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| author | Ingo Molnar <mingo@elte.hu> | 2008-11-16 08:07:15 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-11-16 08:07:15 +0100 |
| commit | 29d7b90c15035741d15421b36000509212b3e135 (patch) | |
| tree | a9978411950af9c4dbebcc82a944fef35a58f209 /kernel | |
| parent | 2fe401e38602e853e01376cdb670b0bc4d526a6d (diff) | |
| download | lwn-29d7b90c15035741d15421b36000509212b3e135.tar.gz lwn-29d7b90c15035741d15421b36000509212b3e135.zip | |
sched: fix kernel warning on /proc/sched_debug access
Luis Henriques reported that with CONFIG_PREEMPT=y + CONFIG_PREEMPT_DEBUG=y +
CONFIG_SCHED_DEBUG=y + CONFIG_LATENCYTOP=y enabled, the following warning
triggers when using latencytop:
> [ 775.663239] BUG: using smp_processor_id() in preemptible [00000000] code: latencytop/6585
> [ 775.663303] caller is native_sched_clock+0x3a/0x80
> [ 775.663314] Pid: 6585, comm: latencytop Tainted: G W 2.6.28-rc4-00355-g9c7c354 #1
> [ 775.663322] Call Trace:
> [ 775.663343] [<ffffffff803a94e4>] debug_smp_processor_id+0xe4/0xf0
> [ 775.663356] [<ffffffff80213f7a>] native_sched_clock+0x3a/0x80
> [ 775.663368] [<ffffffff80213e19>] sched_clock+0x9/0x10
> [ 775.663381] [<ffffffff8024550d>] proc_sched_show_task+0x8bd/0x10e0
> [ 775.663395] [<ffffffff8034466e>] sched_show+0x3e/0x80
> [ 775.663408] [<ffffffff8031039b>] seq_read+0xdb/0x350
> [ 775.663421] [<ffffffff80368776>] ? security_file_permission+0x16/0x20
> [ 775.663435] [<ffffffff802f4198>] vfs_read+0xc8/0x170
> [ 775.663447] [<ffffffff802f4335>] sys_read+0x55/0x90
> [ 775.663460] [<ffffffff8020c67a>] system_call_fastpath+0x16/0x1b
> ...
This breakage was caused by me via:
7cbaef9: sched: optimize sched_clock() a bit
Change the calls to cpu_clock().
Reported-by: Luis Henriques <henrix@sapo.pt>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched_debug.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index 48ecc51e7701..26ed8e3d1c15 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -423,10 +423,11 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m) #undef __P { + unsigned int this_cpu = raw_smp_processor_id(); u64 t0, t1; - t0 = sched_clock(); - t1 = sched_clock(); + t0 = cpu_clock(this_cpu); + t1 = cpu_clock(this_cpu); SEQ_printf(m, "%-35s:%21Ld\n", "clock-delta", (long long)(t1-t0)); } |