From 0d69a052d4d7c4085706b9ac0d1bd28ff90c9fca Mon Sep 17 00:00:00 2001 From: "Gui,Jian" Date: Wed, 1 Nov 2006 10:50:15 +0800 Subject: [PATCH] [POWERPC] Disallow kprobes on emulate_step and branch_taken On powerpc, probing on emulate_step function will crash 2.6.18.1 when it is triggered. When kprobe is triggered, emulate_step() is on its kernel path and will cause recursive kprobe fault. And branch_taken() is called in emulate_step(). This disallows kprobes on both of them. Signed-off-by: Paul Mackerras --- arch/powerpc/lib/sstep.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index 9590ba780b98..7e8ded051b5b 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -9,6 +9,7 @@ * 2 of the License, or (at your option) any later version. */ #include +#include #include #include #include @@ -25,7 +26,7 @@ extern char system_call_common[]; /* * Determine whether a conditional branch instruction would branch. */ -static int branch_taken(unsigned int instr, struct pt_regs *regs) +static int __kprobes branch_taken(unsigned int instr, struct pt_regs *regs) { unsigned int bo = (instr >> 21) & 0x1f; unsigned int bi; @@ -51,7 +52,7 @@ static int branch_taken(unsigned int instr, struct pt_regs *regs) * or -1 if the instruction is one that should not be stepped, * such as an rfid, or a mtmsrd that would clear MSR_RI. */ -int emulate_step(struct pt_regs *regs, unsigned int instr) +int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr) { unsigned int opcode, rd; unsigned long int imm;