Module: xenomai-jki
Branch: for-forge
Commit: 17ff57ad6c75bdca3a442a8d06ff89510a2e421a
URL:
http://git.xenomai.org/?p=xenomai-jki.git;a=commit;h=17ff57ad6c75bdca3a442a8d06ff89510a2e421a
Author: Jan Kiszka <jan.kis...@siemens.com>
Date: Mon Jan 5 15:48:14 2015 +0100
lib/cobalt: Fix ordering of fork handler
Currently, fork handlers run in more or less random order after
successive forks because pthread_atfork is re-executed for some
handlers. This can cause the heap being unmapped after __init_cobalt was
executed, leaving cobalt_current_window in an invalid state. One result
of this is a crashing sysregd when run as unprivileged user, thus when
it forked fusermount from the forked daemon.
Fix the issue by performing the after-fork work centrally, in a
well-defined order.
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
lib/cobalt/current.c | 8 ++------
lib/cobalt/current.h | 2 ++
lib/cobalt/init.c | 29 +++++++++++++++++++----------
lib/cobalt/internal.h | 2 ++
lib/cobalt/printf.c | 3 +--
lib/cobalt/umm.c | 4 +---
lib/cobalt/umm.h | 2 ++
7 files changed, 29 insertions(+), 21 deletions(-)
diff --git a/lib/cobalt/current.c b/lib/cobalt/current.c
index b7d5b6e..a8bc330 100644
--- a/lib/cobalt/current.c
+++ b/lib/cobalt/current.c
@@ -26,8 +26,6 @@
static DEFINE_PRIVATE_LIST(tsd_hooks);
-static void child_fork_handler(void);
-
#ifdef HAVE_TLS
__thread __attribute__ ((tls_model (CONFIG_XENO_TLS_MODEL)))
@@ -53,7 +51,7 @@ static inline void __cobalt_clear_tsd(void)
static void init_current_keys(void)
{
- pthread_atfork(NULL, NULL, &child_fork_handler);
+ cobalt_current = XN_NO_HANDLE;
}
#else /* !HAVE_TLS */
@@ -85,8 +83,6 @@ static void init_current_keys(void)
if (err)
goto error_exit;
- pthread_atfork(NULL, NULL, &child_fork_handler);
-
err = pthread_key_create(&cobalt_current_window_key, NULL);
if (err) {
error_exit:
@@ -97,7 +93,7 @@ static void init_current_keys(void)
#endif /* !HAVE_TLS */
-static void child_fork_handler(void)
+void cobalt_clear_tsd(void)
{
struct cobalt_tsd_hook *th;
diff --git a/lib/cobalt/current.h b/lib/cobalt/current.h
index 3e28b83..069ee1c 100644
--- a/lib/cobalt/current.h
+++ b/lib/cobalt/current.h
@@ -93,4 +93,6 @@ void cobalt_init_current_keys(void);
void cobalt_set_tsd(__u32 u_winoff);
+void cobalt_clear_tsd(void);
+
#endif /* _LIB_COBALT_CURRENT_H */
diff --git a/lib/cobalt/init.c b/lib/cobalt/init.c
index dfe1150..b7c8f76 100644
--- a/lib/cobalt/init.c
+++ b/lib/cobalt/init.c
@@ -107,6 +107,24 @@ static void low_init(void)
static void __init_cobalt(void);
+static void cobalt_fork_handler(void)
+{
+ cobalt_unmap_umm();
+ cobalt_clear_tsd();
+ cobalt_print_init_atfork();
+#ifdef HAVE_PTHREAD_ATFORK
+ /*
+ * Upon fork, in case the parent required init deferral, this
+ * is the forkee's responsibility to call __libcobalt_init()
+ * for bootstrapping the services the same way. On systems
+ * with no fork() support, clients are not supposed to, well,
+ * fork in the first place, so we don't take any provision for
+ * this event.
+ */
+ __init_cobalt();
+#endif
+}
+
void __libcobalt_init(void)
{
struct sigaction sa;
@@ -118,21 +136,12 @@ void __libcobalt_init(void)
sa.sa_flags = SA_SIGINFO;
sigaction(SIGDEBUG, &sa, &__cobalt_orig_sigdebug);
-#ifdef HAVE_PTHREAD_ATFORK
/*
- * Upon fork, in case the parent required init deferral, this
- * is the forkee's responsibility to call __libcobalt_init()
- * for bootstrapping the services the same way. On systems
- * with no fork() support, clients are not supposed to, well,
- * fork in the first place, so we don't take any provision for
- * this event.
- *
* NOTE: a placeholder for pthread_atfork() may return an
* error status with uClibc, so we don't check the return
* value on purpose.
*/
- pthread_atfork(NULL, NULL, __init_cobalt);
-#endif
+ pthread_atfork(NULL, NULL, cobalt_fork_handler);
if (sizeof(struct cobalt_mutex_shadow) > sizeof(pthread_mutex_t)) {
report_error("sizeof(pthread_mutex_t): %d <"
diff --git a/lib/cobalt/internal.h b/lib/cobalt/internal.h
index c7350be..e126480 100644
--- a/lib/cobalt/internal.h
+++ b/lib/cobalt/internal.h
@@ -45,6 +45,8 @@ void cobalt_thread_init(void);
void cobalt_print_init(void);
+void cobalt_print_init_atfork(void);
+
void cobalt_print_exit(void);
void cobalt_ticks_init(unsigned long long freq);
diff --git a/lib/cobalt/printf.c b/lib/cobalt/printf.c
index e391f96..f19f4ea 100644
--- a/lib/cobalt/printf.c
+++ b/lib/cobalt/printf.c
@@ -670,7 +670,7 @@ static void spawn_printer_thread(void)
pthread_create(&printer_thread, &thattr, printer_loop, NULL);
}
-static void forked_child_init(void)
+void cobalt_print_init_atfork(void)
{
struct print_buffer *my_buffer = pthread_getspecific(buffer_key);
struct print_buffer **pbuffer = &first_buffer;
@@ -791,7 +791,6 @@ void cobalt_print_init(void)
pthread_cond_init(&printer_wakeup, NULL);
spawn_printer_thread();
- pthread_atfork(NULL, NULL, forked_child_init);
rt_print_auto_init(1);
atexit(rt_print_flush_buffers);
diff --git a/lib/cobalt/umm.c b/lib/cobalt/umm.c
index a09b2d6..4a881a3 100644
--- a/lib/cobalt/umm.c
+++ b/lib/cobalt/umm.c
@@ -75,7 +75,7 @@ static void *__map_umm(const char *name, uint32_t *size_r)
#define map_umm(__name, __size_r) __map_umm("/dev/rtdm/" __name, __size_r)
-static void unmap_on_fork(void)
+void cobalt_unmap_umm(void)
{
void *addr;
@@ -121,8 +121,6 @@ static void init_loadup(__u32 vdso_offset)
{
uint32_t size;
- pthread_atfork(NULL, NULL, unmap_on_fork);
-
cobalt_umm_shared = map_umm(COBALT_MEMDEV_SHARED, &size);
if (cobalt_umm_shared == MAP_FAILED) {
report_error("cannot map shared umm area: %s",
diff --git a/lib/cobalt/umm.h b/lib/cobalt/umm.h
index 5647758..b592968 100644
--- a/lib/cobalt/umm.h
+++ b/lib/cobalt/umm.h
@@ -22,6 +22,8 @@
void cobalt_init_umm(__u32 vdso_offset);
+void cobalt_unmap_umm(void);
+
struct xnvdso;
extern struct xnvdso *cobalt_vdso;
_______________________________________________
Xenomai-git mailing list
Xenomai-git@xenomai.org
http://www.xenomai.org/mailman/listinfo/xenomai-git
