svn commit: r334104 - in head/sys: netinet sys

[Gleb Smirnoff]

On Thu, May 24, 2018 at 06:44:20AM +0200, Mateusz Guzik wrote:
M> I fundamentally disagree with this part.
M> 
M> If a known value of a given field is needed for assertion purposes, you
M> can add (possibly conditional) code setting this specific value. It
M> probably should not be zero if it can be helped.
M> 
M> Conditional zeroing of the *whole* struct depending on invariants will
M> *hide* uninitialized memory read bugs - production kernel will have
M> whatever it happens to find, while *debug* kernel will guarantee to
M> have all the values zeroed. In fact the flag actively combats redzoning.
M> if the resulting allocation is zeroed, poisoning is actively neutered.
M> But only if debug is enabled.
M> 
M> That said, I find the change harmful.

+1 on fundamentally disagree with M_ZERO_INVARIANTS. It makes the
INVARIANTS-enabled kernels to crash _later_ than production kernels,
since instead of uma_junk it places clean zeroes.

May be changes like that deserve more than a 30 minute time frame for review?

-- 
Gleb Smirnoff