From: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
GDB uses a variant of the trap instruction that is different from the
one used by uprobes. Currently, running gdb on a program being traced
by uprobes causes an endless loop since uprobes doesn't understand
that the trap is inserted by some other entity and hence a SIGTRAP needs
to be delivered.
Teach uprobes to ignore breakpoints that doesn't belong to it.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
arch/powerpc/kernel/uprobes.c | 10 ++++++++++
1 file changed, 10 insertions(+)
Index: linux-3.9-rc3/arch/powerpc/kernel/uprobes.c
===================================================================
--- linux-3.9-rc3.orig/arch/powerpc/kernel/uprobes.c
+++ linux-3.9-rc3/arch/powerpc/kernel/uprobes.c
@@ -80,6 +80,16 @@ unsigned long uprobe_get_swbp_addr(struc
return instruction_pointer(regs);
}
+/**
+ * is_swbp_insn - check if the instruction is a breakpoint instruction.
+ * @insn: instruction to be checked.
+ * Returns true if @insn is a breakpoint instruction.
+ */
+bool is_swbp_insn(uprobe_opcode_t *insn)
+{
+ return (is_trap(*insn));
+}
+
/*
* If xol insn itself traps and generates a signal (SIGILL/SIGSEGV/etc),
* then detect the case where a singlestepped instruction jumps back to its
--
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