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Groups > linux.kernel > #1724514

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 21:30 +0200
Message-ID <ukDk5-1mJ-3@gated-at.bofh.it> (permalink)
References (13 earlier) <uknoZ-8a0-7@gated-at.bofh.it> <ukobo-h0-7@gated-at.bofh.it> <ukoXL-Lg-9@gated-at.bofh.it> <ukp7r-Oj-1@gated-at.bofh.it> <ukyaL-6kL-55@gated-at.bofh.it>
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On Thu, Aug 31, 2017 at 6:58 AM, Mike Galbraith <efault@gmx.de> wrote:
> gdb) list *in6_dev_get+0x10
> 0xffffffff8166d3d0 is in in6_dev_get (./include/net/addrconf.h:318).
> 313     {
> 314             struct inet6_dev *idev;
> 315
> 316             rcu_read_lock();
> 317             idev = rcu_dereference(dev->ip6_ptr);
> 318             if (idev)
> 319                     refcount_inc(&idev->refcnt);
> 320             rcu_read_unlock();
> 321             return idev;
> 322

And this is a completely different refcount from the other that
tripped. This one is quite simple, too, though I see it uses
refcount_dec(), which is a path to saturation. I've sent a patch to
try to clarify this further...

-Kees

-- 
Kees Cook
Pixel Security

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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

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