Andrew Morton wrote: > Greg KH wrote: > >>>The deadlock opportunity occurs during the call_usermodehelper() handoff to >> >> > keventd, which is synchronous. >> > >> > 2-3 years back I did have a call_usermodehelper() which was fully async. >> > It was pretty unpleasant because of the need to atomically allocate >> > arbitrary amounts of memory to hold the argv[] and endp[] arrays, to pass >> > them between a couple of threads and to then correctly free it all up >> > again. >> >> Ok, you've convinced me of the mess that would cause. So what should we >> do to help fix this? Serialize call_usermodehelper()? > > > May as well bring back call_usermodehelper_async() I guess. > > > There are two patches here, and they are totally untested... I loaded the patches on my ppc64 box and they worked fine after I fixed a compile bug. The attached patch fixes the compile bug and changes the call_usermodehelper call in kset_hotplug to call_usermodehelper_async. -Brian -- Brian King eServer Storage I/O IBM Linux Technology Center