Hi,

This should be fixed with "GNU Arm Embedded Toolchain 9-2020-q2" toolchain release.
https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads

Przemyslaw

> -----Original Message-----
> From: <email address hidden> <email address hidden> On Behalf Of
> Bhargav Shah
> Sent: 22 June 2020 10:42
> To: Przemyslaw Wirkus <email address hidden>
> Subject: [Bug 1848002] Re: parallel builds fail on Windows due to bug in
> MinGW-w64 used to build binutils
>
> I am facing this issue with GNU Tools Arm Embedded\9 2019-q4-major.
>
> C:\PROGRA~2\GNUTOO~1\92019-~1\bin\AR17F9~1.EXE: unable to rename
> 'debug\libtest.a'; reason: Permission denied
>
> I hope fix is present in "9 2019-q4-major" version.
>
> Is there any way to verify the fix is present or not?
>
> --
> You received this bug notification because you are a bug assignee.
> https://bugs.launchpad.net/bugs/1848002
>
> Title:
>   parallel builds fail on Windows due to bug in MinGW-w64 used to build
>   binutils
>
> Status in GNU Arm Embedded Toolchain:
>   Fix Released
>
> Bug description:
>   Parallel builds that use GNU ar, objcopy, or strip may fail or
>   generate corrupted files on Windows due to unsafe temporary file
>   handling by the version of MinGW-w64 used to build binutils. The usual
>   symptom are messages like: "unable to rename: <file name>; reason: No
>   such file or directory" or "unable to rename: <file name>; reason:
>   Permission denied", or silent output file corruption. This applies to
>   the latest currently available version of the toolchain
>   (8-2019-q3-update) and at least some previous versions.
>
>   The root cause of the issue is usage of MinGW-w64 that is missing this
>   fix for mkstemp():
>   https://github.com/mirror/mingw-
> w64/commit/76119a8e8938dd23cdb4fe72843723fe4d4cc121
>   #diff-cc1bd3d845f9a0ff2d38778e12b84a17
>
>   The presence of _O_TEMPORARY flag can be verified by disassembling
>   arm-none-eabi-ar:
>
>     3              loc_48f97b:
>     4 0048f97b         mov        dword [esp+0x3c+var_30], 0x180                      ;
> CODE XREF=sub_48f8c0+137
>     5 0048f983         mov        dword [esp+0x3c+var_34], 0x10
>     6 0048f98b         mov        dword [esp+0x3c+var_38], 0x8542
>     7 0048f993         mov        dword [esp+0x3c+var_3C], edi
>     8 0048f996         call       j__sopen                                            ; _sopen
>     9 0048f99b         cmp        eax, 0xffffffff
>
>   0x8542 represents flags passed to _sopen, and 0x40 is _O_TEMPORARY.
>
>   Having _O_TEMPORARY here together with code in binutils that closes
>   the returned file descriptor immediately after it is created
>   (https://sourceware.org/git/gitweb.cgi?p=binutils-
>
> gdb.git;a=blob;f=binutils/bucomm.c;h=06fbc462e242467fe6f15f46e8515d8d
> df6b1456;hb=7e27a9d5f22f9f7ead11738b1546d0b5c737266b#l523)
>   creates a race condition allowing multiple processes to use the same
>   temporary file. Usage of rand() for generating candidate file names in
>   mkstemp() makes this bug relatively easy to reproduce.
>
>   To reproduce the bug try creating multiple archives in the _same_
>   _directory_ using arm-none-eabi-ar in parallel. This may require
>   multiple iterations. I'm attaching a script that can be used to
>   generate build.ninja file that will attempt to create multiple
>   archives in parallel. It requires modification to specify input
>   archives (any should work).
>
>   Fixing this bug should be as easy as rebuilding the toolchain using a
>   newer version of MinGW-w64 (or MinGW).
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/gcc-arm-
> embedded/+bug/1848002/+subscriptions
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