From mboxrd@z Thu Jan 1 00:00:00 1970 From: wangnan0@huawei.com (Wang Nan) Date: Thu, 12 Feb 2015 20:19:31 +0800 Subject: [RFC PATCH v2 04/26] ftrace: don't update record flags if code modification fail. In-Reply-To: <1423743476-11927-1-git-send-email-wangnan0@huawei.com> References: <1423743476-11927-1-git-send-email-wangnan0@huawei.com> Message-ID: <1423743571-12180-1-git-send-email-wangnan0@huawei.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- 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