Messages in this thread | | | Date | Tue, 9 Nov 2021 09:52:58 -0300 | Subject | Re: [PATCH v2 20/22] selftests: futex: Test sys_futex_waitv() timeout | From | André Almeida <> |
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Hi Vasily,
Às 08:18 de 09/11/21, Vasily Gorbik escreveu: > On Thu, Sep 23, 2021 at 02:11:09PM -0300, André Almeida wrote: >> Test if the futex_waitv timeout is working as expected, using the >> supported clockid options. > >> + /* futex_waitv with CLOCK_MONOTONIC */ >> + if (futex_get_abs_timeout(CLOCK_MONOTONIC, &to, timeout_ns)) >> + return RET_FAIL; >> + res = futex_waitv(&waitv, 1, 0, &to, CLOCK_MONOTONIC); >> + test_timeout(res, &ret, "futex_waitv monotonic", ETIMEDOUT); >> + >> + /* futex_waitv with CLOCK_REALTIME */ >> + if (futex_get_abs_timeout(CLOCK_REALTIME, &to, timeout_ns)) >> + return RET_FAIL; >> + res = futex_waitv(&waitv, 1, 0, &to, CLOCK_REALTIME); >> + test_timeout(res, &ret, "futex_waitv realtime", ETIMEDOUT); > > Hi André, > > when built with -m32 and run as compat this two futex_waitv calls hang > on x86 and s390 (noticed while wiring up futex_waitv). The rest of the > futex selftests pass. This suggests some common compat issue? Any ideas?
The issue is that futex_waitv() only accepts struct timespec that uses 64bit members. When using -m32, glibc will give you a 32bit timespec, thus the timeout won't wort. Someday glibc will provide 64bit timespec to 32bit userspace, given that this is affected by y2038 bug.
In previous submissions I added a workaround for that in the selftest[0]. Search for "Y2038 section for 32-bit applications" in that link. I'll submit something like that for futex_waitv() timeout test.
[0] https://lore.kernel.org/lkml/20210709001328.329716-6-andrealmeid@collabora.com/
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