Messages in this thread Patch in this message | | | Date | Mon, 18 Mar 2019 16:38:55 +0100 | From | Peter Zijlstra <> | Subject | [PATCH 15/25] x86/uaccess,ftrace: Fix ftrace_likely_update() vs SMAP |
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For CONFIG_TRACE_BRANCH_PROFILING the likely/unlikely things get overloaded and generate callouts to this code, and thus also when AC=1.
Make it safe.
Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/trace/trace_branch.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/kernel/trace/trace_branch.c +++ b/kernel/trace/trace_branch.c @@ -205,6 +205,8 @@ void trace_likely_condition(struct ftrac 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_ f->data.correct++; else f->data.incorrect++; + + user_access_restore(flags); } EXPORT_SYMBOL(ftrace_likely_update);
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