Merge pull request #7521 from ncfavier/migration-deadlock

Release shared lock before acquiring exclusive lock

1 files changed, 2 insertions, 0 deletions

diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index b67668e52..3bab10af9 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -91,6 +91,7 @@ void migrateCASchema(SQLite& db, Path schemaPath, AutoCloseFD& lockFd)
 
         if (!lockFile(lockFd.get(), ltWrite, false)) {
             printInfo("waiting for exclusive access to the Nix store for ca drvs...");
+            lockFile(lockFd.get(), ltNone, false); // We have acquired a shared lock; release it to prevent deadlocks
             lockFile(lockFd.get(), ltWrite, true);
         }
 
@@ -299,6 +300,7 @@ LocalStore::LocalStore(const Params & params)
 
         if (!lockFile(globalLock.get(), ltWrite, false)) {
             printInfo("waiting for exclusive access to the Nix store...");
+            lockFile(globalLock.get(), ltNone, false); // We have acquired a shared lock; release it to prevent deadlocks
             lockFile(globalLock.get(), ltWrite, true);
         }