From: Greg KH <gregkh@linuxfoundation.org>
To: "Srivatsa S. Bhat" <srivatsa@csail.mit.edu>
Cc: stable@vger.kernel.org, Gen Zhang <blackgod016574@gmail.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Rob Bradford <robert.bradford@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-efi@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
akaher@vmware.com, srinidhir@vmware.com, bvikas@vmware.com,
amakhalov@vmware.com, srivatsab@vmware.com
Subject: Re: [4.19.y PATCH 1/3] efi/x86/Add missing error handling to old_memmap 1:1 mapping code
Date: Sat, 29 Jun 2019 08:57:21 +0200 [thread overview]
Message-ID: <20190629065721.GA365@kroah.com> (raw)
In-Reply-To: <156174732219.34985.6679541271840078416.stgit@srivatsa-ubuntu>
On Fri, Jun 28, 2019 at 11:42:13AM -0700, Srivatsa S. Bhat wrote:
> From: Gen Zhang <blackgod016574@gmail.com>
>
> commit 4e78921ba4dd0aca1cc89168f45039add4183f8e upstream.
>
> The old_memmap flow in efi_call_phys_prolog() performs numerous memory
> allocations, and either does not check for failure at all, or it does
> but fails to propagate it back to the caller, which may end up calling
> into the firmware with an incomplete 1:1 mapping.
>
> So let's fix this by returning NULL from efi_call_phys_prolog() on
> memory allocation failures only, and by handling this condition in the
> caller. Also, clean up any half baked sets of page tables that we may
> have created before returning with a NULL return value.
>
> Note that any failure at this level will trigger a panic() two levels
> up, so none of this makes a huge difference, but it is a nice cleanup
> nonetheless.
With a description like this, why is this needed in a stable kernel if
it does not really fix anything useful?
thanks,
greg k-h
next prev parent reply other threads:[~2019-06-29 6:57 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-28 18:41 [4.19.y PATCH 0/3] Backported fixes for 4.19 stable tree Srivatsa S. Bhat
2019-06-28 18:42 ` [4.19.y PATCH 1/3] efi/x86/Add missing error handling to old_memmap 1:1 mapping code Srivatsa S. Bhat
2019-06-29 6:57 ` Greg KH [this message]
2019-06-29 8:47 ` Ard Biesheuvel
2019-06-29 8:57 ` Gen Zhang
2019-06-29 9:10 ` Greg KH
2019-06-29 21:11 ` Ard Biesheuvel
2019-06-29 21:49 ` Srivatsa S. Bhat
2019-06-28 18:42 ` [4.19.y PATCH 2/3] ip_sockglue: Fix missing-check bug in ip_ra_control() Srivatsa S. Bhat
2019-06-29 6:58 ` Greg KH
2019-06-28 18:42 ` [4.19.y PATCH 3/3] ipv6_sockglue: Fix a missing-check bug in ip6_ra_control() Srivatsa S. Bhat
2019-06-28 20:44 ` [4.19.y PATCH 0/3] Backported fixes for 4.19 stable tree Sasha Levin
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