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authorTejun Heo <tj@kernel.org>2010-04-05 11:37:28 +0900
committerTejun Heo <tj@kernel.org>2010-04-05 11:37:28 +0900
commit336f5899d287f06d8329e208fc14ce50f7ec9698 (patch)
tree9b762d450d5eb248a6ff8317badb7e223d93ed58 /arch/arm/kernel
parenta4ab2773205e8b94c18625455f85e3b6bb9d7ad6 (diff)
parentdb217dece3003df0841bacf9556b5c06aa097dae (diff)
downloadlinux-336f5899d287f06d8329e208fc14ce50f7ec9698.tar.gz
Merge branch 'master' into export-slabh
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r--arch/arm/kernel/kprobes.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c
index 1fb932b4fece..2ba7deb3072e 100644
--- a/arch/arm/kernel/kprobes.c
+++ b/arch/arm/kernel/kprobes.c
@@ -394,6 +394,14 @@ void __kprobes jprobe_return(void)
 		/*
 		 * Setup an empty pt_regs. Fill SP and PC fields as
 		 * they're needed by longjmp_break_handler.
+		 *
+		 * We allocate some slack between the original SP and start of
+		 * our fabricated regs. To be precise we want to have worst case
+		 * covered which is STMFD with all 16 regs so we allocate 2 *
+		 * sizeof(struct_pt_regs)).
+		 *
+		 * This is to prevent any simulated instruction from writing
+		 * over the regs when they are accessing the stack.
 		 */
 		"sub    sp, %0, %1		\n\t"
 		"ldr    r0, ="__stringify(JPROBE_MAGIC_ADDR)"\n\t"
@@ -411,7 +419,7 @@ void __kprobes jprobe_return(void)
 		"ldmia	sp, {r0 - pc}		\n\t"
 		:
 		: "r" (kcb->jprobe_saved_regs.ARM_sp),
-		  "I" (sizeof(struct pt_regs)),
+		  "I" (sizeof(struct pt_regs) * 2),
 		  "J" (offsetof(struct pt_regs, ARM_sp)),
 		  "J" (offsetof(struct pt_regs, ARM_pc)),
 		  "J" (offsetof(struct pt_regs, ARM_cpsr))