Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.0 240/346] x86/uaccess, ftrace: Fix ftrace_likely_update() vs. SMAP | Date | Wed, 29 May 2019 20:05:13 -0700 |
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[ 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> --- kernel/trace/trace_branch.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c index 4ad967453b6fb..3ea65cdff30d5 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); -- 2.20.1
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