mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 01:10:04 +00:00
ksym_tracer: Fix race when incrementing count
We are under rcu read section but not holding the write lock, so count++ is not atomic. Use atomic64_t instead. 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: <4B3AF1EC.9010608@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
parent
3d13ec2efd
commit
e6d9491bf8
1 changed files with 7 additions and 5 deletions
|
@ -32,6 +32,8 @@
|
|||
#include <linux/hw_breakpoint.h>
|
||||
#include <asm/hw_breakpoint.h>
|
||||
|
||||
#include <asm/atomic.h>
|
||||
|
||||
/*
|
||||
* For now, let us restrict the no. of symbols traced simultaneously to number
|
||||
* of available hardware breakpoint registers.
|
||||
|
@ -44,7 +46,7 @@ struct trace_ksym {
|
|||
struct perf_event **ksym_hbp;
|
||||
struct perf_event_attr attr;
|
||||
#ifdef CONFIG_PROFILE_KSYM_TRACER
|
||||
unsigned long counter;
|
||||
atomic64_t counter;
|
||||
#endif
|
||||
struct hlist_node ksym_hlist;
|
||||
};
|
||||
|
@ -69,9 +71,8 @@ void ksym_collect_stats(unsigned long hbp_hit_addr)
|
|||
|
||||
rcu_read_lock();
|
||||
hlist_for_each_entry_rcu(entry, node, &ksym_filter_head, ksym_hlist) {
|
||||
if ((entry->attr.bp_addr == hbp_hit_addr) &&
|
||||
(entry->counter <= MAX_UL_INT)) {
|
||||
entry->counter++;
|
||||
if (entry->attr.bp_addr == hbp_hit_addr) {
|
||||
atomic64_inc(&entry->counter);
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
@ -501,7 +502,8 @@ static int ksym_tracer_stat_show(struct seq_file *m, void *v)
|
|||
seq_printf(m, " %-36s", fn_name);
|
||||
else
|
||||
seq_printf(m, " %-36s", "<NA>");
|
||||
seq_printf(m, " %15lu\n", entry->counter);
|
||||
seq_printf(m, " %15llu\n",
|
||||
(unsigned long long)atomic64_read(&entry->counter));
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue