bisecting fixing commit since f5d582777bcb1c7ff19a5a2343f66ea01de401c6 building syzkaller on 7795ae03c0d2358a40130693e40e0fcab5232ed2 testing commit f5d582777bcb1c7ff19a5a2343f66ea01de401c6 with gcc (GCC) 8.1.0 kernel signature: c1c860f63b196e300082ed76fc100e952758bf77 run #0: crashed: kernel BUG at arch/x86/mm/physaddr.c:LINE! run #1: crashed: kernel BUG at arch/x86/mm/physaddr.c:LINE! run #2: crashed: BUG: corrupted list in copy_process run #3: crashed: kernel BUG at arch/x86/mm/physaddr.c:LINE! run #4: crashed: BUG: unable to handle kernel paging request in free_block run #5: crashed: BUG: unable to handle kernel paging request in kmem_cache_alloc_node run #6: OK run #7: OK run #8: OK run #9: OK testing current HEAD b3a987b0264d3ddbb24293ebff10eddfc472f653 testing commit b3a987b0264d3ddbb24293ebff10eddfc472f653 with gcc (GCC) 8.1.0 kernel signature: 9fb429fd645cb731fbb89675d1af304a354190eb all runs: crashed: BUG: using smp_processor_id() in preemptible [ADDR] code: syz-executor revisions tested: 2, total time: 25m45.71284588s (build: 11m2.968345279s, test: 13m57.661991736s) the crash still happens on HEAD commit msg: Linux 5.5-rc6 crash: BUG: using smp_processor_id() in preemptible [ADDR] code: syz-executor 8021q: adding VLAN 0 to HW filter on device team0 tipc: Started in network mode tipc: Own node identity ac14142, cluster identity 4711 tipc: New replicast peer: 0.0.0.0 check_preemption_disabled: 3 callbacks suppressed BUG: using smp_processor_id() in preemptible [00000000] code: syz-executor0/7595 caller is dst_cache_get+0x33/0xa0 net/core/dst_cache.c:68 CPU: 1 PID: 7595 Comm: syz-executor0 Not tainted 5.5.0-rc6-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+0x12d/0x187 lib/dump_stack.c:118 check_preemption_disabled lib/smp_processor_id.c:47 [inline] debug_smp_processor_id.cold.1+0x84/0x9e lib/smp_processor_id.c:57 dst_cache_get+0x33/0xa0 net/core/dst_cache.c:68 tipc_udp_xmit.isra.15+0xab/0xcd0 net/tipc/udp_media.c:164 tipc_udp_send_msg+0x229/0x3d0 net/tipc/udp_media.c:257 tipc_bearer_xmit_skb+0x1a5/0x370 net/tipc/bearer.c:525 tipc_enable_bearer+0x7ef/0xb00 net/tipc/bearer.c:330 __tipc_nl_bearer_enable+0x265/0x390 net/tipc/bearer.c:994 tipc_nl_bearer_enable+0x1d/0x30 net/tipc/bearer.c:1002 genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline] genl_family_rcv_msg net/netlink/genetlink.c:717 [inline] genl_rcv_msg+0x5e1/0x10f0 net/netlink/genetlink.c:734 netlink_rcv_skb+0x13f/0x380 net/netlink/af_netlink.c:2477 genl_rcv+0x23/0x40 net/netlink/genetlink.c:745 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x463/0x6b0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x7b0/0xcb0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xe6/0x110 net/socket.c:659 ____sys_sendmsg+0x603/0x980 net/socket.c:2330 ___sys_sendmsg+0xe4/0x160 net/socket.c:2384 __sys_sendmsg+0xd9/0x180 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg net/socket.c:2424 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2424 do_syscall_64+0xd0/0x600 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4577c9 Code: fd b3 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f1553df1c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004577c9 RDX: 0000000000000080 RSI: 0000000020001e40 RDI: 0000000000000003 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1553df26d4 R13: 00000000004c42db R14: 00000000004d7220 R15: 00000000ffffffff BUG: using smp_processor_id() in preemptible [00000000] code: syz-executor0/7595 caller is dst_cache_set_ip4+0x97/0x2e0 net/core/dst_cache.c:98 CPU: 1 PID: 7595 Comm: syz-executor0 Not tainted 5.5.0-rc6-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+0x12d/0x187 lib/dump_stack.c:118 check_preemption_disabled lib/smp_processor_id.c:47 [inline] debug_smp_processor_id.cold.1+0x84/0x9e lib/smp_processor_id.c:57 dst_cache_set_ip4+0x97/0x2e0 net/core/dst_cache.c:98 tipc_udp_xmit.isra.15+0x7aa/0xcd0 net/tipc/udp_media.c:182 tipc_udp_send_msg+0x229/0x3d0 net/tipc/udp_media.c:257 tipc_bearer_xmit_skb+0x1a5/0x370 net/tipc/bearer.c:525 tipc_enable_bearer+0x7ef/0xb00 net/tipc/bearer.c:330 __tipc_nl_bearer_enable+0x265/0x390 net/tipc/bearer.c:994 tipc_nl_bearer_enable+0x1d/0x30 net/tipc/bearer.c:1002 genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline] genl_family_rcv_msg net/netlink/genetlink.c:717 [inline] genl_rcv_msg+0x5e1/0x10f0 net/netlink/genetlink.c:734 netlink_rcv_skb+0x13f/0x380 net/netlink/af_netlink.c:2477 genl_rcv+0x23/0x40 net/netlink/genetlink.c:745 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x463/0x6b0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x7b0/0xcb0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xe6/0x110 net/socket.c:659 ____sys_sendmsg+0x603/0x980 net/socket.c:2330 ___sys_sendmsg+0xe4/0x160 net/socket.c:2384 __sys_sendmsg+0xd9/0x180 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg net/socket.c:2424 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2424 do_syscall_64+0xd0/0x600 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4577c9 Code: fd b3 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f1553df1c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004577c9 RDX: 0000000000000080 RSI: 0000000020001e40 RDI: 0000000000000003 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1553df26d4 R13: 00000000004c42db R14: 00000000004d7220 R15: 00000000ffffffff ------------[ cut here ]------------ WARNING: CPU: 1 PID: 16 at include/net/dst.h:228 atomic_fetch_add_unless include/linux/atomic-fallback.h:1089 [inline] WARNING: CPU: 1 PID: 16 at include/net/dst.h:228 atomic_add_unless include/linux/atomic-fallback.h:1111 [inline] WARNING: CPU: 1 PID: 16 at include/net/dst.h:228 atomic_inc_not_zero include/linux/atomic-fallback.h:1127 [inline] WARNING: CPU: 1 PID: 16 at include/net/dst.h:228 dst_hold include/net/dst.h:228 [inline] WARNING: CPU: 1 PID: 16 at include/net/dst.h:228 dst_cache_per_cpu_get.isra.3+0x208/0x410 net/core/dst_cache.c:48 tipc: Enabled bearer , priority 10