On Thu, 7 Jan 2021 14:53:10 +0000, Mark Rutland wrote:

All EL0 returns go via ret_to_user(), which masks IRQs and notifies
lockdep and tracing before calling into do_notify_resume(). Therefore,
there's no need for do_notify_resume() to call trace_hardirqs_off(), and
the comment is stale. The call is simply redundant.

In ret_to_user() we call exit_to_user_mode(), which notifies lockdep and
tracing the IRQs will be enabled in userspace, so there's no need for
el0_svc_common() to call trace_hardirqs_on() before returning. Further,
at the start of ret_to_user() we call trace_hardirqs_off(), so not only
is this redundant, but it is immediately undone.

[...]

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm64: entry: remove redundant IRQ flag tracing
      https://git.kernel.org/arm64/c/df06824767cc

-- 
Catalin


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