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Subject[PATCH 3/4] ftrace: No return value for ftrace_process_locs
Date
The return value of ftrace_process_locs is never checked. The function
tries to update as many calls as possible and in case of error there's
either warning output or ftrace_bug call.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
---
kernel/trace/ftrace.c | 37 ++++++++++++++++---------------------
1 files changed, 16 insertions(+), 21 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b3ceecd..e67f5b3 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1930,7 +1930,7 @@ static int ops_traces_mod(struct ftrace_ops *ops)
return ftrace_hash_empty(hash);
}

-static int ftrace_update_code(struct module *mod)
+static void ftrace_update_code(struct module *mod)
{
struct ftrace_page *pg;
struct dyn_ftrace *p;
@@ -1959,7 +1959,7 @@ static int ftrace_update_code(struct module *mod)
for (i = 0; i < pg->index; i++) {
/* If something went wrong, bail without enabling anything */
if (unlikely(ftrace_disabled))
- return -1;
+ return;

p = &pg->records[i];
p->flags = ref;
@@ -1968,8 +1968,8 @@ static int ftrace_update_code(struct module *mod)
* Do the initial record conversion from mcount jump
* to the NOP instructions.
*/
- if (!ftrace_code_disable(mod, p))
- break;
+ if (WARN_ON_ONCE(!ftrace_code_disable(mod, p)))
+ return;

cnt++;

@@ -1992,7 +1992,6 @@ static int ftrace_update_code(struct module *mod)

ftrace_new_pgs = NULL;
ftrace_update_tot_cnt += cnt;
- return 0;
}

static int ftrace_allocate_records(struct ftrace_page *pg, int count)
@@ -2041,11 +2040,11 @@ ftrace_allocate_pages(unsigned long num_to_init)
int cnt;

if (!num_to_init)
- return 0;
+ return NULL;

start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
if (!pg)
- return NULL;
+ goto out;

/*
* Try to allocate as much as possible in one continues
@@ -2078,6 +2077,7 @@ ftrace_allocate_pages(unsigned long num_to_init)
kfree(pg);
pg = start_pg;
}
+ out:
pr_info("ftrace: FAILED to allocate memory for functions\n");
return NULL;
}
@@ -3589,25 +3589,23 @@ static void ftrace_swap_recs(void *a, void *b, int size)
*recb = t;
}

-static int ftrace_process_locs(struct module *mod,
- unsigned long *start,
- unsigned long *end)
+static void ftrace_process_locs(struct module *mod,
+ unsigned long *start,
+ unsigned long *end)
{
struct ftrace_page *pg;
unsigned long count;
unsigned long *p;
unsigned long addr;
unsigned long flags = 0; /* Shut up gcc */
- int ret = -ENOMEM;

count = end - start;
-
if (!count)
- return 0;
+ return;

pg = ftrace_allocate_pages(count);
if (!pg)
- return -ENOMEM;
+ return;

mutex_lock(&ftrace_lock);

@@ -3621,7 +3619,7 @@ static int ftrace_process_locs(struct module *mod,
/* First initialization */
ftrace_pages = ftrace_pages_start = pg;
} else {
- if (!ftrace_pages)
+ if (!WARN_ON_ONCE(ftrace_pages))
goto out;

if (WARN_ON(ftrace_pages->next)) {
@@ -3670,11 +3668,8 @@ static int ftrace_process_locs(struct module *mod,
ftrace_update_code(mod);
if (!mod)
local_irq_restore(flags);
- ret = 0;
out:
mutex_unlock(&ftrace_lock);
-
- return ret;
}

#ifdef CONFIG_MODULES
@@ -3789,9 +3784,9 @@ void __init ftrace_init(void)

last_ftrace_enabled = ftrace_enabled = 1;

- ret = ftrace_process_locs(NULL,
- __start_mcount_loc,
- __stop_mcount_loc);
+ ftrace_process_locs(NULL,
+ __start_mcount_loc,
+ __stop_mcount_loc);

ret = register_module_notifier(&ftrace_module_nb);
if (ret)
--
1.7.1


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