• Ingo Molnar's avatar
    sched: fix kernel warning on /proc/sched_debug access · 29d7b90c
    Ingo Molnar authored
    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-g9c7c3546 #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:
    
      7cbaef9c: sched: optimize sched_clock() a bit
    
    Change the calls to cpu_clock().
    Reported-by: default avatarLuis Henriques <henrix@sapo.pt>
    29d7b90c
sched_debug.c 10.6 KB