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authorLinus Torvalds <torvalds@linux-foundation.org>2014-05-08 14:17:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-05-08 14:17:13 -0700
commitf322e262386d155c4b543f51c9939dca525a2948 (patch)
tree9b4830ee578bc9058496ec4094392414cd5112f3
parentd86561b4c7473ad43e365afdba2142b75907c9d2 (diff)
parent8058bd0faad860e75547cc5cb5d4ade016247a79 (diff)
downloadlinux-stericsson-f322e262386d155c4b543f51c9939dca525a2948.tar.gz
Merge tag 'trace-fixes-v3.15-rc4-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt: "This contains two fixes. The first is a long standing bug that causes bogus data to show up in the refcnt field of the module_refcnt tracepoint. It was introduced by a merge conflict resolution back in 2.6.35-rc days. The result should be 'refcnt = incs - decs', but instead it did 'refcnt = incs + decs'. The second fix is to a bug that was introduced in this merge window that allowed for a tracepoint funcs pointer to be used after it was freed. Moving the location of where the probes are released solved the problem" * tag 'trace-fixes-v3.15-rc4-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracepoint: Fix use of tracepoint funcs after rcu free trace: module: Maintain a valid user count
-rw-r--r--include/trace/events/module.h2
-rw-r--r--kernel/tracepoint.c4
2 files changed, 3 insertions, 3 deletions
diff --git a/include/trace/events/module.h b/include/trace/events/module.h
index ed0b2c599a64..7c5cbfe3fc49 100644
--- a/include/trace/events/module.h
+++ b/include/trace/events/module.h
@@ -80,7 +80,7 @@ DECLARE_EVENT_CLASS(module_refcnt,
TP_fast_assign(
__entry->ip = ip;
- __entry->refcnt = __this_cpu_read(mod->refptr->incs) + __this_cpu_read(mod->refptr->decs);
+ __entry->refcnt = __this_cpu_read(mod->refptr->incs) - __this_cpu_read(mod->refptr->decs);
__assign_str(name, mod->name);
),
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index ac5b23cf7212..6620e5837ce2 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -188,7 +188,6 @@ static int tracepoint_add_func(struct tracepoint *tp,
WARN_ON_ONCE(1);
return PTR_ERR(old);
}
- release_probes(old);
/*
* rcu_assign_pointer has a smp_wmb() which makes sure that the new
@@ -200,6 +199,7 @@ static int tracepoint_add_func(struct tracepoint *tp,
rcu_assign_pointer(tp->funcs, tp_funcs);
if (!static_key_enabled(&tp->key))
static_key_slow_inc(&tp->key);
+ release_probes(old);
return 0;
}
@@ -221,7 +221,6 @@ static int tracepoint_remove_func(struct tracepoint *tp,
WARN_ON_ONCE(1);
return PTR_ERR(old);
}
- release_probes(old);
if (!tp_funcs) {
/* Removed last function */
@@ -232,6 +231,7 @@ static int tracepoint_remove_func(struct tracepoint *tp,
static_key_slow_dec(&tp->key);
}
rcu_assign_pointer(tp->funcs, tp_funcs);
+ release_probes(old);
return 0;
}