Re: [tracepoint] 01edfaf177: WARNING:at_kernel/static_call.c:#__static_call_update

Peter Zijlstra
2020-05-15T17:13:57Z

On Wed, May 13, 2020 at 04:48:11PM +0800, kernel test robot wrote:

> commit: 01edfaf177311fba9941254793431d2044b00fd7 ("[PATCH v4 12/18] tracepoint: Optimize using static_call()")
> url: https://github.com/0day-ci/linux/commits/Peter-Zijlstra/Add-static_call/20200502-045208

*groan*, so I would really rather you grab patches from by git tree than
suck random crap from lkml like this :/

Anyway, I _suspect_ this is fixed in a later patch that initializes
static_call earlier, but I can't tell for sure, because I really
don't know what to do to reproduce this.

> [ 1.990628] WARNING: CPU: 0 PID: 0 at kernel/static_call.c:113 __static_call_update+0x83/0x29c
> [ 1.990660] Modules linked in:
> [ 1.990703] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.7.0-rc3-next-20200501-00012-g01edfaf177311f #1
> [ 1.990742] RIP: 0010:__static_call_update+0x83/0x29c
> [ 1.990781] Code: 4c 89 f2 48 ff 05 d1 9d 83 06 e8 8e 09 d2 ff 48 ff 05 d5 9d 83 06 80 3d 8e a2 83 06 00 0f 85 f3 01 00 00 48 ff 05 c9 9d 83 06 <0f> 0b 48 ff 05 c8 9d 83 06 48 ff 05 c9 9d 83 06 e9 b0 01 00 00 48
> [ 1.990814] RSP: 0000:ffffffff83c07cf8 EFLAGS: 00010002
> [ 1.990850] RAX: 0000000000000000 RBX: ffffffff86682620 RCX: 0000000000000000
> [ 1.990884] RDX: fffffbfff0780f87 RSI: ffffffff83c918c0 RDI: fffffbfff0780f93
> [ 1.990916] RBP: ffffffff812943ec R08: fffffbfff07e3551 R09: fffffbfff07e3551
> [ 1.990950] R10: ffffffff83f1aa87 R11: 0000000000000001 R12: ffffffff83f6f0c0
> [ 1.990982] R13: 00000000ffffffff R14: ffffffff812943ec R15: ffffffff812943ec
> [ 1.991017] FS: 0000000000000000(0000) GS:ffff8881e8000000(0000) knlGS:0000000000000000
> [ 1.991049] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 1.991081] CR2: ffff88823ffff000 CR3: 0000000003c78000 CR4: 00000000000006b0
> [ 1.991119] Call Trace:
> [ 1.991164] ? __SCT__tp_func_sched_waking+0x8/0x8
> [ 1.991202] ? allocate_probes+0x2d/0x4d
> [ 1.991250] ? probe_sched_switch+0x4f/0x4f
> [ 1.991286] ? __SCT__tp_func_sched_waking+0x8/0x8
> [ 1.991331] ? probe_sched_switch+0x4f/0x4f
> [ 1.991366] tracepoint_update_call+0x6d/0x79
> [ 1.991416] tracepoint_probe_register_prio+0x337/0x47f
> [ 1.991499] tracepoint_probe_register+0x16/0x1e
> [ 1.991538] tracing_start_sched_switch+0xc3/0x1ba
> [ 1.991627] tracing_start_cmdline_record+0x11/0x19
> [ 1.991664] trace_printk_start_comm+0x1c/0x24
> [ 1.991725] trace_event_init+0x1b8/0x20a
> [ 1.991775] trace_init+0xc/0x14
> [ 1.991809] start_kernel+0x8ed/0xe78
> [ 1.991862] ? thread_stack_cache_init+0xd/0xd
> [ 1.991905] ? __early_make_pgtable+0x1b9/0x204
> [ 1.991963] ? early_make_pgtable+0x27/0x2f
> [ 1.992000] ? early_idt_handler_common+0x35/0x4c
> [ 1.992131] x86_64_start_reservations+0x42/0x4a
> [ 1.992170] x86_64_start_kernel+0xe1/0xea
> [ 1.992216] secondary_startup_64+0xa4/0xb0
> [ 1.992336] irq event stamp: 0
> [ 1.992371] hardirqs last enabled at (0): [<0000000000000000>] 0x0
> [ 1.992403] hardirqs last disabled at (0): [<0000000000000000>] 0x0
> [ 1.992437] softirqs last enabled at (0): [<0000000000000000>] 0x0
> [ 1.992469] softirqs last disabled at (0): [<0000000000000000>] 0x0
> [ 1.992562] ---[ end trace 15ea566c311b9aea ]---
>
>
> To reproduce:
>
> # build kernel
> cd linux
> cp config-5.7.0-rc3-next-20200501-00012-g01edfaf177311f .config
> make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage
>
> git clone https://github.com/intel/lkp-tests.git
> cd lkp-tests
> bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email

Because ^ is just not going to happen. And from the provided information
I cannot decipher what it takes to trigger this.

Also, your dmesg had the trace_printk() splat in, and that is certainly
not from these patches.