Messages in this thread | | | Date | Tue, 17 Apr 2001 09:07:40 +0530 | From | Maneesh Soni <> | Subject | Re: module load/unload race protection? |
| |
On Sat, Apr 14, 2001 at 12:26:40PM +0200, Mikael Pettersson wrote: > Does the kernel's module loader (kernel/module.c, not kmod) > protect adequately against concurrent load/load or load/unload > requests? The question applies to both 2.2 and 2.4 kernels. > > I'm trying to track down a problem where a user using a > RedHat 2.2.17-14 SMP kernel managed to trigger a situation where > a driver module had been unloaded while still being in use > (as in "the kernel has pointers into it", not USE_COUNT != 0). > I'm reviewing the driver's internal INC/DEC_USE_COUNT usage, > but so far I've not found any obvious errors. > > /Mikael
There are race conditions while module unloading, present in both 2.2 and 2.4 kernels. Efforts are being made in handling these races by using read-copy-update mechanism (http://lse.sourceforge.net/locking/rclock.html) and by using synchronize_kernel() (from Rusty Russell, Keith Owens).
Regards, Maneesh
-- Maneesh Soni <smaneesh@in.ibm.com> http://lse.sourceforge.net/locking/rclock.html IBM Linux Technology Center, IBM Software Lab, Bangalore, India - 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/
| |