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Subject[PATCH 6/9] sparc/perf: correctly check for kthreads
Date
The sparc perf_callchain_user() functions looks at current->mm,
apparently to determine whether the thread is a kthread without any
valid user context.

In general, a non-NULL current->mm doesn't imply that current is a
kthread, as kthreads can install an mm via use_mm(), and so it's
preferable to use is_kthread() to determine whether a thread is a
kthread.

For consistency, let's use is_kthread() here.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
---
arch/sparc/kernel/perf_event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index a58ae9c42803..ef7b1a03bea9 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -1858,7 +1858,7 @@ perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs

perf_callchain_store(entry, regs->tpc);

- if (!current->mm)
+ if (is_kthread(current))
return;

flushw_user();
--
2.11.0
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