bisecting fixing commit since 20b3a3dfdf6c55b50bbdc8e231a3dbf6bf965dc7 building syzkaller on 70c104a18f3d409bc6dde950b50258d3d280d99b testing commit 20b3a3dfdf6c55b50bbdc8e231a3dbf6bf965dc7 with gcc (GCC) 8.4.1 20210217 kernel signature: ac3b5a446ec118f5d1a6c0cc9f6656da487632ccafbc5c3624f8b9b527022348 run #0: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #1: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #2: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #3: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #4: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #5: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #6: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #7: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #8: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #9: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #10: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #11: crashed: INFO: rcu detected stall in rtnl_newlink run #12: crashed: INFO: rcu detected stall in rtnl_newlink run #13: crashed: INFO: rcu detected stall in rtnl_newlink run #14: crashed: INFO: rcu detected stall in rtnl_newlink run #15: crashed: INFO: rcu detected stall in rtnl_newlink run #16: crashed: INFO: rcu detected stall in rtnl_newlink run #17: crashed: INFO: rcu detected stall in rtnl_newlink run #18: crashed: INFO: rcu detected stall in rtnl_newlink run #19: crashed: INFO: rcu detected stall in rtnl_newlink testing current HEAD 2965db2e004cf9c92b87c1f559e9812c0ae878c1 testing commit 2965db2e004cf9c92b87c1f559e9812c0ae878c1 with gcc (GCC) 8.4.1 20210217 kernel signature: 3971546b7d3bd9436dce40ec9f9fcaaac6967af679e0ee6dec9c891679613f09 run #0: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #1: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #2: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #3: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #4: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #5: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #6: crashed: BUG: soft lockup in batadv_iv_send_outstanding_bat_ogm_packet run #7: crashed: INFO: rcu detected stall in rtnl_newlink run #8: crashed: INFO: rcu detected stall in rtnl_newlink run #9: crashed: INFO: rcu detected stall in rtnl_newlink revisions tested: 2, total time: 31m37.001086455s (build: 21m1.220049747s, test: 9m46.22384013s) the crash still happens on HEAD commit msg: Linux 4.19.188 crash: INFO: rcu detected stall in rtnl_newlink batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (10493 ticks this GP) idle=1aa/1/0x4000000000000002 softirq=8812/8821 fqs=5222 rcu: (t=10500 jiffies g=4805 q=1599) NMI backtrace for cpu 1 CPU: 1 PID: 7155 Comm: syz-executor.1 Not tainted 4.19.188-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/0x226 lib/dump_stack.c:118 nmi_cpu_backtrace.cold.0+0x3c/0x78 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xf5/0x120 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1340 print_cpu_stall kernel/rcu/tree.c:1478 [inline] check_cpu_stall kernel/rcu/tree.c:1550 [inline] __rcu_pending kernel/rcu/tree.c:3293 [inline] rcu_pending kernel/rcu/tree.c:3336 [inline] rcu_check_callbacks.cold.62+0x5b1/0xd89 kernel/rcu/tree.c:2682 update_process_times+0x2a/0x60 kernel/time/timer.c:1650 tick_sched_handle.isra.5+0x6b/0x130 kernel/time/tick-sched.c:168 tick_sched_timer+0x3c/0xf0 kernel/time/tick-sched.c:1278 __run_hrtimer kernel/time/hrtimer.c:1419 [inline] __hrtimer_run_queues+0x2fa/0xaa0 kernel/time/hrtimer.c:1481 hrtimer_interrupt+0x2e2/0x760 kernel/time/hrtimer.c:1539 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1071 [inline] smp_apic_timer_interrupt+0x114/0x540 arch/x86/kernel/apic/apic.c:1096 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:lock_release+0x44b/0x840 kernel/locking/lockdep.c:3929 Code: 00 00 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 55 03 00 00 48 83 3d 5c 69 07 07 00 0f 84 44 02 00 00 48 8b bd 68 ff ff ff 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 48 c7 04 03 00 00 00 RSP: 0018:ffff8881dcc7ead0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: 1ffff1103b98fd5d RCX: 1ffff1103b80c9b7 RDX: 1ffffffff10a3f71 RSI: 0000000000000003 RDI: 0000000000000286 RBP: ffff8881dcc7eb70 R08: 0000000000000000 R09: ffffed103a50c12e R10: ffffed103a50c12e R11: ffff8881d2860973 R12: ffff8881dc064540 R13: 0000000000000002 R14: ffff8881dc064dc0 R15: ffff8881dc064540 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:174 [inline] _raw_spin_unlock_bh+0x1a/0x40 kernel/locking/spinlock.c:200 spin_unlock_bh include/linux/spinlock.h:374 [inline] batadv_tt_local_purge_pending_clients+0x22a/0x320 net/batman-adv/translation-table.c:3924 batadv_tt_local_resize_to_mtu+0x8f/0xf0 net/batman-adv/translation-table.c:4208 batadv_update_min_mtu net/batman-adv/hard-interface.c:637 [inline] batadv_hardif_activate_interface.part.3.cold.8+0xcb/0x313 net/batman-adv/hard-interface.c:664 batadv_hardif_activate_interface net/batman-adv/hard-interface.c:825 [inline] batadv_hardif_enable_interface+0x987/0xa40 net/batman-adv/hard-interface.c:817 batadv_softif_slave_add+0x7f/0xd0 net/batman-adv/soft-interface.c:898 do_set_master net/core/rtnetlink.c:2321 [inline] do_set_master+0x171/0x200 net/core/rtnetlink.c:2295 do_setlink+0x94c/0x2ec0 net/core/rtnetlink.c:2455 rtnl_newlink+0x975/0x1360 net/core/rtnetlink.c:3077 rtnetlink_rcv_msg+0x34f/0x950 net/core/rtnetlink.c:4778 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2455 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4796 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x443/0x660 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x667/0xc60 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:632 ___sys_sendmsg+0x647/0x950 net/socket.c:2115 __sys_sendmsg+0xd9/0x180 net/socket.c:2153 __do_sys_sendmsg net/socket.c:2162 [inline] __se_sys_sendmsg net/socket.c:2160 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2160 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x463b49 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:00007fc179c66188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000055bf00 RCX: 0000000000463b49 RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000004 RBP: 00000000004ae538 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bf00 R13: 00007fff9ee4f14f R14: 00007fc179c66300 R15: 0000000000022000 net_ratelimit: 6700 callbacks suppressed batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) net_ratelimit: 7013 callbacks suppressed batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224) batman_adv: batadv0: Forced to purge local tt entries to fit new maximum fragment MTU (-224)