diff options
| -rw-r--r-- | include/my_pthread.h | 20 | ||||
| -rw-r--r-- | mysys/my_thr_init.c | 39 |
2 files changed, 58 insertions, 1 deletions
diff --git a/include/my_pthread.h b/include/my_pthread.h index b3d84e70d6a..3fdb665d882 100644 --- a/include/my_pthread.h +++ b/include/my_pthread.h @@ -31,8 +31,26 @@ extern "C" { #define EXTERNC #endif /* __cplusplus */ -#if defined(__WIN__) +/* + BUG#24507: Race conditions inside current NPTL pthread_exit() implementation. + + If macro NPTL_PTHREAD_EXIT_HACK is defined then a hack described in the bug + report will be implemented inside my_thread_global_init() in my_thr_init.c. + + This amounts to spawning a dummy thread which does nothing but executes + pthread_exit(0). + + This bug is fixed in version 2.5 of glibc library. + + TODO: Remove this code when fixed versions of glibc6 are in common use. + */ + +#if defined(TARGET_OS_LINUX) && defined(HAVE_NPTL) && \ + defined(__GLIBC__) && ( __GLIBC__ < 2 || __GLIBC__ == 2 && __GLIBC_MINOR__ < 5 ) +#define NPTL_PTHREAD_EXIT_BUG 1 +#endif +#if defined(__WIN__) typedef CRITICAL_SECTION pthread_mutex_t; typedef HANDLE pthread_t; typedef struct thread_attr { diff --git a/mysys/my_thr_init.c b/mysys/my_thr_init.c index c068e28be4b..7b8ef172f85 100644 --- a/mysys/my_thr_init.c +++ b/mysys/my_thr_init.c @@ -47,6 +47,23 @@ pthread_mutexattr_t my_fast_mutexattr; pthread_mutexattr_t my_errorcheck_mutexattr; #endif +#ifdef NPTL_PTHREAD_EXIT_BUG /* see my_pthread.h */ + +/* + Dummy thread spawned in my_thread_global_init() below to avoid + race conditions in NPTL pthread_exit code. +*/ + +static +pthread_handler_t nptl_pthread_exit_hack_handler(void *arg) +{ + /* Do nothing! */ + pthread_exit(0); + return 0; +} + +#endif + /* initialize thread environment @@ -65,6 +82,28 @@ my_bool my_thread_global_init(void) fprintf(stderr,"Can't initialize threads: error %d\n",errno); return 1; } + +#ifdef NPTL_PTHREAD_EXIT_BUG + +/* + BUG#24507: Race conditions inside current NPTL pthread_exit() implementation. + + To avoid a possible segmentation fault during concurrent executions of + pthread_exit(), a dummy thread is spawned which initializes internal variables + of pthread lib. See bug description for thoroughfull explanation. + + TODO: Remove this code when fixed versions of glibc6 are in common use. +*/ + + pthread_t dummy_thread; + pthread_attr_t dummy_thread_attr; + + pthread_attr_init(&dummy_thread_attr); + pthread_attr_setdetachstate(&dummy_thread_attr,PTHREAD_CREATE_DETACHED); + + pthread_create(&dummy_thread,&dummy_thread_attr,nptl_pthread_exit_hack_handler,NULL); + +#endif #ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP /* |