From 38a81da2205f94e8a2a834b51a6b99c91fc7c2e8 Mon Sep 17 00:00:00 2001
From: Matt Helsley <matthltc@us.ibm.com>
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 <matthltc@us.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robin Green <greenrd@greenrd.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
LKML-Reference: <a134e5e392ab0204961fd1a62c84a222bf5874a9.1284407763.git.matthltc@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/arm/oprofile/common.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
(limited to 'arch/arm/oprofile/common.c')
diff --git a/arch/arm/oprofile/common.c b/arch/arm/oprofile/common.c
index 0691176..aad63e6 100644
--- a/arch/arm/oprofile/common.c
+++ b/arch/arm/oprofile/common.c
@@ -96,7 +96,7 @@ static int op_create_counter(int cpu, int event)
return ret;
pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
- cpu, -1,
+ cpu, NULL,
op_overflow_handler);
if (IS_ERR(pevent)) {
--
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