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| author | Eelco Dolstra <edolstra@gmail.com> | 2020-10-06 18:52:46 +0200 |
|---|---|---|
| committer | Eelco Dolstra <edolstra@gmail.com> | 2020-10-06 18:57:23 +0200 |
| commit | d761485010cc9d071da17a5d90cf4126a4bf499d (patch) | |
| tree | b19f2a335debafd3792c7ff73cd4834bb68db9c3 /src/libstore | |
| parent | ad143c5b3b7e713b89f0437ce17c20ac642ca530 (diff) | |
Prevent a deadlock when user namespace setup fails
Observed on Centos 7 when user namespaces are disabled:
DerivationGoal::startBuilder() throws an exception, ~DerivationGoal()
waits for the child process to exit, but the child process hangs
forever in drainFD(userNamespaceSync.readSide.get()) in
DerivationGoal::runChild(). Not sure why the SIGKILL doesn't get
through.
Issue #4092.
Diffstat (limited to 'src/libstore')
| -rw-r--r-- | src/libstore/build.cc | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/src/libstore/build.cc b/src/libstore/build.cc index 87e01a378..9497e7b3e 100644 --- a/src/libstore/build.cc +++ b/src/libstore/build.cc @@ -2686,6 +2686,12 @@ void DerivationGoal::startBuilder() userNamespaceSync.readSide = -1; + /* Close the write side to prevent runChild() from hanging + reading from this. */ + Finally cleanup([&]() { + userNamespaceSync.writeSide = -1; + }); + pid_t tmp; if (!string2Int<pid_t>(readLine(builderOut.readSide.get()), tmp)) abort(); pid = tmp; @@ -2712,7 +2718,6 @@ void DerivationGoal::startBuilder() /* Signal the builder that we've updated its user namespace. */ writeFull(userNamespaceSync.writeSide.get(), "1"); - userNamespaceSync.writeSide = -1; } else #endif |