From: John Stultz <john.stultz@linaro.org>
To: Michal Nazarewicz <mina86@mina86.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Steven Rostedt (Red Hat)" <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] kernel.h: make abs() work with 64-bit types
Date: Thu, 17 Sep 2015 20:12:23 -0700 [thread overview]
Message-ID: <CALAqxLVQv979j-y1RW0Xj2-MsHZjq=-5D0WcfsiZ+hsMc557Aw@mail.gmail.com> (raw)
In-Reply-To: <xa1tzj0mmsh4.fsf@mina86.com>
On Wed, Sep 16, 2015 at 5:57 AM, Michal Nazarewicz <mina86@mina86.com> wrote:
> For 64-bit arguments, abs macro casts it to an int which leads to lost
> precision and may cause incorrect results. To deal with 64-bit types
> abs64 macro has been introduced but still there are places where abs
> macro is used incorrectly.
>
> To deal with the problem, expand abs macro such that it operates on s64
> type when dealing with 64-bit types while still returning long when
> dealing with smaller types.
>
> Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Sorry this is a little late, but I did run this patch through my tests
on a 32bit system (against 4.2, since my localized fix has already
landed in Linus' head) to make sure it resolved the bug I saw and it
did.
So,
Tested-by: John Stultz <john.stultz@linaro.org>
thanks!
-john
next prev parent reply other threads:[~2015-09-18 3:12 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-15 1:05 [RFC][PATCH 0/5] Fixes for abs() usage on 64bit values John Stultz
2015-09-15 1:05 ` [RFC][PATCH 1/5] clocksource: Fix abs() usage w/ " John Stultz
2015-10-02 20:57 ` [tip:timers/urgent] " tip-bot for John Stultz
2015-09-15 1:05 ` [RFC][PATCH 2/5] time: Fix abs() usage with 64-bit values John Stultz
2015-09-15 1:05 ` [RFC][PATCH 3/5] ext4: Fix abs() usage in ext4_mb_check_group_pa John Stultz
2015-09-15 1:05 ` [RFC][PATCH 4/5] percpu: Fix abs() usage in percpu_counter_compare() John Stultz
2015-09-15 1:05 ` [RFC][PATCH 5/5] abs(): Provide build error on passing 64bit value to abs() John Stultz
2015-09-15 5:22 ` Ingo Molnar
2015-09-15 23:52 ` Linus Torvalds
2015-09-16 12:57 ` [PATCH] kernel.h: make abs() work with 64-bit types Michal Nazarewicz
2015-09-18 3:12 ` John Stultz [this message]
2015-09-15 1:49 ` [RFC][PATCH 0/5] Fixes for abs() usage on 64bit values Tejun Heo
2015-09-15 3:27 ` John Stultz
2015-09-15 3:46 ` Tejun Heo
2015-09-15 12:09 ` Jeff Epler
2015-09-15 21:21 ` Andrew Morton
2015-09-15 22:54 ` Michal Nazarewicz
2015-09-15 5:20 ` Ingo Molnar
2015-09-15 23:43 ` Linus Torvalds
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