From: Lennert Buytenhek Date: Fri, 5 Dec 2008 02:25:47 +0000 (+0100) Subject: [ARM] 5340/1: fix stack placement after noexecstack changes X-Git-Tag: v2.6.28-rc8~34^2~1 X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?p=linux-2.6-omap-h63xx.git;a=commitdiff_plain;h=794baba637999b81aa40e60fae1fa91978e08808 [ARM] 5340/1: fix stack placement after noexecstack changes Commit 8ec53663d2698076468b3e1edc4e1b418bd54de3 ("[ARM] Improve non-executable support") added support for detecting non-executable stack binaries. One of the things it does is to make READ_IMPLIES_EXEC be set in ->personality if we are running on a CPU that doesn't support the XN ("Execute Never") page table bit or if we are running a binary that needs an executable stack. This exposed a latent bug in ARM's asm/processor.h due to which we'll end up placing the stack at a very low address, where it will bump into the heap on any application that uses significant amount of stack or heap or both, causing many interesting crashes. Fix this by testing the ADDR_LIMIT_32BIT bit in ->personality instead of testing for equality against PER_LINUX_32BIT. Reviewed-by: Nicolas Pitre Signed-off-by: Lennert Buytenhek Signed-off-by: Russell King --- diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h index 517a4d6ffc7..6ff33790f47 100644 --- a/arch/arm/include/asm/processor.h +++ b/arch/arm/include/asm/processor.h @@ -23,7 +23,7 @@ #include #ifdef __KERNEL__ -#define STACK_TOP ((current->personality == PER_LINUX_32BIT) ? \ +#define STACK_TOP ((current->personality & ADDR_LIMIT_32BIT) ? \ TASK_SIZE : TASK_SIZE_26) #define STACK_TOP_MAX TASK_SIZE #endif