Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1723797

Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement fast refcount overflow protection

From Kees Cook <keescook@chromium.org>
Newsgroups linux.kernel
Subject Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement fast refcount overflow protection
Date 2017-08-31 06:10 +0200
Message-ID <ukoXL-Lg-9@gated-at.bofh.it> (permalink)
References (10 earlier) <ukgGR-3SG-9@gated-at.bofh.it> <ukh9U-44p-3@gated-at.bofh.it> <uknfj-84l-3@gated-at.bofh.it> <uknoZ-8a0-7@gated-at.bofh.it> <ukobo-h0-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


On Wed, Aug 30, 2017 at 8:12 PM, Mike Galbraith <efault@gmx.de> wrote:
> On Wed, 2017-08-30 at 19:27 -0700, Kees Cook wrote:
>
>> Interesting! Can you try with 633547973ffc3 ("net: convert
>> sk_buff.users from atomic_t to refcount_t") reverted? I'll see if
>> running haveged will help me trigger this on my system...
>
> With that (plus 230cd1279d001 fix to it) reverted, vbox boots.

Wonderful! Thank you so much for helping track this down.

So, it seems that sk_buff.users will need some more special attention
before we can convert it to refcount.

x86-refcount will saturate with refcount_dec_and_test() if the result
is negative. But that would mean at least starting at 0. FULL should
have WARNed in this case, so I remain slightly confused why it was
missed by FULL.

Ingo, I'm not sure the best path for this. It seems we need to revert
230cd1279d001 and 633547973ffc3 and then we can restore
ARCH_HAS_REFCOUNT.

-Kees

-- 
Kees Cook
Pixel Security

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-08-29 11:00 +0200
  Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-29 18:00 +0200
    Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-08-29 20:20 +0200
      Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-29 20:50 +0200
        Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-08-30 07:10 +0200
          Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-30 18:40 +0200
            Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-08-30 19:20 +0200
              Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-30 19:40 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-08-30 20:00 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-30 21:20 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-30 21:50 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-08-31 04:20 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-31 04:30 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-08-31 05:20 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-31 06:10 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-31 06:20 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-08-31 06:40 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-08-31 16:00 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-31 19:10 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-08-31 19:30 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-31 20:50 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-09-01 09:00 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-09-01 15:20 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-09-01 19:20 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-09-01 20:00 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-09-01 21:00 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm:  Implement fast refcount overflow protection Mike Galbraith <efault@gmx.de> - 2017-09-01 21:30 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-09-01 21:50 +0200
                Re: tip -ENOBOOT - bisected to locking/refcounts, x86/asm: Implement  fast refcount overflow protection Kees Cook <keescook@chromium.org> - 2017-08-31 21:30 +0200

csiph-web