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* dirmngr/ks-engine-hkp.c (select_random_host): Use atomic pass through the host table instead of risking out-of-bounds write. -- Multiple threads may write to hosttable[x]->dead while select_random_host() is running. For example, a housekeeping thread might clear the ->dead bit on some entries, or another connection to dirmngr might manually mark a host as alive. If one or more hosts are resurrected between the two loops over a given table in select_random_host(), then the allocation of tbl might not be large enough, resulting in a write past the end of tbl on the second loop. This change collapses the two loops into a single loop to avoid this discrepancy: each host's "dead" bit is now only checked once. As Werner points out, this isn't currently strictly necessary, since npth will not switch threads unless a blocking system call is made, and no blocking system call is made in these two loops. However, in a subsequent change in this series, we will call a function in this loop, and that function may sometimes write(2), or call other functions, which may themselves block. Keeping this as a single-pass loop avoids the need to keep track of what might block and what might not. Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net> Gbp-Pq: Topic dirmngr-idling Gbp-Pq: Name dirmngr-hkp-Avoid-potential-race-condition-when-some.patch