linux-kernel - Re: [PATCH] devcoredump: Send uevent once devcd is ready

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Message-ID: <c4abc49c31643baa34bf889d689e8c587c28da54.camel@sipsolutions.net>
Date:   Mon, 06 Nov 2023 20:37:33 +0100
From:   Johannes Berg <johannes@...solutions.net>
To:     Greg KH <gregkh@...uxfoundation.org>,
        Mukesh Ojha <quic_mojha@...cinc.com>
Cc:     rafael@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] devcoredump: Send uevent once devcd is ready

On Mon, 2023-11-06 at 20:36 +0100, Greg KH wrote:
> On Mon, Nov 06, 2023 at 07:55:35PM +0530, Mukesh Ojha wrote:
> > dev_coredumpm() creates a devcoredump device and adds it
> > to the core kernel framework which eventually end up
> > sending uevent to the user space and later creates a
> > symbolic link to the failed device. An application
> > running in userspace may be interested in this symbolic
> > link to get the name of the failed device.
> > 
> > In a issue scenario, once uevent sent to the user space
> > it start reading '/sys/class/devcoredump/devcdX/failing_device'
> > to get the actual name of the device which might not been
> > created and it is in its path of creation.
> > 
> > To fix this, suppress sending uevent till the failing device
> > symbolic link gets created and send uevent once symbolic
> > link is created successfully.
> > 
> > Signed-off-by: Mukesh Ojha <quic_mojha@...cinc.com>
> 
> What commit id does this fix? 
> 

I guess the original introduction.

>  What in-kernel driver does this affect
> that is using devcoredump?
> 

All of them really, it's really about how fast userspace is to access it
after the event.

Looks fine to me, FWIW, but a Fixes tag wouldn't hurt.

johannes