| Message ID | 20190814104131.20190-7-mark.rutland@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | kthread detection cleanup | expand |
From: Mark Rutland <mark.rutland@arm.com> Date: Wed, 14 Aug 2019 11:41:28 +0100 > 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> Acked-by: David S. Miller <davem@davemloft.net>
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();
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(-) -- 2.11.0