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ksym_tracer: Fix to make the tracer work 

ksym tracer doesn't work:

 # echo tasklist_lock:rw- > ksym_trace_filter
 -bash: echo: write error: No such device

It's because we pass to perf_event_create_kernel_counter()
a cpu number which is not present.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B3AF19E.1010201@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Li Zefan 2009-12-30 14:22:22 +08:00 committed by Ingo Molnar
parent 40892367bc
commit 88f7a890d7
2 changed files with 7 additions and 4 deletions
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10
kernel/hw_breakpoint.c
View File

@ -40,6 +40,7 @@
#include <linux/percpu.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/hw_breakpoint.h>
@ -388,7 +389,8 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr,
if (!cpu_events)
return ERR_PTR(-ENOMEM);
for_each_possible_cpu(cpu) {
get_online_cpus();
for_each_online_cpu(cpu) {
pevent = per_cpu_ptr(cpu_events, cpu);
bp = perf_event_create_kernel_counter(attr, cpu, -1, triggered);
@ -399,18 +401,20 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr,
goto fail;
}
}
put_online_cpus();
return cpu_events;
fail:
for_each_possible_cpu(cpu) {
for_each_online_cpu(cpu) {
pevent = per_cpu_ptr(cpu_events, cpu);
if (IS_ERR(*pevent))
break;
unregister_hw_breakpoint(*pevent);
}
put_online_cpus();
free_percpu(cpu_events);
/* return the error if any */
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint);

1
kernel/trace/trace_ksym.c
View File

@ -197,7 +197,6 @@ int process_new_ksym_entry(char *ksymname, int op, unsigned long addr)
entry->attr.bp_addr = addr;
entry->attr.bp_len = HW_BREAKPOINT_LEN_4;
ret = -EAGAIN;
entry->ksym_hbp = register_wide_hw_breakpoint(&entry->attr,
ksym_hbp_handler);