On 09/01/15 16:46, Russell King - ARM Linux wrote: > On Mon, Jan 05, 2015 at 03:12:38PM +0000, Daniel Thompson wrote: >> Currently restore_user_regs deallocates the SVC stack early in >> its execution and relies on no exception being taken between >> the deallocation and the registers being restored. The introduction >> of a default FIQ handler that also uses the SVC stack breaks this >> assumption and can result in corrupted register state. >> >> This patch works around the problem by removing the early >> stack deallocation and using r2 as a temporary instead. I have >> not found a way to do this without introducing an extra mov >> instruction to the macro. >> >> Signed-off-by: Daniel Thompson <[email protected]> >> --- > > Please put it in the patch system, thanks.
Will do. > I think we should queue > this one for stable too, as I think we need this for v3.18 > (as a result of c0e7f7ee717e2b4c5791e7422424c96b5008c39e, > ARM: 8150/3: fiq: Replace default FIQ handler)? It's a close call. Before 8150/3 the system would probably crash if the default FIQ handler ran. After 8150/3 the system is also likely to crash since there's no code hooked into the handler in v3.18 that can clear the source of FIQ leaving us stuck re-entering the FIQ handler. Nevertheless, this is a nasty gremlin to leave for backporters (it wasn't easy to find) so I'd be very happy to Cc: stable and see what they think. Daniel. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
