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From: Richard Henderson <richard.henderson@linaro.org>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	qemu-devel@nongnu.org, qemu-block@nongnu.org
Subject: Re: [PATCH 4/9] util/oslib-win32: Return NULL on qemu_try_memalign() with zero size
Date: Sun, 27 Feb 2022 08:36:50 -1000	[thread overview]
Message-ID: <91cc02c4-8ea5-23e7-7384-6c6b2c8e12b5@linaro.org> (raw)
In-Reply-To: <CAFEAcA8J+pYScRp3KJAb0iLuS65nYVDYkiWPARAT5Ot9299VqA@mail.gmail.com>

On 2/27/22 02:54, Peter Maydell wrote:
>>> +    if (size) {
>>> +        ptr = _aligned_malloc(size, alignment);
>>> +    } else {
>>> +        ptr = NULL;
>>> +    }
>>
>> Oh, should we set errno to something here?
>> Otherwise a random value will be used by qemu_memalign.
> 
> Yeah, I guess so, though the errno to use isn't obvious. Maybe EINVAL?
> 
> The alternative would be to try to audit all the callsites to
> confirm they don't ever try to allocate 0 bytes and then have
> the assert for both Windows and POSIX versions...

Alternately, force size == 1, so that we always get a non-NULL value that can be freed. 
That's a change on the POSIX side as well, of course.


r~



  reply	other threads:[~2022-02-27 18:46 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-26 18:07 [PATCH 0/9] Cleanup of qemu_oom_check() and qemu_memalign() Peter Maydell
2022-02-26 18:07 ` [PATCH 1/9] hw/usb/redirect.c: Stop using qemu_oom_check() Peter Maydell
2022-02-26 18:41   ` Peter Maydell
2022-02-27  0:26   ` Richard Henderson
2022-03-01  0:00   ` Philippe Mathieu-Daudé
2022-03-02 16:30   ` Eric Blake
2022-03-02 17:03     ` Peter Maydell
2022-02-26 18:07 ` [PATCH 2/9] util: Make qemu_oom_check() a static function Peter Maydell
2022-02-27  0:27   ` Richard Henderson
2022-03-01  0:00   ` Philippe Mathieu-Daudé
2022-02-26 18:07 ` [PATCH 3/9] util: Unify implementations of qemu_memalign() Peter Maydell
2022-02-27  0:29   ` Richard Henderson
2022-02-26 18:07 ` [PATCH 4/9] util/oslib-win32: Return NULL on qemu_try_memalign() with zero size Peter Maydell
2022-02-27  0:46   ` Richard Henderson
2022-02-27  0:56   ` Richard Henderson
2022-02-27 12:54     ` Peter Maydell
2022-02-27 18:36       ` Richard Henderson [this message]
2022-03-03 16:55         ` Peter Maydell
2022-03-03 23:02           ` Richard Henderson
2022-03-04 10:20             ` Peter Maydell
2022-02-26 18:07 ` [PATCH 5/9] meson.build: Don't misdetect posix_memalign() on Windows Peter Maydell
2022-02-27  0:52   ` Richard Henderson
2022-02-26 18:07 ` [PATCH 6/9] util: Share qemu_try_memalign() implementation between POSIX and Windows Peter Maydell
2022-02-27  0:56   ` Richard Henderson
2022-02-26 18:07 ` [PATCH 7/9] util: Use meson checks for valloc() and memalign() presence Peter Maydell
2022-02-27  0:58   ` Richard Henderson
2022-02-28 23:56   ` Philippe Mathieu-Daudé
2022-02-26 18:07 ` [PATCH 8/9] util: Put qemu_vfree() in memalign.c Peter Maydell
2022-02-27  1:05   ` Richard Henderson
2022-02-26 18:07 ` [PATCH 9/9] osdep: Move memalign-related functions to their own header Peter Maydell
2022-02-27  1:13   ` Richard Henderson
2022-02-28 23:58   ` Philippe Mathieu-Daudé

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