* ci notify:
> In glibc_check master-aarch64 after:
>
> | commit glibc-2.39.9000-340-g176671f604
> | Author: Carlos Llamas <cmlla...@google.com>
> | Date: Tue Jun 18 10:56:34 2024 +0200
> |
> | linux: add definitions for hugetlb page size encodings
> |
> | A desired hugetlb page size can be encoded in the flags parameter of
> | system calls such as mmap() and shmget(). The Linux UAPI headers have
> | included explicit definitions for these encodings since v4.14.
> |
> | This patch adds these definitions that are used along with MAP_HUGETLB
> | ... 14 lines of the commit log omitted.
>
> FAIL: 1 regressions
>
> regressions.sum:
> === glibc tests ===
>
> Running glibc:misc ...
> FAIL: misc/tst-mman-consts
This must be the error I saw elsewhere:
| First source:
| #define _GNU_SOURCE 1
| #include <sys/mman.h>
|
|
| Second source:
| #define _GNU_SOURCE 1
| #include <linux/mman.h>
|
|
| Only in first source: MAP_ABOVE4G
| Different values for MAP_HUGE_16GB: 2281701376 != -2013265920
The reason is that the kernel changed the definition of MAP_HUGE_16GB.
Older UAPI headers use an undefined expression which is treated by
compilers as a signed int, hence t he discrepancy.
This was fixed on the kernel side in this commit:
commit 710bb68c2e3a24512e2d2bae470960d7488e97b1
Author: Matthias Goergens <matthias.goerg...@gmail.com>
Date: Mon Sep 5 11:19:04 2022 +0800
hugetlb_encode.h: fix undefined behaviour (34 << 26)
Left-shifting past the size of your datatype is undefined behaviour in C.
The literal 34 gets the type `int`, and that one is not big enough to be
left shifted by 26 bits.
An `unsigned` is long enough (on any machine that has at least 32 bits for
their ints.)
For uniformity, we mark all the literals as unsigned. But it's only
really needed for HUGETLB_FLAG_ENCODE_16GB.
Thanks to Randy Dunlap for an initial review and suggestion.
Link:
https://lkml.kernel.org/r/20220905031904.150925-1-matthias.goerg...@gmail.com
Signed-off-by: Matthias Goergens <matthias.goerg...@gmail.com>
Acked-by: Randy Dunlap <rdun...@infradead.org>
Cc: Mike Kravetz <mike.krav...@oracle.com>
Cc: Muchun Song <songmuc...@bytedance.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Not sure what to do about this on the glibc side. Can we waive this in
the CI, or should try to fix up the glibc test?
Thanks,
Florian
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