The previous code had some errors that would be triggered on platforms
without stdatomics but with support for xadd assembly instruction.
The major error was combining two uint32_t values from the
multifield atomic structure using a logical AND '&&' instead of a
bitwise OR '|'.
Some preprocessor rules were redundant and thus were simplified,
regarding the definition of ISC_STATS_USEMULTIFIELDS macro.
Correctly changed rwlock type to read on isc_stats_get_counter.
This prevents races on fctx->client whenever a new fetch joins a existing
fetch (by calling fctx_join) as it is now invariant for the active life of
fctx.
(cherry picked from commit 9ca6ad6311)
xmlInitThreads() and xmlCleanupThreads() are called from within
ns_statschannels_configure() and ns_statschannels_shutdown(),
respectively. Both of these functions are executed by worker threads,
not the main named thread. This causes ASAN to report memory leaks like
the following one upon shutdown (as long as named is asked to produce
any XML output over its configured statistics channels during its
lifetime):
Direct leak of 968 byte(s) in 1 object(s) allocated from:
#0 0x7f677c249cd8 in __interceptor_calloc /build/gcc/src/gcc/libsanitizer/asan/asan_malloc_linux.cc:153
#1 0x7f677bc1838f in xmlGetGlobalState (/usr/lib/libxml2.so.2+0xa838f)
The data mentioned in the above report is a libxml2 state structure
stored as thread-specific data. Such chunks of memory are automatically
released (by a destructor passed to pthread_key_create() by libxml2)
whenever a thread that allocated a given chunk exits. However, if
xmlCleanupThreads() is called by a given thread before it exits, the
destructor will not be invoked (due to xmlCleanupThreads() calling
pthread_key_delete()) and ASAN will report a memory leak. Thus,
xmlInitThreads() and xmlCleanupThreads() must not be called from worker
threads. Since xmlInitThreads() must be called on Windows in order for
libxml2 to work at all, move xmlInitThreads() and xmlCleanupThreads()
calls to the main named thread (which does not produce any XML output
itself) in order to prevent the memory leak from being reported by ASAN.
(cherry picked from commit b425b5d56e)
Loaded GeoIP2 databases are only released when named is shut down, but
not during server reconfiguration. This causes memory to be leaked
every time "rndc reconfig" or "rndc reload" is used, as long as any
GeoIP2 database is in use. Fix by releasing any loaded GeoIP2 databases
before reloading them. Do not call dns_geoip_shutdown() until server
shutdown as that function releases the memory context used for caching
GeoIP2 lookup results.
(cherry picked from commit 670afbe84a)
When loading the configuration fails, there might be already other tasks
running and calling OpenSSL library functions. The OpenSSL on_exit
handler is called when exiting the main process and there's a timing
race between the on_exit function that destroys OpenSSL allocated
resources (threads, locks, ...) and other tasks accessing the very same
resources leading to a crash in the system threading library. Therefore,
the fatal() function needs to request exlusive access to the task
manager to finish the already running tasks and exit only when no other
tasks are running.
(cherry picked from commit 952d7fde63)
