On Tue, Dec 15, 2015 at 02:01:32PM +0100, Dmitry Vyukov wrote:
> Call Trace: > <IRQ> [<ffffffff810e5e38>] sched_show_task+0x148/0x250 > kernel/sched/core.c:4934 <snip> > [<ffffffff823ff46c>] apic_timer_interrupt+0x8c/0xa0 > arch/x86/entry/entry_64.S:520 > > <EOI> [< inline >] ? arch_local_irq_enable > ./arch/x86/include/asm/paravirt.h:816 > <EOI> [< inline >] ? __raw_spin_unlock_irq > include/linux/spinlock_api_smp.h:170 > <EOI> [<ffffffff823fde9e>] ? _raw_spin_unlock_irq+0x2e/0x40 > kernel/locking/spinlock.c:199 > [< inline >] ? __raw_spin_unlock_irq > include/linux/spinlock_api_smp.h:170 > [<ffffffff823fde97>] ? _raw_spin_unlock_irq+0x27/0x40 > kernel/locking/spinlock.c:199 > [<ffffffff8119c8bb>] perf_install_in_context+0x6b/0xf0 > kernel/events/core.c:2173 > [<ffffffff811a492c>] SYSC_perf_event_open+0x63c/0xe40 > kernel/events/core.c:8565 > [<ffffffff811a7739>] SyS_perf_event_open+0x9/0x10 kernel/events/core.c:8261 > [<ffffffff823fe676>] entry_SYSCALL_64_fastpath+0x16/0x7a > arch/x86/entry/entry_64.S:185 So this looks like its stuck in the retry loop in perf_install_in_context(). We do the raw_spin_unlock_irq(), which allows the above watchdog interrupt to happen, but make no progress. This means the task_function_call() thing keeps failing, which is extremely unlikely. Let me have a play with your test-case to see if it reproduces. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
