From: "Yang Xu (徐扬)" <Yang.Xu@mediatek.com>
To: "richard.purdie@linuxfoundation.org"
<richard.purdie@linuxfoundation.org>,
"bitbake-devel@lists.openembedded.org"
<bitbake-devel@lists.openembedded.org>
Subject: Re: [bitbake-devel] [PATCH] bitbake-worker: Fix silent hang issue caused by unexpected stdout content
Date: Thu, 22 Feb 2024 06:08:21 +0000 [thread overview]
Message-ID: <aca5f3feb93c42bb1178a4622d1423aa4c2d2b06.camel@mediatek.com> (raw)
In-Reply-To: <dc3e8b3949f3208910cd41da56cc8f1c84bcfb81.camel@linuxfoundation.org>
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Sorry, I noticed this patch has not been merged. Is there any further work that I need to complete?
Or is bitbake planning to swtich to the solution that does not use stdin/stdout directly.
Thank you
On Sun, 2024-02-04 at 23:01 +0000, Richard Purdie wrote:
> This patch addresses an issue in bitbake-worker where stdout,
> reserved for status reporting, is improperly accessed by child processes.
>
> The problem occurs during the execution of parseRecipe,
> which calls anonymous functions. If these functions use print-like operations,
> they can inadvertently output data to stdout. This unexpected data can cause
> the runqueue to hang silently, if the stdout buffer is flushed
> before exec_task is executed.
>
> To prevent this, the patch redirects stdout to /dev/null and ensures it is
> flushed prior to the execution of exec_task.
>
> Signed-off-by: Yang Xu <yang.xu@mediatek.com>
> ---
> bin/bitbake-worker | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/bin/bitbake-worker b/bin/bitbake-worker
> index eba9c562..0ba18572 100755
> --- a/bin/bitbake-worker
> +++ b/bin/bitbake-worker
> @@ -237,9 +237,11 @@ def fork_off_task(cfg, data, databuilder, workerdata, extraconfigdata, runtask):
> # Let SIGHUP exit as SIGTERM
> signal.signal(signal.SIGHUP, sigterm_handler)
>
> - # No stdin
> - newsi = os.open(os.devnull, os.O_RDWR)
> - os.dup2(newsi, sys.stdin.fileno())
> + # No stdin & stdout
> + # stdout is used as a status report channel and must not be used by child processes.
> + dumbio = os.open(os.devnull, os.O_RDWR)
> + os.dup2(dumbio, sys.stdin.fileno())
> + os.dup2(dumbio, sys.stdout.fileno())
>
> if umask:
> os.umask(umask)
> @@ -305,6 +307,10 @@ def fork_off_task(cfg, data, databuilder, workerdata, extraconfigdata, runtask):
> if not quieterrors:
> logger.critical(traceback.format_exc())
> os._exit(1)
> +
> + sys.stdout.flush()
> + sys.stderr.flush()
> +
> try:
> if dry_run:
> return 0
This looks like a good catch.
I'm wondering if we should change the code to use a different file
descriptor for the communication and leave stdout/stderr alone
instead...
Cheers,
Richard
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prev parent reply other threads:[~2024-02-22 6:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-02 9:36 [PATCH] bitbake-worker: Fix silent hang issue caused by unexpected stdout content yang.xu
2024-02-04 23:01 ` [bitbake-devel] " Richard Purdie
2024-02-22 6:08 ` Yang Xu (徐扬) [this message]
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