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From: "slyfox at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug other/109898] New: 'make install -j' sometimes corrupts 'dir' file for .info files due to parallel 'install-info' calls
Date: Wed, 17 May 2023 20:40:14 +0000	[thread overview]
Message-ID: <bug-109898-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109898

            Bug ID: 109898
           Summary: 'make install -j' sometimes corrupts 'dir' file for
                    .info files due to parallel 'install-info' calls
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: slyfox at gcc dot gnu.org
  Target Milestone: ---

In https://github.com/NixOS/nixpkgs/issues/229470 Arnout Engelen noticed that
'make install -j' sometimes installs incomplete '$prefix/share/info/dir' file.

This happens because 'make install-info' when running in parallel is executing
equivalent of:

if /<<NIX>>/bash-5.2-p15/bin/bash -c 'install-info --version' >/dev/null 2>&1;
then \
    install-info
--dir-file=/<<NIX>>/x86_64-unknown-linux-musl-stage-static-gcc-14.0.0/share/info/dir
/<<NIX>>/x86_64-unknown-linux-musl-stage-static-gcc-14.0.0/share/info/gcc.info;
\
if /<<NIX>>/bash-5.2-p15/bin/bash -c 'install-info --version' >/dev/null 2>&1;
then \
    install-info
--dir-file=/<<NIX>>/x86_64-unknown-linux-musl-stage-static-gcc-14.0.0/share/info/dir
/<<NIX>>/x86_64-unknown-linux-musl-stage-static-gcc-14.0.0/share/info/gccinstall.info;
\
if /<<NIX>>/bash-5.2-p15/bin/bash -c 'install-info --version' >/dev/null 2>&1;
then \
    install-info
--dir-file=/<<NIX>>/x86_64-unknown-linux-musl-stage-static-gcc-14.0.0/share/info/dir
/<<NIX>>/x86_64-unknown-linux-musl-stage-static-gcc-14.0.0/share/info/cppinternals.info;
\
if /<<NIX>>/bash-5.2-p15/bin/bash -c 'install-info --version' >/dev/null 2>&1;
then \
    install-info
--dir-file=/<<NIX>>/x86_64-unknown-linux-musl-stage-static-gcc-14.0.0/share/info/dir
/<<NIX>>/x86_64-unknown-linux-musl-stage-static-gcc-14.0.0/share/info/cpp.info;
\
if /<<NIX>>/bash-5.2-p15/bin/bash -c 'install-info --version' >/dev/null 2>&1;
then \
    install-info
--dir-file=/<<NIX>>/x86_64-unknown-linux-musl-stage-static-gcc-14.0.0/share/info/dir
/<<NIX>>/x86_64-unknown-linux-musl-stage-static-gcc-14.0.0/share/info/gccint.info;
\

On it's own 'install-info' does not lock $prefix/share/info/dir file
atomically. As a result multiple parallel executions of 'install-info' compete
and occasionally throw away work of one another.

Right now `nixpkgs` works it around as
https://github.com/NixOS/nixpkgs/pull/229898:

--- gcc-12.2.0/gcc/Makefile.in  2022-08-19 10:09:52.280658631 +0200
+++ gcc-12.2.0-new/gcc/Makefile.in      2023-05-04 14:35:44.401420184 +0200
@@ -3781,6 +3781,11 @@
          fi; \
        fi

+# We don't care about the order in which the info files are built, but
+# install-info doesn't support multiple parallel invocations writing to
+# the same `dir-file`, so we have to disable parallelism for that reason:
+.NOTPARALLEL: install-info
+
 # Install the info files.
 # $(INSTALL_DATA) might be a relative pathname, so we can't cd into srcdir
 # to do the install.

It might not be enough to handle language-specific 'install-info' targets.

What would be the best way to handle this race condition?

             reply	other threads:[~2023-05-17 20:40 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-17 20:40 slyfox at gcc dot gnu.org [this message]
2023-05-18  6:23 ` [Bug other/109898] " rguenth at gcc dot gnu.org
2023-05-18  8:36 ` redi at gcc dot gnu.org
2023-05-18 19:35 ` slyfox at gcc dot gnu.org
2023-05-19  9:29 ` redi at gcc dot gnu.org
2023-05-19  9:52 ` jakub at gcc dot gnu.org

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