[RFC PATCH v4 20/34] ftrace/x86: Ensure rec->flags no change when failure occures.

From: Wang Nan
Date: Mon Mar 02 2015 - 09:32:03 EST


Don't change rec->flags if code modification fails.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
---
arch/x86/kernel/ftrace.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 8b7b0a5..7bdba65 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -497,6 +497,7 @@ static int finish_update(struct dyn_ftrace *rec, int enable)
{
unsigned long ftrace_addr;
int ret;
+ unsigned long old_flags = rec->flags;

ret = ftrace_update_record(rec, enable);

@@ -509,14 +510,18 @@ static int finish_update(struct dyn_ftrace *rec, int enable)
case FTRACE_UPDATE_MODIFY_CALL:
case FTRACE_UPDATE_MAKE_CALL:
/* converting nop to call */
- return finish_update_call(rec, ftrace_addr);
+ ret = finish_update_call(rec, ftrace_addr);
+ break;

case FTRACE_UPDATE_MAKE_NOP:
/* converting a call to a nop */
- return finish_update_nop(rec);
+ ret = finish_update_nop(rec);
+ break;
}

- return 0;
+ if (ret)
+ rec->flags = old_flags;
+ return ret;
}

static void do_sync_core(void *data)
--
1.8.4

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