Messages in this thread | | | Date | Sun, 17 May 2020 12:34:37 -0700 (PDT) | Subject | Re: [PATCH v2] net: revert "net: get rid of an signed integer overflow in ip_idents_reserve()" | From | David Miller <> |
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From: Shaokun Zhang <zhangshaokun@hisilicon.com> Date: Sat, 16 May 2020 11:46:49 +0800
> From: Yuqi Jin <jinyuqi@huawei.com> > > Commit adb03115f459 ("net: get rid of an signed integer overflow in ip_idents_reserve()") > used atomic_cmpxchg to replace "atomic_add_return" inside the function > "ip_idents_reserve". The reason was to avoid UBSAN warning. > However, this change has caused performance degrade and in GCC-8, > fno-strict-overflow is now mapped to -fwrapv -fwrapv-pointer > and signed integer overflow is now undefined by default at all > optimization levels[1]. Moreover, it was a bug in UBSAN vs -fwrapv > /-fno-strict-overflow, so Let's revert it safely. > > [1] https://gcc.gnu.org/gcc-8/changes.html > > Suggested-by: Peter Zijlstra <peterz@infradead.org> > Suggested-by: Eric Dumazet <edumazet@google.com> ... > Signed-off-by: Yuqi Jin <jinyuqi@huawei.com> > Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Applied, thanks.
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