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Diffstat (limited to 'kernel/kmod.c')
-rw-r--r--kernel/kmod.c84
1 files changed, 69 insertions, 15 deletions
diff --git a/kernel/kmod.c b/kernel/kmod.c
index a0a8854..957a7aa 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -60,6 +60,43 @@ static DECLARE_RWSEM(umhelper_sem);
*/
char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe";
+static void free_modprobe_argv(struct subprocess_info *info)
+{
+ kfree(info->argv[3]); /* check call_modprobe() */
+ kfree(info->argv);
+}
+
+static int call_modprobe(char *module_name, int wait)
+{
+ static char *envp[] = {
+ "HOME=/",
+ "TERM=linux",
+ "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
+ NULL
+ };
+
+ char **argv = kmalloc(sizeof(char *[5]), GFP_KERNEL);
+ if (!argv)
+ goto out;
+
+ module_name = kstrdup(module_name, GFP_KERNEL);
+ if (!module_name)
+ goto free_argv;
+
+ argv[0] = modprobe_path;
+ argv[1] = "-q";
+ argv[2] = "--";
+ argv[3] = module_name; /* check free_modprobe_argv() */
+ argv[4] = NULL;
+
+ return call_usermodehelper_fns(modprobe_path, argv, envp,
+ wait | UMH_KILLABLE, NULL, free_modprobe_argv, NULL);
+free_argv:
+ kfree(argv);
+out:
+ return -ENOMEM;
+}
+
/**
* __request_module - try to load a kernel module
* @wait: wait (or not) for the operation to complete
@@ -81,11 +118,6 @@ int __request_module(bool wait, const char *fmt, ...)
char module_name[MODULE_NAME_LEN];
unsigned int max_modprobes;
int ret;
- char *argv[] = { modprobe_path, "-q", "--", module_name, NULL };
- static char *envp[] = { "HOME=/",
- "TERM=linux",
- "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
- NULL };
static atomic_t kmod_concurrent = ATOMIC_INIT(0);
#define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */
static int kmod_loop_msg;
@@ -128,9 +160,7 @@ int __request_module(bool wait, const char *fmt, ...)
trace_module_request(module_name, wait, _RET_IP_);
- ret = call_usermodehelper_fns(modprobe_path, argv, envp,
- wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC,
- NULL, NULL, NULL);
+ ret = call_modprobe(module_name, wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC);
atomic_dec(&kmod_concurrent);
return ret;
@@ -188,7 +218,7 @@ static int ____call_usermodehelper(void *data)
/* Exec failed? */
fail:
sub_info->retval = retval;
- do_exit(0);
+ return 0;
}
void call_usermodehelper_freeinfo(struct subprocess_info *info)
@@ -199,6 +229,19 @@ void call_usermodehelper_freeinfo(struct subprocess_info *info)
}
EXPORT_SYMBOL(call_usermodehelper_freeinfo);
+static void umh_complete(struct subprocess_info *sub_info)
+{
+ struct completion *comp = xchg(&sub_info->complete, NULL);
+ /*
+ * See call_usermodehelper_exec(). If xchg() returns NULL
+ * we own sub_info, the UMH_KILLABLE caller has gone away.
+ */
+ if (comp)
+ complete(comp);
+ else
+ call_usermodehelper_freeinfo(sub_info);
+}
+
/* Keventd can't block, but this (a child) can. */
static int wait_for_helper(void *data)
{
@@ -235,7 +278,7 @@ static int wait_for_helper(void *data)
sub_info->retval = ret;
}
- complete(sub_info->complete);
+ umh_complete(sub_info);
return 0;
}
@@ -244,7 +287,7 @@ static void __call_usermodehelper(struct work_struct *work)
{
struct subprocess_info *sub_info =
container_of(work, struct subprocess_info, work);
- enum umh_wait wait = sub_info->wait;
+ int wait = sub_info->wait & ~UMH_KILLABLE;
pid_t pid;
/* CLONE_VFORK: wait until the usermode helper has execve'd
@@ -269,7 +312,7 @@ static void __call_usermodehelper(struct work_struct *work)
case UMH_WAIT_EXEC:
if (pid < 0)
sub_info->retval = pid;
- complete(sub_info->complete);
+ umh_complete(sub_info);
}
}
@@ -435,8 +478,7 @@ EXPORT_SYMBOL(call_usermodehelper_setfns);
* asynchronously if wait is not set, and runs as a child of keventd.
* (ie. it runs with full root capabilities).
*/
-int call_usermodehelper_exec(struct subprocess_info *sub_info,
- enum umh_wait wait)
+int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
{
DECLARE_COMPLETION_ONSTACK(done);
int retval = 0;
@@ -456,9 +498,21 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info,
queue_work(khelper_wq, &sub_info->work);
if (wait == UMH_NO_WAIT) /* task has freed sub_info */
goto unlock;
+
+ if (wait & UMH_KILLABLE) {
+ retval = wait_for_completion_killable(&done);
+ if (!retval)
+ goto wait_done;
+
+ /* umh_complete() will see NULL and free sub_info */
+ if (xchg(&sub_info->complete, NULL))
+ goto unlock;
+ /* fallthrough, umh_complete() was already called */
+ }
+
wait_for_completion(&done);
+wait_done:
retval = sub_info->retval;
-
out:
call_usermodehelper_freeinfo(sub_info);
unlock:
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