Messages in this thread | | | Date | Thu, 29 Jul 2021 12:19:57 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH][RFC] sched/cpuacct: Fix cpuacct charge |
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On Tue, Jul 20, 2021 at 02:04:41PM +0800, Li RongQing wrote: > get_irq_regs only work for current running cpu, but the task, whose > cpuacct will be charged, maybe run different cpu, like Cpu 2 wake > up a kernel thread to CPU 3, cause CPU 3 task are charged with the > following stack > > cpuacct_charge+0xd8/0x100 > update_curr+0xe1/0x1e0 > enqueue_entity+0x144/0x6e0 > enqueue_task_fair+0x93/0x900 > ttwu_do_activate+0x4b/0x90 > try_to_wake_up+0x20b/0x530 > ? update_dl_rq_load_avg+0x10f/0x210 > swake_up_locked.part.1+0x13/0x40 > swake_up_one+0x27/0x40 > rcu_process_callbacks+0x484/0x4f0 > ? run_rebalance_domains_bt+0x5a/0x180 > __do_softirq+0xe3/0x308 > irq_exit+0xf0/0x100 > smp_apic_timer_interrupt+0x74/0x160 > apic_timer_interrupt+0xf/0x20 > </IRQ> > RIP: 0033:0x456947 > > so define a get_irq_regs_cpu which returns the required cpu irq registers > > BUT it should be not safe, and do not know what it should be like in MIPS? > > Fixes: dbe9337109c2 "(sched/cpuacct: Fix charge cpuacct.usage_sys)" > Co-developed-by: Zhao Jie <zhaojie17@baidu.com> > Signed-off-by: Zhao Jie <zhaojie17@baidu.com> > Signed-off-by: Li RongQing <lirongqing@baidu.com> > --- > include/asm-generic/irq_regs.h | 5 +++++ > kernel/sched/cpuacct.c | 3 ++- > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/include/asm-generic/irq_regs.h b/include/asm-generic/irq_regs.h > index 2e7c6e8..93e2579 100644 > --- a/include/asm-generic/irq_regs.h > +++ b/include/asm-generic/irq_regs.h > @@ -21,6 +21,11 @@ static inline struct pt_regs *get_irq_regs(void) > return __this_cpu_read(__irq_regs); > } > > +static inline struct pt_regs *get_irq_regs_cpu(int cpu) > +{ > + return per_cpu(__irq_regs, cpu); > +}
This primitive just cannot be right... it'll get you some random data.
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