From 38a81da2205f94e8a2a834b51a6b99c91fc7c2e8 Mon Sep 17 00:00:00 2001 From: Matt Helsley Date: Mon, 13 Sep 2010 13:01:20 -0700 Subject: perf events: Clean up pid passing The kernel perf event creation path shouldn't use find_task_by_vpid() because a vpid exists in a specific namespace. find_task_by_vpid() uses current's pid namespace which isn't always the correct namespace to use for the vpid in all the places perf_event_create_kernel_counter() (and thus find_get_context()) is called. The goal is to clean up pid namespace handling and prevent bugs like: https://bugzilla.kernel.org/show_bug.cgi?id=17281 Instead of using pids switch find_get_context() to use task struct pointers directly. The syscall is responsible for resolving the pid to a task struct. This moves the pid namespace resolution into the syscall much like every other syscall that takes pid parameters. Signed-off-by: Matt Helsley Signed-off-by: Peter Zijlstra Cc: Robin Green Cc: Prasad Cc: Arnaldo Carvalho de Melo Cc: Steven Rostedt Cc: Will Deacon Cc: Mahesh Salgaonkar LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/watchdog.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/watchdog.c') diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 89eadbb..dc8e168 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -358,7 +358,7 @@ static int watchdog_nmi_enable(int cpu) /* Try to register using hardware perf events */ wd_attr = &wd_hw_attr; wd_attr->sample_period = hw_nmi_get_sample_period(); - event = perf_event_create_kernel_counter(wd_attr, cpu, -1, watchdog_overflow_callback); + event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback); if (!IS_ERR(event)) { printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n"); goto out_save; -- cgit v1.1