X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fkmod.c;h=4d32eb077179a2babd3f49b9f31631d4c6e27bb7;hb=14531189f0a1071b928586e9e1a89eceac91d95f;hp=3a7379aa31ca6b0a92bec377a23e5c9debed72db;hpb=e7b3ca08549caccf5d6e1cf066780bf4f0ae77a7;p=linux-2.6

diff --git a/kernel/kmod.c b/kernel/kmod.c
index 3a7379aa31..4d32eb0771 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -23,7 +23,6 @@
 #include <linux/syscalls.h>
 #include <linux/unistd.h>
 #include <linux/kmod.h>
-#include <linux/smp_lock.h>
 #include <linux/slab.h>
 #include <linux/mnt_namespace.h>
 #include <linux/completion.h>
@@ -136,7 +135,6 @@ static int ____call_usermodehelper(void *data)
 
 	/* Unblock all signals and set the session keyring. */
 	new_session = key_get(sub_info->ring);
-	flush_signals(current);
 	spin_lock_irq(&current->sighand->siglock);
 	old_session = __install_session_keyring(current, new_session);
 	flush_signal_handlers(current, 1);
@@ -166,6 +164,12 @@ static int ____call_usermodehelper(void *data)
 	/* We can run anywhere, unlike our parent keventd(). */
 	set_cpus_allowed(current, CPU_MASK_ALL);
 
+	/*
+	 * Our parent is keventd, which runs with elevated scheduling priority.
+	 * Avoid propagating that into the userspace child.
+	 */
+	set_user_nice(current, 0);
+
 	retval = -EPERM;
 	if (current->fs->root)
 		retval = kernel_execve(sub_info->path,
@@ -181,14 +185,9 @@ static int wait_for_helper(void *data)
 {
 	struct subprocess_info *sub_info = data;
 	pid_t pid;
-	struct k_sigaction sa;
 
 	/* Install a handler: if SIGCLD isn't handled sys_wait4 won't
 	 * populate the status, but will return -ECHILD. */
-	sa.sa.sa_handler = SIG_IGN;
-	sa.sa.sa_flags = 0;
-	siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD));
-	do_sigaction(SIGCHLD, &sa, NULL);
 	allow_signal(SIGCHLD);
 
 	pid = kernel_thread(____call_usermodehelper, sub_info, SIGCHLD);
@@ -217,7 +216,10 @@ static int wait_for_helper(void *data)
 			sub_info->retval = ret;
 	}
 
-	complete(sub_info->complete);
+	if (sub_info->wait < 0)
+		kfree(sub_info);
+	else
+		complete(sub_info->complete);
 	return 0;
 }
 
@@ -239,6 +241,9 @@ static void __call_usermodehelper(struct work_struct *work)
 		pid = kernel_thread(____call_usermodehelper, sub_info,
 				    CLONE_VFORK | SIGCHLD);
 
+	if (wait < 0)
+		return;
+
 	if (pid < 0) {
 		sub_info->retval = pid;
 		complete(sub_info->complete);
@@ -253,6 +258,9 @@ static void __call_usermodehelper(struct work_struct *work)
  * @envp: null-terminated environment list
  * @session_keyring: session keyring for process (NULL for an empty keyring)
  * @wait: wait for the application to finish and return status.
+ *        when -1 don't wait at all, but you get no useful error back when
+ *        the program couldn't be exec'ed. This makes it safe to call
+ *        from interrupt context.
  *
  * Runs a user-space application.  The application is started
  * asynchronously if wait is not set, and runs as a child of keventd.
@@ -265,17 +273,8 @@ int call_usermodehelper_keys(char *path, char **argv, char **envp,
 			     struct key *session_keyring, int wait)
 {
 	DECLARE_COMPLETION_ONSTACK(done);
-	struct subprocess_info sub_info = {
-		.work		= __WORK_INITIALIZER(sub_info.work,
-						     __call_usermodehelper),
-		.complete	= &done,
-		.path		= path,
-		.argv		= argv,
-		.envp		= envp,
-		.ring		= session_keyring,
-		.wait		= wait,
-		.retval		= 0,
-	};
+	struct subprocess_info *sub_info;
+	int retval;
 
 	if (!khelper_wq)
 		return -EBUSY;
@@ -283,9 +282,25 @@ int call_usermodehelper_keys(char *path, char **argv, char **envp,
 	if (path[0] == '\0')
 		return 0;
 
-	queue_work(khelper_wq, &sub_info.work);
+	sub_info = kzalloc(sizeof(struct subprocess_info),  GFP_ATOMIC);
+	if (!sub_info)
+		return -ENOMEM;
+
+	INIT_WORK(&sub_info->work, __call_usermodehelper);
+	sub_info->complete = &done;
+	sub_info->path = path;
+	sub_info->argv = argv;
+	sub_info->envp = envp;
+	sub_info->ring = session_keyring;
+	sub_info->wait = wait;
+
+	queue_work(khelper_wq, &sub_info->work);
+	if (wait < 0) /* task has freed sub_info */
+		return 0;
 	wait_for_completion(&done);
-	return sub_info.retval;
+	retval = sub_info->retval;
+	kfree(sub_info);
+	return retval;
 }
 EXPORT_SYMBOL(call_usermodehelper_keys);