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From: Breno Leitao <leitao@debian.org>
To: Ard Biesheuvel <ardb+git@google.com>
Cc: linux-efi@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>
Subject: Re: [PATCH] efi/runtime-wrappers: Don't park the worker after a recovered firmware fault
Date: Fri, 9 Oct 2026 08:56:02 -0700	[thread overview]
Message-ID: <askOeRkTQRw7SslG@gmail.com> (raw)
In-Reply-To: <20261009144814.338052-2-ardb+git@google.com>

On Fri, Oct 09, 2026 at 04:48:15PM +0200, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.org>
> 
> Commit 4b2c033b5bc9 ("efi/runtime-wrappers: retire the worker if a wedged
> call ever returns") parks the efi_rts_wq worker instead of completing the
> call if EFI runtime services have been disabled by the time the firmware
> returns. The assumption is that this only happens if __efi_queue_work()
> has given up waiting for the call.
> 
> However, arm64 also disables EFI runtime services when it recovers from a
> synchronous exception taken by the firmware: efi_runtime_fixup_exception()
> clears EFI_RUNTIME_SERVICES and unwinds the call so that it returns
> EFI_ABORTED to efi_call_rts(), while the caller is still waiting for the
> completion. The worker now parks without signalling it, so the caller is
> stuck for the full EFI_RTS_TIMEOUT of 120 seconds, after which it reports
> that the firmware is wedged, which is misleading.
> 
> x86 is not affected, as it signals the completion from its page fault
> handler before parking the worker.
> 
> So record explicitly that the caller has given up on the call, and only
> park the worker in that case.
> 
> Fixes: 4b2c033b5bc9 ("efi/runtime-wrappers: retire the worker if a wedged call ever returns")
> Cc: Breno Leitao <leitao@debian.org>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Reviewed-by: Breno Leitao <leitao@debian.org>

      reply	other threads:[~2026-10-09 15:56 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-09 14:48 [PATCH] efi/runtime-wrappers: Don't park the worker after a recovered firmware fault Ard Biesheuvel
2026-10-09 15:56 ` Breno Leitao [this message]

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