diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2019-03-07 11:09:13 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-31 06:47:30 -0700 |
| commit | 8190d6fbb1e9b7fa4eb41fe7aa337c46ca514e79 (patch) | |
| tree | 2d7c580cee444fe30620c88b16333ef75cd41d03 /kernel/trace | |
| parent | 5399fba1d5d23e7fd484307d0c6d340ad83eefa3 (diff) | |
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: Peter 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: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace_branch.c | 4 |
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); |