On Fri, 23 Dec 2005, Greg KH wrote: > On Fri, Dec 23, 2005 at 04:22:44PM -0500, Alan Stern wrote: > > On Fri, 23 Dec 2005, Pavel Machek wrote: > > > > > Well, if you can find some elegant solution in the core, I think thats > > > the best way. > > > > > > You could set system_state to "suspending" or something like that, and > > > just if() out notifications in that case. > > > > How about simply adding a call to try_to_freeze() somewhere inside > > kernel/kmod.c:____call_usermodehelper()? That ought to do pretty much > > what I want, in theory. The hotplug processes would get frozen before > > /sbin/hotplug is exec'ed. > > On modern distros, /sbin/hotplug is set to NULL, so this isn't an issue. > We use netlink to send the data out, so this might not even be a problem > anymore... Indeed it might not. On my older FC3 system I end up with unwanted processes, but under FC4 that doesn't happen. (Note however that even on the FC4 system, /sbin/hotplug is not empty and /proc/sys/kernel/hotplug does point to /sbin/hotplug.) The ideal situation would be to have PF_FREEZE automatically set for every new process created while userspace was frozen. Kernel threads could remove the flag and set PF_NOFREEZE if they wanted, while user processes would automatically get frozen before returning to userspace. This approach would eliminate all the loopholes at once. Alan Stern
