[PATCH 2/2] module: deal with the failure of complete_formation

From: Qiu, PeiyangX
Date: Fri Dec 25 2015 - 02:04:02 EST


From: Qiu Peiyang <peiyangx.qiu@xxxxxxxxx>

complete_formation might fail. kernel need clean up
ftrace records of the module.

The patch fixes it by tuning the operation sequence in
complete_formation. After complete_formation checks
verify_export_symbols, call ftrace_module_init to init
ftrace records.

Signed-off-by: Qiu Peiyang <peiyangx.qiu@xxxxxxxxx>
Signed-off-by: Zhang Yanmin <yanmin.zhang@xxxxxxxxx>
---
kernel/module.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 8f051a1..0a67c4e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3373,6 +3373,11 @@ static int complete_formation(struct module *mod, struct load_info *info)
/* This relies on module_mutex for list integrity. */
module_bug_finalize(info->hdr, info->sechdrs, mod);

+ mutex_unlock(&module_mutex);
+
+ /* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
+ ftrace_module_init(mod);
+
/* Set RO and NX regions for core */
set_section_ro_nx(mod->module_core,
mod->core_text_size,
@@ -3388,7 +3393,6 @@ static int complete_formation(struct module *mod, struct load_info *info)
/* Mark state as coming so strong_try_module_get() ignores us,
* but kallsyms etc. can see us. */
mod->state = MODULE_STATE_COMING;
- mutex_unlock(&module_mutex);

blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_COMING, mod);
@@ -3505,9 +3509,6 @@ static int load_module(struct load_info *info, const char __user *uargs,

dynamic_debug_setup(info->debug, info->num_debug);

- /* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
- ftrace_module_init(mod);
-
/* Finally it's fully formed, ready to start executing. */
err = complete_formation(mod, info);
if (err)
--
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/