From: Eric Dumazet <eric.dumazet@gmail.com>
To: Indan Zupancic <indan@nul.nu>
Cc: Will Drewry <wad@chromium.org>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com,
netdev@vger.kernel.org, x86@kernel.org, arnd@arndb.de,
davem@davemloft.net, hpa@zytor.com, mingo@redhat.com,
oleg@redhat.com, peterz@infradead.org, rdunlap@xenotime.net,
mcgrathr@chromium.org, tglx@linutronix.de, luto@mit.edu,
eparis@redhat.com, serge.hallyn@canonical.com, djm@mindrot.org,
scarybeasts@gmail.com, pmoore@redhat.com,
akpm@linux-foundation.org, corbet@lwn.net, markus@chromium.org,
coreyb@linux.vnet.ibm.com, keescook@chromium.org
Subject: Re: [PATCH v14 01/13] sk_run_filter: add BPF_S_ANC_SECCOMP_LD_W
Date: Tue, 13 Mar 2012 10:13:48 -0700 [thread overview]
Message-ID: <1331658828.4449.16.camel@edumazet-glaptop> (raw)
In-Reply-To: <0c55cb258e0b5bbd615923ee2a9f06b9.squirrel@webmail.greenhost.nl>
On Tue, 2012-03-13 at 11:04 +0100, Indan Zupancic wrote:
> Hello,
>
> I made a quick pseudo-patch for BPF JIT support. As far as I can tell,
> the actual code itself is very simple, just:
>
> - bpf_jit_compile(fp);
> + jit = bpf_jit_compile(fp->insns, fp->len, 1);
> + if (jit) {
> + fp->bpf_func = jit;
> + /* Free unused insns memory */
> + newfp = krealloc(fp, sizeof(*fp), GFP_KERNEL);
> + if (newfp)
> + fp = newfp;
> + }
>
> old_fp = rcu_dereference_protected(sk->sk_filter,
> sock_owned_by_user(sk));
Dont mix unrelated changes in a single patch.
Current krealloc() doesnt alloc a new area if the current one is bigger
than 'new_size', but this might change in next kernel versions.
So this part of your patch does nothing.
If it did, this kind of 'optimization' can actually be not good, because
sizeof(*fp) is small enough (less than half cache line size) to trigger
a possible false sharing issue. (other part of the cache line could be
used to hold a often dirtied object)
next prev parent reply other threads:[~2012-03-13 17:13 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-12 21:28 [PATCH v14 01/13] sk_run_filter: add BPF_S_ANC_SECCOMP_LD_W Will Drewry
2012-03-12 21:28 ` [PATCH v14 02/13] net/compat.c,linux/filter.h: share compat_sock_fprog Will Drewry
2012-03-12 21:28 ` [PATCH v14 03/13] seccomp: kill the seccomp_t typedef Will Drewry
2012-03-12 21:28 ` [PATCH v14 04/13] arch/x86: add syscall_get_arch to syscall.h Will Drewry
2012-03-12 21:28 ` [PATCH v14 05/13] asm/syscall.h: add syscall_get_arch Will Drewry
2012-03-12 21:28 ` [PATCH v14 06/13] seccomp: add system call filtering using BPF Will Drewry
2012-03-13 3:33 ` Indan Zupancic
2012-03-13 15:57 ` [kernel-hardening] " Will Drewry
2012-03-12 21:28 ` [PATCH v14 07/13] signal, x86: add SIGSYS info and make it synchronous Will Drewry
2012-03-12 21:28 ` [PATCH v14 08/13] seccomp: add SECCOMP_RET_ERRNO Will Drewry
2012-03-12 21:28 ` [PATCH v14 09/13] seccomp: Add SECCOMP_RET_TRAP Will Drewry
2012-03-12 21:28 ` [PATCH v14 10/13] ptrace,seccomp: Add PTRACE_SECCOMP support Will Drewry
2012-03-14 7:31 ` Indan Zupancic
2012-03-14 15:03 ` [kernel-hardening] " Will Drewry
2012-03-14 15:52 ` Will Drewry
2012-03-15 20:31 ` [PATCH v16 11/13] " Will Drewry
2012-03-12 21:28 ` [PATCH v14 11/13] x86: Enable HAVE_ARCH_SECCOMP_FILTER Will Drewry
2012-03-12 21:28 ` [PATCH v14 12/13] Documentation: prctl/seccomp_filter Will Drewry
2012-03-12 21:28 ` [PATCH v14 13/13] seccomp: remove duplicated failure logging Will Drewry
2012-03-13 3:40 ` [PATCH v14 01/13] sk_run_filter: add BPF_S_ANC_SECCOMP_LD_W Indan Zupancic
2012-03-13 15:40 ` Will Drewry
2012-03-13 10:04 ` Indan Zupancic
2012-03-13 15:43 ` Will Drewry
2012-03-13 17:13 ` Eric Dumazet [this message]
2012-03-14 5:12 ` Indan Zupancic
2012-03-14 5:55 ` Eric Dumazet
2012-03-14 7:59 ` Indan Zupancic
2012-03-14 8:05 ` Eric Dumazet
2012-03-17 10:14 ` Indan Zupancic
2012-03-17 13:49 ` Eric Dumazet
2012-03-18 8:35 ` Indan Zupancic
2012-03-18 12:40 ` [PATCH] net: bpf_jit: fix BPF_S_LDX_B_MSH compilation Eric Dumazet
2012-03-19 21:42 ` David Miller
2012-03-20 0:16 ` [PATCH] net: bpf_jit: Document evilness of negative indirect loads Indan Zupancic
2012-03-18 12:52 ` [PATCH v14 01/13] sk_run_filter: add BPF_S_ANC_SECCOMP_LD_W Eric Dumazet
2012-03-20 2:24 ` [PATCH] net: bpf_jit: Simplify code by always using offset8 or offset32 Indan Zupancic
2012-03-20 2:59 ` Eric Dumazet
2012-03-20 11:33 ` Indan Zupancic
2012-03-20 11:41 ` David Laight
2012-03-20 13:56 ` Eric Dumazet
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1331658828.4449.16.camel@edumazet-glaptop \
--to=eric.dumazet@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=corbet@lwn.net \
--cc=coreyb@linux.vnet.ibm.com \
--cc=davem@davemloft.net \
--cc=djm@mindrot.org \
--cc=eparis@redhat.com \
--cc=hpa@zytor.com \
--cc=indan@nul.nu \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@mit.edu \
--cc=markus@chromium.org \
--cc=mcgrathr@chromium.org \
--cc=mingo@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=pmoore@redhat.com \
--cc=rdunlap@xenotime.net \
--cc=scarybeasts@gmail.com \
--cc=serge.hallyn@canonical.com \
--cc=tglx@linutronix.de \
--cc=wad@chromium.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox