From: Michael Neuling Date: Mon, 16 Dec 2013 04:12:43 +0000 (+1100) Subject: powerpc: Fix bad stack check in exception entry X-Git-Tag: v3.13-rc7~12^2~7 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=90ff5d688e61f49f23545ffab6228bd7e87e6dc7;p=pandora-kernel.git powerpc: Fix bad stack check in exception entry In EXCEPTION_PROLOG_COMMON() we check to see if the stack pointer (r1) is valid when coming from the kernel. If it's not valid, we die but with a nice oops message. Currently we allocate a stack frame (subtract INT_FRAME_SIZE) before we check to see if the stack pointer is negative. Unfortunately, this won't detect a bad stack where r1 is less than INT_FRAME_SIZE. This patch fixes the check to compare the modified r1 with -INT_FRAME_SIZE. With this, bad kernel stack pointers (including NULL pointers) are correctly detected again. Kudos to Paulus for finding this. Signed-off-by: Michael Neuling cc: stable@vger.kernel.org Signed-off-by: Benjamin Herrenschmidt --- Reading git-diff-tree failed