From 05f54c13cd0c33694eec39a265475c5d6cf223cf Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Thu, 16 Apr 2009 21:55:29 +0100 Subject: Revert "kobject: don't block for each kobject_uevent". This reverts commit f520360d93cdc37de5d972dac4bf3bdef6a7f6a7. Tetsuo Handa, running a kernel with CONFIG_DEBUG_PAGEALLOC=y and CONFIG_UEVENT_HELPER_PATH=/sbin/hotplug, has been hitting RCU detected CPU stalls: it's been spinning in the loop where do_execve() counts up the args (but why wasn't fixup_exception working? dunno). The recent change, switching kobject_uevent_env() from UMH_WAIT_EXEC to UMH_NO_WAIT, is broken: the exec uses args on the local stack here, and an env which is kfreed as soon as call_usermodehelper() returns. It very much needs to wait for the exec to be done. An alternative would be to keep the UMH_NO_WAIT, and complicate the code to allocate and free these resources correctly? but no, as GregKH pointed out when making the commit, CONFIG_UEVENT_HELPER_PATH="" is a much better optimization - though some distros are still saying /sbin/hotplug in their .config, yet with no such binary in their initrd or their root. Reported-by: Tetsuo Handa Signed-off-by: Hugh Dickins Acked-by: Greg Kroah-Hartman Acked-by: Arjan van de Ven Acked-by: Will Newton Signed-off-by: Linus Torvalds --- lib/kobject_uevent.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/kobject_uevent.c') diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index 97a777ad4f5..dafeecf5b14 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -258,7 +258,7 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, goto exit; retval = call_usermodehelper(argv[0], argv, - env->envp, UMH_NO_WAIT); + env->envp, UMH_WAIT_EXEC); } exit: -- cgit v1.2.3-70-g09d2 From d094cbe998eb566d47552aa9d3c26c9123a7b858 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Fri, 3 Apr 2009 19:04:15 +0200 Subject: driver core: allow non-root users to listen to uevents Users can read sysfs files, there is no reason they should not be allowed to listen to uevents. This lets xorg and other userspace programs properly get these messages without having to be root. Signed-off-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- lib/kobject_uevent.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/kobject_uevent.c') diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index dafeecf5b14..920a3ca6e25 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -328,7 +328,7 @@ static int __init kobject_uevent_init(void) "kobject_uevent: unable to create netlink socket!\n"); return -ENODEV; } - + netlink_set_nonroot(NETLINK_KOBJECT_UEVENT, NL_NONROOT_RECV); return 0; } -- cgit v1.2.3-70-g09d2