3.8.13.14 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Kevin Hao <haokexin@xxxxxxxxx>
commit ab4ead02ec235d706d0611d8741964628291237e upstream.
In commit 8a4d0a687a59 "ftrace: Use breakpoint method to update ftrace
caller", we choose to use breakpoint method to update the ftrace
caller. But we also need to skip over the breakpoint in function
ftrace_int3_handler() for them. Otherwise weird things would happen.
Signed-off-by: Kevin Hao <haokexin@xxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
arch/x86/kernel/ftrace.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 1d41402..8d5d9e5 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -248,6 +248,15 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
return ret;
}
+static int is_ftrace_caller(unsigned long ip)
+{
+ if (ip == (unsigned long)(&ftrace_call) ||
+ ip == (unsigned long)(&ftrace_regs_call))
+ return 1;
+
+ return 0;
+}
+
/*
* A breakpoint was added to the code address we are about to
* modify, and this is the handle that will just skip over it.
@@ -257,10 +266,13 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
*/
int ftrace_int3_handler(struct pt_regs *regs)
{
+ unsigned long ip;
+
if (WARN_ON_ONCE(!regs))
return 0;
- if (!ftrace_location(regs->ip - 1))
+ ip = regs->ip - 1;
+ if (!ftrace_location(ip) && !is_ftrace_caller(ip))
return 0;
regs->ip += MCOUNT_INSN_SIZE - 1;
--
1.8.3.2
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