linux-kernel - [PATCH 4.19 05/72] Revert "x86/uaccess, ftrace: Fix ftrace_likely

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Message-Id: <20190702080124.848495406@linuxfoundation.org>
Date:   Tue,  2 Jul 2019 10:01:06 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 05/72] Revert "x86/uaccess, ftrace: Fix ftrace_likely_update() vs. SMAP"

This reverts commit 1a3188d737ceb922166d8fe78a5fc4f89907e31b, which was
upstream commit 4a6c91fbdef846ec7250b82f2eeeb87ac5f18cf9.

On Tue, Jun 25, 2019 at 09:39:45AM +0200, Sebastian Andrzej Siewior wrote:
>Please backport commit e74deb11931ff682b59d5b9d387f7115f689698e to
>stable _or_ revert the backport of commit 4a6c91fbdef84 ("x86/uaccess,
>ftrace: Fix ftrace_likely_update() vs. SMAP"). It uses
>user_access_{save|restore}() which has been introduced in the following
>commit.

Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 kernel/trace/trace_branch.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 3ea65cdff30d..4ad967453b6f 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -205,8 +205,6 @@ void trace_likely_condition(struct ftrace_likely_data *f, int val, int expect)
 void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 			  int expect, int is_constant)
 {
-	unsigned long flags = user_access_save();
-
 	/* A constant is always correct */
 	if (is_constant) {
 		f->constant++;
@@ -225,8 +223,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 		f->data.correct++;
 	else
 		f->data.incorrect++;
-
-	user_access_restore(flags);
 }
 EXPORT_SYMBOL(ftrace_likely_update);
 
-- 
2.20.1