[FIX] remove mutex and dput() functions from atomic context

Using mutex in __check_if_instrumented() called from probe handler
leads to BUG "sleeping function called from invalid context",
because probe handler calls from atomic context.

Also we cannot use dput() in atomic context.

Change-Id: I69052c0749f3734e7d4eabf07656a40e4a8f963e
Signed-off-by: Anatolii Nikulin <nikulin.a@samsung.com>

diff --git a/preload/preload_control.c b/preload/preload_control.c
index 08d922e..5b41e32 100644 (file)
--- a/preload/preload_control.c
+++ b/preload/preload_control.c
@@ -1,6 +1,6 @@
 #include <linux/mm.h>
 #include <linux/slab.h>
-#include <linux/rwsem.h>
+#include <linux/spinlock.h>
 #include <linux/limits.h>
 #include <linux/list.h>
 
@@ -19,7 +19,7 @@ struct bin_desc {
 };
 
 static LIST_HEAD(target_binaries_list);
-static DECLARE_RWSEM(target_binaries_lock);
+static DEFINE_RWLOCK(target_binaries_lock);
 static int target_binaries_cnt = 0;
 
 static inline struct task_struct *__get_task_struct(void)
@@ -59,14 +59,21 @@ static void __free_target_binary(struct bin_desc *p)
 static void __free_target_binaries(void)
 {
        struct bin_desc *p, *n;
+       struct list_head rm_head;
 
-       down_write(&target_binaries_lock);
+       INIT_LIST_HEAD(&rm_head);
+       write_lock(&target_binaries_lock);
        list_for_each_entry_safe(p, n, &target_binaries_list, list) {
+               list_move(&p->list, &rm_head);
+       }
+       target_binaries_cnt = 0;
+       write_unlock(&target_binaries_lock);
+
+       list_for_each_entry_safe(p, n, &rm_head, list) {
                list_del(&p->list);
+               put_dentry(p->dentry);
                __free_target_binary(p);
        }
-       target_binaries_cnt = 0;
-       up_write(&target_binaries_lock);
 }
 
 static bool __check_dentry_already_exist(struct dentry *dentry)
@@ -74,7 +81,7 @@ static bool __check_dentry_already_exist(struct dentry *dentry)
        struct bin_desc *p;
        bool ret = false;
 
-       down_read(&target_binaries_lock);
+       read_lock(&target_binaries_lock);
        list_for_each_entry(p, &target_binaries_list, list) {
                if (p->dentry == dentry) {
                        ret = true;
@@ -82,9 +89,9 @@ static bool __check_dentry_already_exist(struct dentry *dentry)
                }
        }
 out:
-       up_read(&target_binaries_lock);
+       read_unlock(&target_binaries_lock);
 
-       return false;
+       return ret;
 }
 
 static int __add_target_binary(struct dentry *dentry, char *filename)
@@ -106,10 +113,10 @@ static int __add_target_binary(struct dentry *dentry, char *filename)
        if (!p)
                return -ENOMEM;
 
-       down_write(&target_binaries_lock);
+       write_lock(&target_binaries_lock);
        list_add_tail(&p->list, &target_binaries_list);
        target_binaries_cnt++;
-       up_write(&target_binaries_lock);
+       write_unlock(&target_binaries_lock);
 
        return 0;
 }
@@ -201,7 +208,7 @@ unsigned int preload_control_get_bin_names(char ***filenames_p)
        struct bin_desc *p;
        char **a = NULL;
 
-       down_read(&target_binaries_lock);
+       read_lock(&target_binaries_lock);
        if (target_binaries_cnt == 0)
                goto out;
 
@@ -219,7 +226,7 @@ unsigned int preload_control_get_bin_names(char ***filenames_p)
        *filenames_p = a;
        ret = i;
 out:
-       up_read(&target_binaries_lock);
+       read_unlock(&target_binaries_lock);
        return ret;
 }