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mdbx: fix thread-local-storage memleak.

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This fix a TLS-memleak for thread from which mdbx_env_close_ex()
has been called. Bug was added by while fixing the
https://github.com/ReOpen/ReOpenLDAP/issues/48

In general we should explicitly free(), because
pthread_key_delete() don't calls a destructor.

Change-Id: Ic55a2348caf3be34b4331d5ad101ea33dbbdfa97
This commit is contained in:
Leo Yuriev 2015-11-16 19:43:15 +03:00
parent cee258fe86
commit 4bdeed9bd3
1 changed files with 14 additions and 11 deletions
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25
mdb.c
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@ -2701,7 +2701,7 @@ mdb_txn_renew0(MDB_txn *txn)
int rc, new_notls = 0; int rc, new_notls = 0;
if ((flags &= MDB_TXN_RDONLY) != 0) { if ((flags &= MDB_TXN_RDONLY) != 0) {
struct MDB_rthc* rthc = NULL; struct MDB_rthc *rthc = NULL;
MDB_reader *r = NULL; MDB_reader *r = NULL;
if (likely(env->me_flags & MDB_ENV_TXKEY)) { if (likely(env->me_flags & MDB_ENV_TXKEY)) {
mdb_assert(env, !(env->me_flags & MDB_NOTLS)); mdb_assert(env, !(env->me_flags & MDB_NOTLS));
@ -4426,15 +4426,16 @@ static pthread_mutex_t mdb_rthc_lock = PTHREAD_MUTEX_INITIALIZER;
/* LY: TODO: Yet another problem is here - segfault in case if a DSO will /* LY: TODO: Yet another problem is here - segfault in case if a DSO will
* be unloaded before a thread would been finished. */ * be unloaded before a thread would been finished. */
static void static void
mdb_env_reader_dest(void *ptr) mdb_env_reader_destr(void *ptr)
{ {
struct MDB_rthc* rthc = ptr; struct MDB_rthc* rthc = ptr;
MDB_reader *reader; MDB_reader *reader;
if (! rthc)
/* LY: paranoia */
return;
mdb_ensure(NULL, pthread_mutex_lock(&mdb_rthc_lock) == 0); mdb_ensure(NULL, pthread_mutex_lock(&mdb_rthc_lock) == 0);
/* LY: Here may be a race with mdb_env_close(),
* see https://github.com/ReOpen/ReOpenLDAP/issues/48
*/
reader = rthc->rc_reader; reader = rthc->rc_reader;
if (reader) { if (reader) {
mdb_ensure(NULL, reader->mr_rthc == rthc); mdb_ensure(NULL, reader->mr_rthc == rthc);
@ -4617,7 +4618,7 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
fcntl(env->me_lfd, F_SETFD, fdflags); fcntl(env->me_lfd, F_SETFD, fdflags);
if (!(env->me_flags & MDB_NOTLS)) { if (!(env->me_flags & MDB_NOTLS)) {
rc = pthread_key_create(&env->me_txkey, mdb_env_reader_dest); rc = pthread_key_create(&env->me_txkey, mdb_env_reader_destr);
if (rc) if (rc)
goto fail; goto fail;
env->me_flags |= MDB_ENV_TXKEY; env->me_flags |= MDB_ENV_TXKEY;
@ -4910,12 +4911,14 @@ mdb_env_close0(MDB_env *env)
mdb_ensure(env, pthread_mutex_lock(&mdb_rthc_lock) == 0); mdb_ensure(env, pthread_mutex_lock(&mdb_rthc_lock) == 0);
for (i = env->me_close_readers; --i >= 0; ) { for (i = env->me_close_readers; --i >= 0; ) {
MDB_reader *reader = &env->me_txns->mti_readers[i]; MDB_reader *reader = &env->me_txns->mti_readers[i];
if (reader->mr_pid == pid) { if (reader->mr_pid == pid) {
mdb_ensure(env, reader->mr_rthc->rc_reader == reader); struct MDB_rthc *rthc = reader->mr_rthc;
reader->mr_rthc->rc_reader = NULL; if (rthc) {
reader->mr_rthc = NULL; mdb_ensure(env, rthc->rc_reader == reader);
mdb_compiler_barrier(); rthc->rc_reader = NULL;
reader->mr_rthc = NULL;
free(rthc);
}
reader->mr_pid = 0; reader->mr_pid = 0;
} }
} }