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Re: [PATCH v3 2/2] posix: Implement preadv2 and pwritev2
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: Florian Weimer <fweimer at redhat dot com>, Zack Weinberg <zackw at panix dot com>, "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: Siddhesh Poyarekar <siddhesh at gotplt dot org>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Fri, 2 Jun 2017 11:07:25 -0300
- Subject: Re: [PATCH v3 2/2] posix: Implement preadv2 and pwritev2
- Authentication-results: sourceware.org; auth=none
- References: <1493901791-13438-1-git-send-email-adhemerval.zanella@linaro.org> <1493901791-13438-2-git-send-email-adhemerval.zanella@linaro.org> <8ceeaabf-110f-31fe-516b-18f2fe6710f8@gotplt.org> <7412360d-c776-532b-e22c-dd3f0048cfba@linaro.org> <CAMe9rOpu=yRUr=bHE=h2CJA7e0=U8qz5g5M_PL3GKAtLoUmmJA@mail.gmail.com> <CAKCAbMi95KU=kO1vyj7O4GpHFngOpjDGxCog83nnaYjrRwOF4Q@mail.gmail.com> <7f07b067-a074-d670-88b1-3da917451c71@redhat.com>
On 02/06/2017 10:34, Florian Weimer wrote:
> On 06/02/2017 03:04 PM, Zack Weinberg wrote:
>> I see this as well, for both tst-preadvwritev2 and
>> tst-preadvwritev64v2 on my x86-64 machine (kernel 4.9). Like HJ, if I
>> run the test manually, it succeeds.
>
> I see this on x86-64.
>
> pwritev2(3,
> [{iov_base="\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360",
> iov_len=32},
> {iov_base="\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17"...,
> iov_len=64}], 2, 0, 0x30 /* RWF_??? */) = -1 EOPNOTSUPP (Operation not
> supported)
>
> On a kernel which supports pwritev2 in general. I do not know yet where
> the 0x30 comes from.
>
> Florian
>
This one still puzzles me, on 4.10.0 with gcc 6.3.0 I am seeing:
[...]
[pid 28447] setpgid(0, 0) = 0
[pid 28447] pwritev2(3, [{"\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360", 32}, {"\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17"..., 64}], 2, 0, 0) = 96
[pid 28447] pwritev2(3, [{"\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360", 32}, {"\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17"..., 64}], 2, 96, 0) = 96
[pid 28447] preadv2(3, [{"\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360", 32}, {"\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17"..., 64}], 2, 0, 0) = 96
[pid 28447] preadv2(3, [{"\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360\360", 32}, {"\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17\17"..., 64}], 2, 96, 0) = 96
[pid 28447] getpid() = 28447
[...]
This only issue I can think of is something very fuzzy in test build or a miscompilation.