1 PID: 9673 Comm: syz-executor.4 Not tainted 4.14.221-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff888098fcc300 task.stack: ffff88809cf10000 RIP: 0010:nearest_obj include/linux/slab_def.h:94 [inline] RIP: 0010:print_address_description.cold.6+0x4b/0x1ca mm/kasan/report.c:257 RSP: 0018:ffff88809cf17388 EFLAGS: 00010002 RAX: ffff888098c355bf RBX: ffff888098c355bf RCX: dead0000ffffffff RDX: ffffea0002630d01 RSI: ffffffff87cc6e80 RDI: ffffed10139e2e68 RBP: ffff88809cf173b0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000028 R11: dffffc0000000000 R12: ffffea0002630d40 R13: ffff888098c355bf R14: 0000000000000000 R15: ffff888098c355bf FS: 00007f4adf582700(0000) GS:ffff8880ba700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000014 CR3: 000000009a740000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold.7+0x11a/0x2d3 mm/kasan/report.c:393 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429 ether_addr_equal include/linux/etherdevice.h:321 [inline] ipvlan_xmit_mode_l2 drivers/net/ipvlan/ipvlan_core.c:542 [inline] ipvlan_queue_xmit+0xfe2/0x11e0 drivers/net/ipvlan/ipvlan_core.c:583 ipvlan_start_xmit+0x4a/0x150 drivers/net/ipvlan/ipvlan_main.c:286 __netdev_start_xmit include/linux/netdevice.h:4039 [inline] netdev_start_xmit include/linux/netdevice.h:4048 [inline] packet_direct_xmit+0x3ed/0x630 net/packet/af_packet.c:269 packet_snd.isra.30+0x9b6/0x2600 net/packet/af_packet.c:3024 packet_sendmsg+0x100f/0x27d0 net/packet/af_packet.c:3049 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:656 sock_write_iter+0x20d/0x400 net/socket.c:925 call_write_iter include/linux/fs.h:1778 [inline] aio_write+0x291/0x4e0 fs/aio.c:1553 io_submit_one fs/aio.c:1641 [inline] do_io_submit+0xb66/0x1290 fs/aio.c:1709 SYSC_io_submit fs/aio.c:1734 [inline] SyS_io_submit+0xb/0x10 fs/aio.c:1731 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x465a59 RSP: 002b:00007f4adf582188 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 RAX: ffffffffffffffda RBX: 000000000055bfe8 RCX: 0000000000465a59 RDX: 0000000020000080 RSI: 0000000000000001 RDI: 00007f4adf561000 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bfe8 R13: 00007fffa1b91b6f R14: 00007f4adf582300 R15: 0000000000022000 Code: 54 24 20 4c 89 e0 f6 c2 01 0f 85 25 01 00 00 48 8b 00 f6 c4 01 0f 84 a6 00 00 00 4d 8b 74 24 30 48 89 d8 49 89 dd 49 8b 4c 24 08 <41> 8b 7e 14 48 29 c8 48 99 48 f7 ff 41 8b 46 24 49 29 d5 83 e8 RIP: nearest_obj include/linux/slab_def.h:94 [inline] RSP: ffff88809cf17388 RIP: print_address_description.cold.6+0x4b/0x1ca mm/kasan/report.c:257 RSP: ffff88809cf17388 CR2: 0000000000000014 ---[ end trace 736a8d30e7d44e1e ]---