bisecting fixing commit since 675cc038067f0e530471c56a7442935f84669d95 building syzkaller on 65a7a8540d29e72622fca06522587f7e66539fd3 testing commit 675cc038067f0e530471c56a7442935f84669d95 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: c18c4f3b3d32302508095771b9330eb2d80b6a4b4cffa16a696f01163bc3869c all runs: crashed: BUG: unable to handle kernel paging request in do_csum testing current HEAD 59456c9cc40c8f75b5a7efa0fe1f211d9c6fcaf1 testing commit 59456c9cc40c8f75b5a7efa0fe1f211d9c6fcaf1 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 18ce26f7d4bd61dd61072e10ed094a2261fd9ee7f2d7f333b02e866ff2464e76 all runs: crashed: BUG: unable to handle kernel paging request in do_csum revisions tested: 2, total time: 28m4.44916397s (build: 21m17.394604572s, test: 6m23.421328595s) the crash still happens on HEAD commit msg: Linux 4.19.204 crash: BUG: unable to handle kernel paging request in do_csum wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50 IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 BUG: unable to handle kernel paging request at ffff8880bfffd000 PGD c801067 P4D c801067 PUD 23ffff067 PMD 23fffe067 PTE 0 IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 9922 Comm: syz-executor.2 Not tainted 4.19.204-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:do_csum+0xea/0x2f0 arch/x86/lib/csum-partial_64.c:72 Code: 48 01 c3 44 89 f1 41 c1 ee 04 d1 e9 45 85 f6 0f 84 d4 01 00 00 41 8d 46 ff 31 d2 48 83 c0 01 48 c1 e0 06 4c 01 e0 49 03 1c 24 <49> 13 5c 24 08 49 13 5c 24 10 49 13 5c 24 18 49 13 5c 24 20 49 13 RSP: 0018:ffff8880970b7348 EFLAGS: 00010282 RAX: ffff888198609278 RBX: e0fd538ca33f9a58 RCX: 000000001ffffffd RDX: 0000000000000000 RSI: ffffffffffffffec RDI: ffff8880986092b8 RBP: ffff8880970b7370 R08: ffff8880a33edc90 R09: 0000000000000100 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880bfffcff8 R13: 0000000000000000 R14: 0000000003ffffff R15: ffff8880986092b8 FS: 00007f0e2919a700(0000) GS:ffff8880ba200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff8880bfffd000 CR3: 000000009acb3000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: csum_partial+0xc/0x20 arch/x86/lib/csum-partial_64.c:136 lco_csum include/linux/skbuff.h:4247 [inline] gre_checksum include/net/gre.h:105 [inline] gre_build_header include/net/gre.h:140 [inline] __gre_xmit+0x786/0x8e0 net/ipv4/ip_gre.c:443 ipgre_xmit+0x396/0x870 net/ipv4/ip_gre.c:703 __netdev_start_xmit include/linux/netdevice.h:4345 [inline] netdev_start_xmit include/linux/netdevice.h:4359 [inline] xmit_one net/core/dev.c:3256 [inline] dev_hard_start_xmit+0x160/0x6e0 net/core/dev.c:3272 __dev_queue_xmit+0x1ca6/0x2900 net/core/dev.c:3838 dev_queue_xmit+0xb/0x10 net/core/dev.c:3871 packet_snd net/packet/af_packet.c:2988 [inline] packet_sendmsg+0x367a/0x6cf0 net/packet/af_packet.c:3013 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:661 kernel_sendmsg+0x26/0x30 net/socket.c:681 sock_no_sendpage+0xfd/0x140 net/core/sock.c:2668 kernel_sendpage+0x60/0xd0 net/socket.c:3581 sock_sendpage+0x6d/0xd0 net/socket.c:912 pipe_to_sendpage+0x212/0x430 fs/splice.c:452 splice_from_pipe_feed fs/splice.c:503 [inline] __splice_from_pipe+0x2cb/0x720 fs/splice.c:627 splice_from_pipe+0xbb/0x120 fs/splice.c:662 generic_splice_sendpage+0x10/0x20 fs/splice.c:833 do_splice_from fs/splice.c:852 [inline] do_splice fs/splice.c:1154 [inline] __do_sys_splice fs/splice.c:1428 [inline] __se_sys_splice+0x71e/0x17e0 fs/splice.c:1408 __x64_sys_splice+0xdc/0x1a0 fs/splice.c:1408 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465b09 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0e2919a188 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465b09 RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00000000004b069f R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007fff920a622f R14: 00007f0e2919a300 R15: 0000000000022000 Modules linked in: CR2: ffff8880bfffd000 ---[ end trace 600559cd463f85e1 ]--- RIP: 0010:do_csum+0xea/0x2f0 arch/x86/lib/csum-partial_64.c:72 Code: 48 01 c3 44 89 f1 41 c1 ee 04 d1 e9 45 85 f6 0f 84 d4 01 00 00 41 8d 46 ff 31 d2 48 83 c0 01 48 c1 e0 06 4c 01 e0 49 03 1c 24 <49> 13 5c 24 08 49 13 5c 24 10 49 13 5c 24 18 49 13 5c 24 20 49 13 RSP: 0018:ffff8880970b7348 EFLAGS: 00010282 RAX: ffff888198609278 RBX: e0fd538ca33f9a58 RCX: 000000001ffffffd RDX: 0000000000000000 RSI: ffffffffffffffec RDI: ffff8880986092b8 RBP: ffff8880970b7370 R08: ffff8880a33edc90 R09: 0000000000000100 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880bfffcff8 R13: 0000000000000000 R14: 0000000003ffffff R15: ffff8880986092b8 FS: 00007f0e2919a700(0000) GS:ffff8880ba200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff8880bfffd000 CR3: 000000009acb3000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 ieee80211 phy12: Selected rate control algorithm 'minstrel_ht' DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 BUG: unable to handle kernel paging request at ffff8880bfffd000 ---------------- Code disassembly (best guess): 0: 48 01 c3 add %rax,%rbx 3: 44 89 f1 mov %r14d,%ecx 6: 41 c1 ee 04 shr $0x4,%r14d a: d1 e9 shr %ecx c: 45 85 f6 test %r14d,%r14d f: 0f 84 d4 01 00 00 je 0x1e9 15: 41 8d 46 ff lea -0x1(%r14),%eax 19: 31 d2 xor %edx,%edx 1b: 48 83 c0 01 add $0x1,%rax 1f: 48 c1 e0 06 shl $0x6,%rax 23: 4c 01 e0 add %r12,%rax 26: 49 03 1c 24 add (%r12),%rbx * 2a: 49 13 5c 24 08 adc 0x8(%r12),%rbx <-- trapping instruction 2f: 49 13 5c 24 10 adc 0x10(%r12),%rbx 34: 49 13 5c 24 18 adc 0x18(%r12),%rbx 39: 49 13 5c 24 20 adc 0x20(%r12),%rbx 3e: 49 rex.WB 3f: 13 .byte 0x13