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Date: Mon, 5 Dec 2011 18:22:48 +0100
From: Jiri Olsa <jolsa@...hat.com>
To: rostedt@...dmis.org, fweisbec@...il.com, mingo@...hat.com,
paulus@...ba.org, acme@...stprotocols.net, a.p.zijlstra@...llo.nl
Cc: linux-kernel@...r.kernel.org, aarapov@...hat.com,
Jiri Olsa <jolsa@...hat.com>
Subject: [PATCHv2 02/10] ftrace: Change mcount call replacement logic
The current logic of updating calls is to do the mcount replacement
only when ftrace_ops is being registered. When ftrace_ops is being
unregistered then only in case it was the last registered ftrace_ops,
all calls are disabled.
This is an issue when ftrace_ops without FTRACE_OPS_FL_GLOBAL flag
is being unregistered, because all the functions stays enabled
and thus inherrited by global_ops, like in following scenario:
- set restricting global filter
- enable function trace
- register/unregister ftrace_ops with flags != FTRACE_OPS_FL_GLOBAL
and with no filter
Now the global_ops will get by all the functions regardless the
global_ops filter. So we need all functions that where enabled via
this ftrace_ops and are not part of global filter to be disabled.
Note, currently if there are only global ftrace_ops registered,
there's no filter hash check and the filter is represented only
by enabled records.
Changing the ftrace_shutdown logic to ensure the replacement
is called for each ftrace_ops being unregistered.
Also changing FTRACE_ENABLE_CALLS into FTRACE_UPDATE_CALLS
calls which seems more suitable now.
Signed-off-by: Jiri Olsa <jolsa@...hat.com>
---
kernel/trace/ftrace.c | 27 +++++++++++++--------------
1 files changed, 13 insertions(+), 14 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index c6d0293..b79ab33 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -948,7 +948,7 @@ struct ftrace_func_probe {
};
enum {
- FTRACE_ENABLE_CALLS = (1 << 0),
+ FTRACE_UPDATE_CALLS = (1 << 0),
FTRACE_DISABLE_CALLS = (1 << 1),
FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
FTRACE_START_FUNC_RET = (1 << 3),
@@ -1520,7 +1520,7 @@ int ftrace_text_reserved(void *start, void *end)
static int
-__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
+__ftrace_replace_code(struct dyn_ftrace *rec, int update)
{
unsigned long ftrace_addr;
unsigned long flag = 0UL;
@@ -1528,17 +1528,17 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
ftrace_addr = (unsigned long)FTRACE_ADDR;
/*
- * If we are enabling tracing:
+ * If we are updating calls:
*
* If the record has a ref count, then we need to enable it
* because someone is using it.
*
* Otherwise we make sure its disabled.
*
- * If we are disabling tracing, then disable all records that
+ * If we are disabling calls, then disable all records that
* are enabled.
*/
- if (enable && (rec->flags & ~FTRACE_FL_MASK))
+ if (update && (rec->flags & ~FTRACE_FL_MASK))
flag = FTRACE_FL_ENABLED;
/* If the state of this record hasn't changed, then do nothing */
@@ -1554,7 +1554,7 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
return ftrace_make_nop(NULL, rec, ftrace_addr);
}
-static void ftrace_replace_code(int enable)
+static void ftrace_replace_code(int update)
{
struct dyn_ftrace *rec;
struct ftrace_page *pg;
@@ -1568,7 +1568,7 @@ static void ftrace_replace_code(int enable)
if (rec->flags & FTRACE_FL_FREE)
continue;
- failed = __ftrace_replace_code(rec, enable);
+ failed = __ftrace_replace_code(rec, update);
if (failed) {
ftrace_bug(failed, rec->ip);
/* Stop processing */
@@ -1624,7 +1624,7 @@ static int __ftrace_modify_code(void *data)
*/
function_trace_stop++;
- if (*command & FTRACE_ENABLE_CALLS)
+ if (*command & FTRACE_UPDATE_CALLS)
ftrace_replace_code(1);
else if (*command & FTRACE_DISABLE_CALLS)
ftrace_replace_code(0);
@@ -1692,7 +1692,7 @@ static int ftrace_startup(struct ftrace_ops *ops, int command)
return -ENODEV;
ftrace_start_up++;
- command |= FTRACE_ENABLE_CALLS;
+ command |= FTRACE_UPDATE_CALLS;
/* ops marked global share the filter hashes */
if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
@@ -1744,8 +1744,7 @@ static void ftrace_shutdown(struct ftrace_ops *ops, int command)
if (ops != &global_ops || !global_start_up)
ops->flags &= ~FTRACE_OPS_FL_ENABLED;
- if (!ftrace_start_up)
- command |= FTRACE_DISABLE_CALLS;
+ command |= FTRACE_UPDATE_CALLS;
if (saved_ftrace_func != ftrace_trace_function) {
saved_ftrace_func = ftrace_trace_function;
@@ -1767,7 +1766,7 @@ static void ftrace_startup_sysctl(void)
saved_ftrace_func = NULL;
/* ftrace_start_up is true if we want ftrace running */
if (ftrace_start_up)
- ftrace_run_update_code(FTRACE_ENABLE_CALLS);
+ ftrace_run_update_code(FTRACE_UPDATE_CALLS);
}
static void ftrace_shutdown_sysctl(void)
@@ -2920,7 +2919,7 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
ret = ftrace_hash_move(ops, enable, orig_hash, hash);
if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
&& ftrace_enabled)
- ftrace_run_update_code(FTRACE_ENABLE_CALLS);
+ ftrace_run_update_code(FTRACE_UPDATE_CALLS);
mutex_unlock(&ftrace_lock);
@@ -3108,7 +3107,7 @@ ftrace_regex_release(struct inode *inode, struct file *file)
orig_hash, iter->hash);
if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
&& ftrace_enabled)
- ftrace_run_update_code(FTRACE_ENABLE_CALLS);
+ ftrace_run_update_code(FTRACE_UPDATE_CALLS);
mutex_unlock(&ftrace_lock);
}
--
1.7.1
--
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