On Thu, Apr 19, 2018 at 08:22:24AM +0200, Geert Uytterhoeven wrote: >Hi Fengguang, > >On Thu, Apr 19, 2018 at 4:50 AM, Fengguang Wu wrote: >> FYI this happens in mainline kernel 4.17.0-rc1. >> It dates back to v4.14-rc1 , perhaps since the test was introduced. >> >> It occurs in 1 out of 1 boots. > >I guess the test just takes too long, causing a panic if >BOOTPARAM_HUNG_TASK_PANIC=y? That does the trick of saving test time. ;) Another option is to add cond_resched(), will that be feasible? Thanks, Fengguang >> [ 83.615461] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 246) >> [ 83.627616] io scheduler noop registered >> [ 83.634396] io scheduler deadline registered (default) >> [ 83.643012] io scheduler mq-deadline registered (default) >> [ 83.652509] io scheduler bfq registered >> [ 108.580122] watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [swapper/0:1] >> [ 108.580122] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.17.0-rc1 #210 >> [ 108.580122] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 >> [ 108.580122] RIP: 0010:check_kcov_mode+0x24/0x37: >> __read_once_size at include/linux/compiler.h:188 (discriminator 1) >> (inlined by) check_kcov_mode at kernel/kcov.c:69 (discriminator 1) >> [ 108.580122] RSP: 0000:ffff88000fd43e48 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 >> [ 108.580122] RAX: 0000000000000000 RBX: ffff88000fd3e000 RCX: 0000000000000000 >> [ 108.580122] RDX: 0000000000000000 RSI: ffff88000fd3e000 RDI: 0000000000000002 >> [ 108.580122] RBP: ffffffff853b9f96 R08: 00000000014000c0 R09: 00000000ffffffff >> [ 108.580122] R10: ffff88000fd3e000 R11: 0000000000000002 R12: ffff88001a6c0458 >> [ 108.580122] R13: 0000000000000011 R14: ffff88001a6c0530 R15: 00000000a1a1a1a1 >> [ 108.580122] FS: 0000000000000000(0000) GS:ffff88001f600000(0000) knlGS:0000000000000000 >> [ 108.580122] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [ 108.580122] CR2: 0000000000000000 CR3: 0000000003c6a000 CR4: 00000000000006b0 >> [ 108.580122] Call Trace: >> [ 108.580122] __sanitizer_cov_trace_pc+0x2b/0x66: >> __sanitizer_cov_trace_pc at kernel/kcov.c:101 >> [ 108.580122] string_selftest_init+0x25e/0x5c0: >> memset32_selftest at lib/test_string.c:60 >> (inlined by) string_selftest_init at lib/test_string.c:124 >> [ 108.580122] ? prandom_reseed+0x52/0x52: >> string_selftest_init at lib/test_string.c:115 >> [ 108.580122] do_one_initcall+0x18e/0x3df: >> do_one_initcall at init/main.c:883 >> [ 108.580122] ? check_kcov_mode+0x5/0x37: >> check_kcov_mode at kernel/kcov.c:60 >> [ 108.580122] ? __sanitizer_cov_trace_pc+0x2b/0x66: >> __sanitizer_cov_trace_pc at kernel/kcov.c:101 >> [ 108.580122] ? check_kcov_mode+0x5/0x37: >> check_kcov_mode at kernel/kcov.c:60 >> [ 108.580122] kernel_init_freeable+0x250/0x3a5: >> do_initcall_level at init/main.c:951 >> (inlined by) do_initcalls at init/main.c:959 >> (inlined by) do_basic_setup at init/main.c:977 >> (inlined by) kernel_init_freeable at init/main.c:1127 >> [ 108.580122] ? rest_init+0x13a/0x13a: >> kernel_init at init/main.c:1050 >> [ 108.580122] kernel_init+0x17/0x218: >> kernel_init at init/main.c:1053 >> [ 108.580122] ? rest_init+0x13a/0x13a: >> kernel_init at init/main.c:1050 >> [ 108.580122] ret_from_fork+0x35/0x40: >> ret_from_fork at arch/x86/entry/entry_64.S:418 >> [ 108.580122] Code: 41 5c 41 5d 41 5e c3 e8 e8 c6 a3 01 48 ff 05 71 33 fd 04 31 c0 65 8b 15 78 00 e5 7e 81 e2 00 01 1f 00 75 19 48 ff 05 61 33 fd 04 <8b> 86 18 1c 00 00 39 c7 0f 94 c0 48 ff 05 57 33 fd 04 c3 e8 b1 >> [ 108.580122] Kernel panic - not syncing: softlockup: hung tasks >> [ 108.580122] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G L 4.17.0-rc1 #210 >> [ 108.580122] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 >> [ 108.580122] Call Trace: >> [ 108.580122] >> [ 108.580122] dump_stack+0xf3/0x135: >> __dump_stack at lib/dump_stack.c:77 >> (inlined by) dump_stack at lib/dump_stack.c:113 >> [ 108.580122] panic+0x173/0x440: >> panic at kernel/panic.c:195 >> [ 108.580122] watchdog_timer_fn+0x343/0x382: >> watchdog_timer_fn at kernel/watchdog.c:444 >> [ 108.580122] __hrtimer_run_queues+0x2a0/0x4c3: >> __run_hrtimer at kernel/time/hrtimer.c:1386 >> (inlined by) __hrtimer_run_queues at kernel/time/hrtimer.c:1448 >> [ 108.580122] hrtimer_run_queues+0xcb/0xed: >> hrtimer_run_queues at kernel/time/hrtimer.c:1621 >> [ 108.580122] run_local_timers+0x2d/0x85: >> run_local_timers at kernel/time/timer.c:1704 >> [ 108.580122] update_process_times+0x30/0x7e: >> update_process_times at kernel/time/timer.c:1636 >> [ 108.580122] tick_nohz_handler+0x141/0x19a: >> tick_sched_handle at kernel/time/tick-sched.c:173 >> (inlined by) tick_nohz_handler at kernel/time/tick-sched.c:1182 >> [ 108.580122] smp_apic_timer_interrupt+0x1a5/0x2c4: >> local_apic_timer_interrupt at arch/x86/kernel/apic/apic.c:1025 >> (inlined by) smp_apic_timer_interrupt at arch/x86/kernel/apic/apic.c:1050 >> [ 108.580122] apic_timer_interrupt+0xf/0x20: >> apic_timer_interrupt at arch/x86/entry/entry_64.S:863 >> [ 108.580122] >> [ 108.580122] RIP: 0010:check_kcov_mode+0x24/0x37: >> __read_once_size at include/linux/compiler.h:188 (discriminator 1) >> (inlined by) check_kcov_mode at kernel/kcov.c:69 (discriminator 1) >> [ 108.580122] RSP: 0000:ffff88000fd43e48 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 >> [ 108.580122] RAX: 0000000000000000 RBX: ffff88000fd3e000 RCX: 0000000000000000 >> [ 108.580122] RDX: 0000000000000000 RSI: ffff88000fd3e000 RDI: 0000000000000002 >> [ 108.580122] RBP: ffffffff853b9f96 R08: 00000000014000c0 R09: 00000000ffffffff >> [ 108.580122] R10: ffff88000fd3e000 R11: 0000000000000002 R12: ffff88001a6c0458 >> [ 108.580122] R13: 0000000000000011 R14: ffff88001a6c0530 R15: 00000000a1a1a1a1 >> [ 108.580122] ? string_selftest_init+0x25e/0x5c0: >> memset32_selftest at lib/test_string.c:60 >> (inlined by) string_selftest_init at lib/test_string.c:124 >> [ 108.580122] ? check_kcov_mode+0x5/0x37: >> check_kcov_mode at kernel/kcov.c:60 >> [ 108.580122] __sanitizer_cov_trace_pc+0x2b/0x66: >> __sanitizer_cov_trace_pc at kernel/kcov.c:101 >> [ 108.580122] string_selftest_init+0x25e/0x5c0: >> memset32_selftest at lib/test_string.c:60 >> (inlined by) string_selftest_init at lib/test_string.c:124 >> [ 108.580122] ? prandom_reseed+0x52/0x52: >> string_selftest_init at lib/test_string.c:115 >> [ 108.580122] do_one_initcall+0x18e/0x3df: >> do_one_initcall at init/main.c:883 >> [ 108.580122] ? check_kcov_mode+0x5/0x37: >> check_kcov_mode at kernel/kcov.c:60 >> [ 108.580122] ? __sanitizer_cov_trace_pc+0x2b/0x66: >> __sanitizer_cov_trace_pc at kernel/kcov.c:101 >> [ 108.580122] ? check_kcov_mode+0x5/0x37: >> check_kcov_mode at kernel/kcov.c:60 >> [ 108.580122] kernel_init_freeable+0x250/0x3a5: >> do_initcall_level at init/main.c:951 >> (inlined by) do_initcalls at init/main.c:959 >> (inlined by) do_basic_setup at init/main.c:977 >> (inlined by) kernel_init_freeable at init/main.c:1127 >> [ 108.580122] ? rest_init+0x13a/0x13a: >> kernel_init at init/main.c:1050 >> [ 108.580122] kernel_init+0x17/0x218: >> kernel_init at init/main.c:1053 >> [ 108.580122] ? rest_init+0x13a/0x13a: >> kernel_init at init/main.c:1050 >> [ 108.580122] ret_from_fork+0x35/0x40: >> ret_from_fork at arch/x86/entry/entry_64.S:418 >> [ 108.580122] Kernel Offset: disabled >> >> Attached the full dmesg, kconfig and reproduce scripts. > >Gr{oetje,eeting}s, > > Geert > >-- >Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > >In personal conversations with technical people, I call myself a hacker. But >when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds >