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From: Greg Kroah-Hartman <>
To: Ben Hutchings <>
Cc: Jiri Slaby <>,
	Gen Zhang <>,
	Kees Cook <>,
	LKML <>
Subject: Re: [PATCH] Revert "consolemap: Fix a memory leaking bug in drivers/tty/vt/consolemap.c"
Date: Tue, 4 Jun 2019 21:02:34 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Tue, Jun 04, 2019 at 07:00:39PM +0100, Ben Hutchings wrote:
> This reverts commit 84ecc2f6eb1cb12e6d44818f94fa49b50f06e6ac.
> con_insert_unipair() is working with a sparse 3-dimensional array:
> - p->uni_pgdir[] is the top layer
> - p1 points to a middle layer
> - p2 points to a bottom layer
> If it needs to allocate a new middle layer, and then fails to allocate
> a new bottom layer, it would previously free only p2, and now it frees
> both p1 and p2.  But since the new middle layer was already registered
> in the top layer, it was not leaked.
> However, if it looks up an *existing* middle layer and then fails to
> allocate a bottom layer, it now frees both p1 and p2 but does *not*
> free any other bottom layers under p1.  So it *introduces* a memory
> leak.
> The error path also cleared the wrong index in p->uni_pgdir[],
> introducing a use-after-free.
> Signed-off-by: Ben Hutchings <>

Now applied, thanks.

Gen, please be careful with these types of "fixes"...


greg k-h

  reply	other threads:[~2019-06-04 19:02 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-04 18:00 Ben Hutchings
2019-06-04 19:02 ` Greg Kroah-Hartman [this message]
2019-06-05 16:16   ` Gen Zhang

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