linux-kernel - Re: [PATCH v1] tty: Register device *after* creating the cdev for a tty

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Message-ID: <bcbc2f6f-9935-415c-ac79-f839afe6204d@enpas.org>
Date: Wed, 28 May 2025 22:31:15 +0900
From: Max <max@...as.org>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Jiri Slaby <jirislaby@...nel.org>, linux-serial@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] tty: Register device *after* creating the cdev for a
 tty

On 5/28/25 17:23, Greg Kroah-Hartman wrote:
> As 0-day points out, I think this adds a new locking issue :(
> 
> But it's really hard to detect this, as you are doing both a revert and
> a change in the same commit.  Can you make this as 2 patches, one that
> does the revert which would be "easy" to review, and the second one that
> does the new fix?  That way we can detect what is going on easier.

Done!

Thanks for reviewing this, I've scratched my head about this locking for 
a while, and just when I thought I had used a suitable lock... Well, 
that's where maintainers (and now automation) come in :)


>> Fixes: 6a7e6f78c235 ("tty: close race between device register and open")
>> Signed-off-by: Max Staudt <max@...as.org>
> 
> You also forgot to add cc: stable on this :(

Done. I wasn't sure whether this needs to go to -stable, but since 
you're the maintainer for both tty and stable, I figured you'd make a 
choice anyway.


Thanks,
Max