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Re: [PATCH] kref: Avoid null pointer dereference after WARN

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On Tue, Jun 27, 2017 at 09:06:26AM +0200, Greg Kroah-Hartman wrote:
> I remember one complaint was that WARN_ON was "huge" and this bloated
> the kernel code a lot.  But then that got fixed up.  Is BUG_ON going to
> cause the same complaint again?

Complaint or not, I'm pretty sure using BUG_ON here is the right
behavior. If removing it will result in a null pointer dereference (and
subsequent function call), that's bad news bears, especially on systems
with a zero mmap_min_addr or combined with other bugs.

If somehow a driver manages to pass a NULL as the release function,
something is really messed up and the kernel should "safely" panic
instead.

> 
> thanks,
> 
> greg k-h

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[PATCH] kref: Avoid null pointer dereference after WARN Kees Cook <keescook@chromium.org> - 2017-06-27 06:00 +0200
  Re: [PATCH] kref: Avoid null pointer dereference after WARN Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 09:10 +0200
    Re: [PATCH] kref: Avoid null pointer dereference after WARN "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-06-27 13:10 +0200
      Re: [PATCH] kref: Avoid null pointer dereference after WARN Andi Kleen <ak@linux.intel.com> - 2017-06-27 16:50 +0200
        Re: [PATCH] kref: Avoid null pointer dereference after WARN "Jason A. Donenfeld" <Jason@zx2c4.com> - 2017-06-27 21:20 +0200
          Re: [PATCH] kref: Avoid null pointer dereference after WARN Andi Kleen <ak@linux.intel.com> - 2017-06-27 21:30 +0200
            Re: [PATCH] kref: Avoid null pointer dereference after WARN Michal Hocko <mhocko@kernel.org> - 2017-06-28 13:30 +0200
    Re: [PATCH] kref: Avoid null pointer dereference after WARN Kees Cook <keescook@chromium.org> - 2017-06-27 20:40 +0200
  Re: [PATCH] kref: Avoid null pointer dereference after WARN Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-28 14:00 +0200

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