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524f89f139
It turns out that using clone() to start a child process is unsafe in a multithreaded program. It can cause the initialisation of a build child process to hang in setgroups(), as seen several times in the build farm: The reason is that Glibc thinks that the other threads of the parent exist in the child, so in setxid_mark_thread() it tries to get a futex that has been acquired by another thread just before the clone(). With fork(), Glibc runs pthread_atfork() handlers that take care of this (in particular, __reclaim_stacks()). But clone() doesn't do that. Fortunately, we can use fork()+unshare() instead of clone() to set up private namespaces. See also https://www.mail-archive.com/lxc-devel@lists.linuxcontainers.org/msg03434.html. |
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| build.cc | ||
| derivations.cc | ||
| derivations.hh | ||
| gc.cc | ||
| globals.cc | ||
| globals.hh | ||
| local-store.cc | ||
| local-store.hh | ||
| local.mk | ||
| misc.cc | ||
| misc.hh | ||
| optimise-store.cc | ||
| pathlocks.cc | ||
| pathlocks.hh | ||
| references.cc | ||
| references.hh | ||
| remote-store.cc | ||
| remote-store.hh | ||
| schema.sql | ||
| store-api.cc | ||
| store-api.hh | ||
| worker-protocol.hh | ||