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-rw-r--r--arch/arm/kernel/unwind.c19
1 files changed, 9 insertions, 10 deletions
diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index 1dedc2c7ff4..dd56e11f339 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -212,7 +212,8 @@ static int unwind_exec_insn(struct unwind_ctrl_block *ctrl)
ctrl->vrs[14] = *vsp++;
ctrl->vrs[SP] = (unsigned long)vsp;
} else if (insn == 0xb0) {
- ctrl->vrs[PC] = ctrl->vrs[LR];
+ if (ctrl->vrs[PC] == 0)
+ ctrl->vrs[PC] = ctrl->vrs[LR];
/* no further processing */
ctrl->entries = 0;
} else if (insn == 0xb1) {
@@ -309,18 +310,20 @@ int unwind_frame(struct stackframe *frame)
}
while (ctrl.entries > 0) {
- int urc;
-
- if (ctrl.vrs[SP] < low || ctrl.vrs[SP] >= high)
- return -URC_FAILURE;
- urc = unwind_exec_insn(&ctrl);
+ int urc = unwind_exec_insn(&ctrl);
if (urc < 0)
return urc;
+ if (ctrl.vrs[SP] < low || ctrl.vrs[SP] >= high)
+ return -URC_FAILURE;
}
if (ctrl.vrs[PC] == 0)
ctrl.vrs[PC] = ctrl.vrs[LR];
+ /* check for infinite loop */
+ if (frame->pc == ctrl.vrs[PC])
+ return -URC_FAILURE;
+
frame->fp = ctrl.vrs[FP];
frame->sp = ctrl.vrs[SP];
frame->lr = ctrl.vrs[LR];
@@ -332,7 +335,6 @@ int unwind_frame(struct stackframe *frame)
void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk)
{
struct stackframe frame;
- unsigned long high, low;
register unsigned long current_sp asm ("sp");
pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
@@ -362,9 +364,6 @@ void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk)
frame.pc = thread_saved_pc(tsk);
}
- low = frame.sp & ~(THREAD_SIZE - 1);
- high = low + THREAD_SIZE;
-
while (1) {
int urc;
unsigned long where = frame.pc;