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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Jeremy Kerr <jk@ozlabs.org>, Arnd Bergmann <arnd@arndb.de>,
	Oleg Nesterov <oleg@redhat.com>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: remove set_fs calls from the coredump code v6
Date: Tue, 5 May 2020 09:52:04 -0700	[thread overview]
Message-ID: <CAHk-=wgrHhaM1XCB=E3Zp2Br8E5c_kmVUTd5y06xh5sev5nRMA@mail.gmail.com> (raw)
In-Reply-To: <20200505101256.3121270-1-hch@lst.de>

On Tue, May 5, 2020 at 3:13 AM Christoph Hellwig <hch@lst.de> wrote:
>
> this series gets rid of playing with the address limit in the exec and
> coredump code.  Most of this was fairly trivial, the biggest changes are
> those to the spufs coredump code.

Ack, nice, and looks good.

The only part I dislike is how we have that 'struct compat_siginfo' on
the stack, which is a huge waste (most of it is the nasty padding to
128 bytes).

But that's not new, I only reacted to it because the code moved a bit.
We cleaned up the regular siginfo to not have the padding in the
kernel (and by "we" I mean "Eric Biederman did it after some prodding
as part of his siginfo cleanups" - see commit 4ce5f9c9e754 "signal:
Use a smaller struct siginfo in the kernel"),  and I wonder if we
could do something similar with that compat thing.

128 bytes of wasted kernel stack isn't the end of the world, but it's
sad when the *actual* data is only 32 bytes or so.

                Linus

WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Arnd Bergmann <arnd@arndb.de>, Jeremy Kerr <jk@ozlabs.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>
Subject: Re: remove set_fs calls from the coredump code v6
Date: Tue, 5 May 2020 09:52:04 -0700	[thread overview]
Message-ID: <CAHk-=wgrHhaM1XCB=E3Zp2Br8E5c_kmVUTd5y06xh5sev5nRMA@mail.gmail.com> (raw)
In-Reply-To: <20200505101256.3121270-1-hch@lst.de>

On Tue, May 5, 2020 at 3:13 AM Christoph Hellwig <hch@lst.de> wrote:
>
> this series gets rid of playing with the address limit in the exec and
> coredump code.  Most of this was fairly trivial, the biggest changes are
> those to the spufs coredump code.

Ack, nice, and looks good.

The only part I dislike is how we have that 'struct compat_siginfo' on
the stack, which is a huge waste (most of it is the nasty padding to
128 bytes).

But that's not new, I only reacted to it because the code moved a bit.
We cleaned up the regular siginfo to not have the padding in the
kernel (and by "we" I mean "Eric Biederman did it after some prodding
as part of his siginfo cleanups" - see commit 4ce5f9c9e754 "signal:
Use a smaller struct siginfo in the kernel"),  and I wonder if we
could do something similar with that compat thing.

128 bytes of wasted kernel stack isn't the end of the world, but it's
sad when the *actual* data is only 32 bytes or so.

                Linus

  parent reply	other threads:[~2020-05-05 16:52 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-05 10:12 remove set_fs calls from the coredump code v6 Christoph Hellwig
2020-05-05 10:12 ` Christoph Hellwig
2020-05-05 10:12 ` [PATCH 1/7] powerpc/spufs: fix copy_to_user while atomic Christoph Hellwig
2020-05-05 10:12   ` Christoph Hellwig
2020-05-05 10:12 ` [PATCH 2/7] powerpc/spufs: stop using access_ok Christoph Hellwig
2020-05-05 10:12   ` Christoph Hellwig
2020-05-05 10:12 ` [PATCH 3/7] powerpc/spufs: simplify spufs core dumping Christoph Hellwig
2020-05-05 10:12   ` Christoph Hellwig
2020-05-05 10:12 ` [PATCH 4/7] signal: refactor copy_siginfo_to_user32 Christoph Hellwig
2020-05-05 10:12   ` Christoph Hellwig
2020-05-05 10:12 ` [PATCH 5/7] binfmt_elf: remove the set_fs in fill_siginfo_note Christoph Hellwig
2020-05-05 10:12   ` Christoph Hellwig
2020-05-05 10:12 ` [PATCH 6/7] binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dump Christoph Hellwig
2020-05-05 10:12   ` Christoph Hellwig
2020-05-05 10:12 ` [PATCH 7/7] binfmt_elf_fdpic: remove the set_fs(KERNEL_DS) in elf_fdpic_core_dump Christoph Hellwig
2020-05-05 10:12   ` Christoph Hellwig
2020-05-05 16:52 ` Linus Torvalds [this message]
2020-05-05 16:52   ` remove set_fs calls from the coredump code v6 Linus Torvalds
2020-05-05 20:28   ` Eric W. Biederman
2020-05-05 20:28     ` Eric W. Biederman
2020-05-06  6:31     ` Christoph Hellwig
2020-05-06  6:31       ` Christoph Hellwig
2020-05-06 15:44       ` Eric W. Biederman
2020-05-06 15:44         ` Eric W. Biederman
2020-05-05 20:34 ` Al Viro
2020-05-05 20:34   ` Al Viro
2020-05-05 20:42   ` Christoph Hellwig
2020-05-05 20:42     ` Christoph Hellwig
2020-05-05 20:47     ` Al Viro
2020-05-05 20:47       ` Al Viro

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