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authorPeter Zijlstra <[email protected]>2019-03-07 11:09:13 +0100
committerIngo Molnar <[email protected]>2019-04-03 11:02:24 +0200
commit4a6c91fbdef846ec7250b82f2eeeb87ac5f18cf9 (patch)
tree4bc04f2fe05326071feb0d560de2489a899f2d04
parentd08965a27e84ca090b504844d50c24fc98587b11 (diff)
x86/uaccess, ftrace: Fix ftrace_likely_update() vs. SMAP
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: Peter Zijlstra (Intel) <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Thomas Gleixner <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
-rw-r--r--kernel/trace/trace_branch.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 4ad967453b6f..3ea65cdff30d 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -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);