X86 and common ftrace_replace_code() behave differently.
In x86, rec->flags get updated only when (almost) all works are done. In
common code, rec->flags is updated before code modification, and never
get restored when code modification fails.
This patch ensures rec->flags kept its original value if
ftrace_replace_code() fail. A later patch will correct that function
for x86.
Signed-off-by: Wang Nan <wangn...@huawei.com>
---
kernel/trace/ftrace.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 45e5cb1..6c6cbb1 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2254,23 +2254,30 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int
enable)
/* This needs to be done before we call ftrace_update_record */
ftrace_old_addr = ftrace_get_addr_curr(rec);
- ret = ftrace_update_record(rec, enable);
+ ret = ftrace_test_record(rec, enable);
switch (ret) {
case FTRACE_UPDATE_IGNORE:
return 0;
case FTRACE_UPDATE_MAKE_CALL:
- return ftrace_make_call(rec, ftrace_addr);
+ ret = ftrace_make_call(rec, ftrace_addr);
+ break;
case FTRACE_UPDATE_MAKE_NOP:
- return ftrace_make_nop(NULL, rec, ftrace_old_addr);
+ ret = ftrace_make_nop(NULL, rec, ftrace_old_addr);
+ break;
case FTRACE_UPDATE_MODIFY_CALL:
- return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
+ ret = ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
+ break;
}
- return -1; /* unknow ftrace bug */
+ if (ret)
+ return -1; /* unknow ftrace bug */
+
+ ftrace_update_record(rec, enable);
+ return 0;
}
void __weak ftrace_replace_code(int enable)
--
1.8.4
--
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