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Commit ac331d15 authored by KOSAKI Motohiro's avatar KOSAKI Motohiro Committed by Linus Torvalds
Browse files

call_usermodehelper(): increase reliability 



Presently call_usermodehelper_setup() uses GFP_ATOMIC.  but it can return
NULL _very_ easily.

GFP_ATOMIC is needed only when we can't sleep.  and, GFP_KERNEL is robust
and better.

thus, I add gfp_mask argument to call_usermodehelper_setup().

So, its callers pass the gfp_t as below:

call_usermodehelper() and call_usermodehelper_keys():
	depend on 'wait' argument.
call_usermodehelper_pipe():
	always GFP_KERNEL because always run under process context.
orderly_poweroff():
	pass to GFP_ATOMIC because may run under interrupt context.

Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: "Paul Menage" <menage@google.com>
Reviewed-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Acked-by: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f557d099

include/linux/kmod.h

+7 −4
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
 *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 */



#include <linux/gfp.h>

#include <linux/stddef.h>

#include <linux/errno.h>

#include <linux/compiler.h>
@@ -41,8 +42,8 @@ struct file; 
struct subprocess_info;



/* Allocate a subprocess_info structure */

struct subprocess_info *call_usermodehelper_setup(char *path,

						  char **argv, char **envp);

struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,

						  char **envp, gfp_t gfp_mask);



/* Set various pieces of state into the subprocess_info structure */

void call_usermodehelper_setkeys(struct subprocess_info *info,
@@ -69,8 +70,9 @@ static inline int 
call_usermodehelper(char *path, char **argv, char **envp, enum umh_wait wait)

{

	struct subprocess_info *info;

	gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;



	info = call_usermodehelper_setup(path, argv, envp);

	info = call_usermodehelper_setup(path, argv, envp, gfp_mask);

	if (info == NULL)

		return -ENOMEM;

	return call_usermodehelper_exec(info, wait);
@@ -81,8 +83,9 @@ call_usermodehelper_keys(char *path, char **argv, char **envp, 
			 struct key *session_keyring, enum umh_wait wait)

{

	struct subprocess_info *info;

	gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;



	info = call_usermodehelper_setup(path, argv, envp);

	info = call_usermodehelper_setup(path, argv, envp, gfp_mask);

	if (info == NULL)

		return -ENOMEM;

kernel/kmod.c

+5 −4
Original line number Diff line number Diff line
@@ -352,16 +352,17 @@ static inline void register_pm_notifier_callback(void) {} 
 * @path: path to usermode executable

 * @argv: arg vector for process

 * @envp: environment for process

 * @gfp_mask: gfp mask for memory allocation

 *

 * Returns either %NULL on allocation failure, or a subprocess_info

 * structure.  This should be passed to call_usermodehelper_exec to

 * exec the process and free the structure.

 */

struct subprocess_info *call_usermodehelper_setup(char *path,

						  char **argv, char **envp)

struct subprocess_info *call_usermodehelper_setup(char *path, char **argv,

						  char **envp, gfp_t gfp_mask)

{

	struct subprocess_info *sub_info;

	sub_info = kzalloc(sizeof(struct subprocess_info),  GFP_ATOMIC);

	sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask);

	if (!sub_info)

		goto out;
@@ -494,7 +495,7 @@ int call_usermodehelper_pipe(char *path, char **argv, char **envp, 
	struct subprocess_info *sub_info;

	int ret;



	sub_info = call_usermodehelper_setup(path, argv, envp);

	sub_info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL);

	if (sub_info == NULL)

		return -ENOMEM;

kernel/sys.c

+1 −1
Original line number Diff line number Diff line
@@ -1795,7 +1795,7 @@ int orderly_poweroff(bool force) 
		goto out;

	}



	info = call_usermodehelper_setup(argv[0], argv, envp);

	info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);

	if (info == NULL) {

		argv_free(argv);

		goto out;