bisecting fixing commit since 2034d6f0838e465dd8f120c4e946d8444b4bb5df building syzkaller on 6a81331a1d4c744da9204d02ec88d558f7eea9c9 testing commit 2034d6f0838e465dd8f120c4e946d8444b4bb5df with gcc (GCC) 8.4.1 20210217 kernel signature: 7a9d1767605cbdc51fac0b859ce2ed2caaddbfcb30625a45d35507a927e5e391 all runs: crashed: BUG: soft lockup in netlink_sendmsg testing current HEAD 97a8651cadce7c2b7c4d8f108b392eff31fe2c08 testing commit 97a8651cadce7c2b7c4d8f108b392eff31fe2c08 with gcc (GCC) 8.4.1 20210217 kernel signature: c04864a8a1e55ed83ea1e321b679b97381ceac4ff564106705604086418cc8e9 all runs: crashed: BUG: soft lockup in netlink_sendmsg revisions tested: 2, total time: 34m13.043845268s (build: 20m4.220457018s, test: 13m32.550259244s) the crash still happens on HEAD commit msg: Linux 4.19.189 crash: BUG: soft lockup in netlink_sendmsg Bluetooth: hci3: command 0x0419 tx timeout Bluetooth: hci2: command 0x0419 tx timeout Bluetooth: hci5: command 0x0419 tx timeout Bluetooth: hci4: command 0x0419 tx timeout watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [syz-executor.2:13019] Modules linked in: irq event stamp: 782405 hardirqs last enabled at (782404): [] seqcount_lockdep_reader_access include/linux/seqlock.h:83 [inline] hardirqs last enabled at (782404): [] read_seqcount_begin include/linux/seqlock.h:164 [inline] hardirqs last enabled at (782404): [] ktime_get kernel/time/timekeeping.c:756 [inline] hardirqs last enabled at (782404): [] ktime_get+0x1a0/0x230 kernel/time/timekeeping.c:746 hardirqs last disabled at (782405): [] trace_hardirqs_off_thunk+0x1a/0x1c softirqs last enabled at (136): [] spin_unlock_bh include/linux/spinlock.h:374 [inline] softirqs last enabled at (136): [] release_sock+0x11f/0x180 net/core/sock.c:2892 softirqs last disabled at (144): [] __dev_queue_xmit+0x20b/0x2900 net/core/dev.c:3773 CPU: 0 PID: 13019 Comm: syz-executor.2 Not tainted 4.19.189-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:cake_heapify+0x12/0x300 net/sched/sch_cake.c:1369 Code: ff ff 89 55 d0 89 75 d4 e8 fb ba 52 fb 8b 55 d0 8b 75 d4 e9 73 fe ff ff 48 b8 00 00 00 00 00 fc ff df 55 89 f2 48 89 e5 41 57 <49> 89 ff 41 56 41 55 41 54 53 0f b7 de 48 8d 7c 5f 18 48 83 ec 10 RSP: 0018:ffff88808efef4e8 EFLAGS: 00000216 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: 00000000000002af RCX: 0000000000000017 RDX: 00000000000002b0 RSI: 00000000000002b0 RDI: ffff88808db212c0 RBP: ffff88808efef4f0 R08: 0000000000000000 R09: 0000000000000000 R10: fffffbfff15df601 R11: 00000000ab42cdf1 R12: 00000013ef3aae95 R13: 0000000000000000 R14: ffff88808db21040 R15: dffffc0000000000 FS: 00007f40793c1700(0000) GS:ffff8880ba200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001d24708 CR3: 00000000a9429000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cake_drop net/sched/sch_cake.c:1468 [inline] cake_enqueue+0x1186/0x3b00 net/sched/sch_cake.c:1844 __dev_xmit_skb net/core/dev.c:3494 [inline] __dev_queue_xmit+0x1098/0x2900 net/core/dev.c:3807 dev_queue_xmit+0xb/0x10 net/core/dev.c:3871 __netlink_deliver_tap_skb net/netlink/af_netlink.c:303 [inline] __netlink_deliver_tap net/netlink/af_netlink.c:321 [inline] netlink_deliver_tap+0x77e/0xb00 net/netlink/af_netlink.c:334 netlink_deliver_tap_kernel net/netlink/af_netlink.c:343 [inline] netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] netlink_unicast+0x412/0x660 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: 0033:0x466459 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:00007f40793c1188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459 RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000005 RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007ffe5204e60f R14: 00007f40793c1300 R15: 0000000000022000 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x12/0x20 arch/x86/include/asm/irqflags.h:60