bisecting fixing commit since 6663cf821c133b36dee65fb9eb2d976abc706512 building syzkaller on 6ecc6d0f7a55902fe3efbb519ce9ef5e13f15a92 testing commit 6663cf821c133b36dee65fb9eb2d976abc706512 with gcc (GCC) 8.1.0 kernel signature: eb35b7c409fcc0367ae04f70db4388f6abf80d6a run #0: crashed: general protection fault in __queue_work run #1: OK run #2: OK run #3: OK run #4: OK run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK testing current HEAD 1f2565780e9b7218cf92c7630130e82dcc0fe9c2 testing commit 1f2565780e9b7218cf92c7630130e82dcc0fe9c2 with gcc (GCC) 8.1.0 kernel signature: faf9e2fc4695adc5e45aeacdcb143eae4dbd8e03 all runs: crashed: BUG: using smp_processor_id() in preemptible [ADDR] code: syz-executor revisions tested: 2, total time: 24m11.67209033s (build: 10m30.24469918s, test: 12m54.817966339s) the crash still happens on HEAD commit msg: xen-netback: remove 'hotplug-status' once it has served its purpose crash: BUG: using smp_processor_id() in preemptible [ADDR] code: syz-executor 8021q: adding VLAN 0 to HW filter on device batadv0 8021q: adding VLAN 0 to HW filter on device batadv0 tipc: Started in network mode tipc: Own node identity 7f000001, cluster identity 4711 check_preemption_disabled: 8 callbacks suppressed BUG: using smp_processor_id() in preemptible [00000000] code: syz-executor.0/7326 caller is dst_cache_get+0x33/0xa0 net/core/dst_cache.c:68 CPU: 0 PID: 7326 Comm: syz-executor.0 Not tainted 5.5.0-rc1-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+0x31e/0x3d0 net/tipc/udp_media.c:244 tipc_bearer_xmit_skb+0x1a5/0x370 net/tipc/bearer.c:526 tipc_enable_bearer+0x859/0xbb0 net/tipc/bearer.c:331 __tipc_nl_bearer_enable+0x265/0x390 net/tipc/bearer.c:995 sctp: failed to load transform for md5: -2 tipc_nl_bearer_enable+0x1d/0x30 net/tipc/bearer.c:1003 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:643 [inline] sock_sendmsg+0xe6/0x110 net/socket.c:663 ____sys_sendmsg+0x603/0x980 net/socket.c:2342 ___sys_sendmsg+0xe4/0x160 net/socket.c:2396 __sys_sendmsg+0xd9/0x180 net/socket.c:2429 __do_sys_sendmsg net/socket.c:2438 [inline] __se_sys_sendmsg net/socket.c:2436 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2436 do_syscall_64+0xd0/0x600 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457f89 Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fe7f2e8dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457f89 RDX: 0000000000000004 RSI: 0000000020000000 RDI: 000000000000000f RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe7f2e8e6d4 R13: 00000000004c52ba R14: 00000000004d9038 R15: 00000000ffffffff BUG: using smp_processor_id() in preemptible [00000000] code: syz-executor.0/7326 caller is dst_cache_set_ip4+0x97/0x2e0 net/core/dst_cache.c:98 CPU: 0 PID: 7326 Comm: syz-executor.0 Not tainted 5.5.0-rc1-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+0x31e/0x3d0 net/tipc/udp_media.c:244 tipc_bearer_xmit_skb+0x1a5/0x370 net/tipc/bearer.c:526 tipc_enable_bearer+0x859/0xbb0 net/tipc/bearer.c:331 __tipc_nl_bearer_enable+0x265/0x390 net/tipc/bearer.c:995 tipc_nl_bearer_enable+0x1d/0x30 net/tipc/bearer.c:1003 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:643 [inline] sock_sendmsg+0xe6/0x110 net/socket.c:663 ____sys_sendmsg+0x603/0x980 net/socket.c:2342 ___sys_sendmsg+0xe4/0x160 net/socket.c:2396 __sys_sendmsg+0xd9/0x180 net/socket.c:2429 __do_sys_sendmsg net/socket.c:2438 [inline] __se_sys_sendmsg net/socket.c:2436 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2436 do_syscall_64+0xd0/0x600 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457f89 Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fe7f2e8dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457f89 RDX: 0000000000000004 RSI: 0000000020000000 RDI: 000000000000000f RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe7f2e8e6d4 R13: 00000000004c52ba R14: 00000000004d9038 R15: 00000000ffffffff ------------[ cut here ]------------ WARNING: CPU: 0 PID: 9 at include/net/dst.h:228 atomic_fetch_add_unless include/linux/atomic-fallback.h:1089 [inline] WARNING: CPU: 0 PID: 9 at include/net/dst.h:228 atomic_add_unless include/linux/atomic-fallback.h:1111 [inline] WARNING: CPU: 0 PID: 9 at include/net/dst.h:228 atomic_inc_not_zero include/linux/atomic-fallback.h:1127 [inline] WARNING: CPU: 0 PID: 9 at include/net/dst.h:228 dst_hold include/net/dst.h:228 [inline] WARNING: CPU: 0 PID: 9 at include/net/dst.h:228 dst_cache_per_cpu_get.isra.3+0x208/0x410 net/core/dst_cache.c:48