[BUGFIX][PATCH] prevent boosting kprobes on exception address

[Masami Hiramatsu]

Don't boost at the addresses which are listed on exception tables,
because major page fault will occur on those addresses. In that case,
kprobes can not ensure that when instruction buffer can be freed
since some processes will sleep on the buffer.
(kprobes-ia64 already has same check.)

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
---
 arch/x86/kernel/kprobes.c |    3 +++
 1 file changed, 3 insertions(+)

Index: mmotm/arch/x86/kernel/kprobes.c
===================================================================
--- mmotm.orig/arch/x86/kernel/kprobes.c
+++ mmotm/arch/x86/kernel/kprobes.c
@@ -193,6 +193,9 @@ static int __kprobes can_boost(kprobe_op
 	kprobe_opcode_t opcode;
 	kprobe_opcode_t *orig_opcodes = opcodes;

+	if (search_exception_tables(opcodes))
+		return 0;	/* Page fault may occur on this address. */
+
 retry:
 	if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
 		return 0;
-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@xxxxxxxxxx


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/