提交 1a3188d7 编写于 作者: P Peter Zijlstra 提交者: Greg Kroah-Hartman

x86/uaccess, ftrace: Fix ftrace_likely_update() vs. SMAP

[ Upstream commit 4a6c91fbdef846ec7250b82f2eeeb87ac5f18cf9 ]

For CONFIG_TRACE_BRANCH_PROFILING=y the likely/unlikely things get
overloaded and generate callouts to this code, and thus also when
AC=1.

Make it safe.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
上级 da30c277
......@@ -205,6 +205,8 @@ 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++;
......@@ -223,6 +225,8 @@ 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);
......
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