bisecting fixing commit since 7cc2a8ea104820dd9e702202621e8fd4d9f6c8cf building syzkaller on 510951950dc0ee69cfdaf746061d3dbe31b49fd8 testing commit 7cc2a8ea104820dd9e702202621e8fd4d9f6c8cf with gcc (GCC) 8.4.1 20210217 kernel signature: 1a1d2595ef8b42cb606e33e16b65cfdcc5769cddd33209112c5bdb2507607901 run #0: crashed: BUG: soft lockup in smp_call_function run #1: crashed: BUG: soft lockup in smp_call_function run #2: crashed: BUG: soft lockup in smp_call_function run #3: crashed: BUG: soft lockup in smp_call_function run #4: crashed: BUG: soft lockup in smp_call_function run #5: crashed: BUG: soft lockup in smp_call_function run #6: crashed: BUG: soft lockup in smp_call_function run #7: crashed: BUG: soft lockup in smp_call_function run #8: crashed: BUG: workqueue lockup run #9: crashed: BUG: soft lockup in smp_call_function run #10: crashed: BUG: soft lockup in smp_call_function run #11: crashed: BUG: soft lockup in smp_call_function run #12: crashed: BUG: workqueue lockup run #13: crashed: BUG: soft lockup in smp_call_function run #14: crashed: BUG: soft lockup in smp_call_function run #15: crashed: BUG: soft lockup in smp_call_function run #16: crashed: no output from test machine run #17: crashed: no output from test machine run #18: crashed: no output from test machine run #19: crashed: no output from test machine testing current HEAD 1678e493d530e7977cce34e59a86bb86f3c5631e testing commit 1678e493d530e7977cce34e59a86bb86f3c5631e with gcc (GCC) 10.2.1 20210217 kernel signature: 7c1825a04ae1b3784848cef247c5d55af45d785a4bc5b81b7ad620b32a1e56cd run #0: crashed: BUG: workqueue lockup run #1: crashed: BUG: soft lockup in smp_call_function run #2: crashed: BUG: workqueue lockup run #3: crashed: BUG: soft lockup in smp_call_function run #4: crashed: BUG: soft lockup in smp_call_function run #5: crashed: BUG: soft lockup in smp_call_function run #6: crashed: INFO: rcu detected stall in do_idle run #7: crashed: BUG: soft lockup in smp_call_function run #8: crashed: BUG: soft lockup in smp_call_function run #9: crashed: BUG: soft lockup in smp_call_function revisions tested: 2, total time: 28m45.476871807s (build: 12m32.333594952s, test: 15m23.383945978s) the crash still happens on HEAD commit msg: Merge tag 'lto-v5.12-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux crash: BUG: soft lockup in smp_call_function watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [systemd-timesyn:4394] Modules linked in: irq event stamp: 87440 hardirqs last enabled at (87439): [] asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632 hardirqs last disabled at (87440): [] sysvec_apic_timer_interrupt+0xb/0xc0 arch/x86/kernel/apic/apic.c:1100 softirqs last enabled at (83052): [] sock_orphan include/net/sock.h:1895 [inline] softirqs last enabled at (83052): [] sk_common_release+0x126/0x2e0 net/core/sock.c:3294 softirqs last disabled at (83050): [] sock_orphan include/net/sock.h:1891 [inline] softirqs last disabled at (83050): [] sk_common_release+0xb0/0x2e0 net/core/sock.c:3294 CPU: 0 PID: 4394 Comm: systemd-timesyn Not tainted 5.12.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:csd_lock_wait kernel/smp.c:228 [inline] RIP: 0010:smp_call_function_single+0x137/0x410 kernel/smp.c:516 Code: 00 48 8b 44 24 18 44 89 e7 4c 89 74 24 58 48 8d 74 24 40 48 89 44 24 50 e8 76 fb ff ff 41 89 c4 8b 44 24 48 a8 01 74 0a f3 90 <8b> 44 24 48 a8 01 75 f6 bf 01 00 00 00 e8 37 19 e8 ff 65 8b 05 00 RSP: 0018:ffffc90002677aa0 EFLAGS: 00000202 RAX: 0000000000000011 RBX: 1ffff920004cef58 RCX: ffffffff835893f2 RDX: ffffed103eca6ec9 RSI: 0000000000000008 RDI: ffff8881f6537640 RBP: ffffc90002677b68 R08: 00000000f6437600 R09: ffff8881f6537647 R10: ffffed103eca6ec8 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001 FS: 00007f43f2a4c8c0(0000) GS:ffff8881f6400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055ef09c2dd30 CR3: 000000010462a004 CR4: 00000000001706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: smp_call_function_many kernel/smp.c:715 [inline] smp_call_function kernel/smp.c:737 [inline] on_each_cpu+0x3e/0x170 kernel/smp.c:836 clock_was_set+0x13/0x20 kernel/time/hrtimer.c:889 timekeeping_inject_offset+0x324/0x4c0 kernel/time/timekeeping.c:1374 do_adjtimex+0x1ad/0x730 kernel/time/timekeeping.c:2395 do_clock_adjtime kernel/time/posix-timers.c:1109 [inline] __do_sys_clock_adjtime+0x10c/0x1d0 kernel/time/posix-timers.c:1121 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f43f1e411b7 Code: 73 01 c3 48 8b 0d e1 fc 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 31 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b1 fc 2a 00 f7 d8 64 89 01 48 RSP: 002b:00007fff6b6665b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00005604a603a630 RCX: 00007f43f1e411b7 RDX: ffffffffe930ecbf RSI: 00007fff6b666680 RDI: 0000000000000000 RBP: 00007fff6b666680 R08: 0000000000000020 R09: 000000000000000d R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00007fff6b666770 R14: 0000000000000004 R15: 0000000000000001