Messages in this thread | | | From | Kay Sievers <> | Date | Thu, 4 Aug 2011 03:15:51 +0200 | Subject | Re: [PATCH] shm: fix a race between shm_exit() and shm_init() |
| |
On Thu, Aug 4, 2011 at 03:01, Linus Torvalds <torvalds@linux-foundation.org> wrote: > On Wed, Aug 3, 2011 at 2:50 PM, Andrew Morton <akpm@linux-foundation.org> wrote: >> >> Well, it's still a workaround. We'll still have driver_init() trying >> to run userspace helpers at an inappropriate time, and failing to do >> so. Either something will break or it should not be attempting >> attempting to do this at all. > > Well, it has never worked before either, so I wouldn't call it a > "workaround", more of a "insane subsystems do user-mode helpers for > crazy small things, and at crazy times. Stop them from wasting our > time and effort at those crazy times when we know they would fail > anyway". > >> Perhaps Kay and Greg can suggest how we can fix all this up? > > I think just not calling user-mode when user-mode isn't ready is a real fix.
Yes, we should default to off, and probably only enable it just right before we start /sbin/init from the mounted root or in initramfs. There should be no useful use of /sbin/hotplug before we mounted root, or unpacked initramfs.
> The fact that the device models send an absolutely *insane* amount of > events for everything, and don't track "this is the bootup device > scan" on their own is kind of sad, but it's how they roll. This fixes > it at a core level, so that the device layer doesn't have to track the > "am I booting, or is this a dynamic event?" at all.
It is insane, and the entire uevent hookup with /sbin/hotplug should just be removed. We send from 1000 to many 1000s of events at bootup, and forking a binary here makes not much sense these days.
All distros default to CONFIG_UEVENT_HELPER_PATH="" because nothing else really works anymore, some boxes don't even boot up. /sbin/hotplug worked fine when we all had one USB mouse connected and needed to load like 5 drivers for the system, but not today.
It's a broken concept today, at least in the way we plug it into the driver core makes no sense today, it is just a heritage from the old days.
Kay -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |