[PATCH v6] lib/eal: fix segfaults in exiting

[Zhichao Zeng]

The 'eal-intr-thread' is not closed before memory cleanup in the process of
exiting. There is a small chance when 'eal-intr-thread' use some pointers,
meanwhile the memory was just cleaned, which causes segfaults.

This patch closes the 'eal-intr-thread' before memory cleanup in
'rte_eal_cleanup' to avoid segfaults, and adds a flag to avoid executing
'rte_eal_cleanup' in the child process which is forked to execute some
test cases(e.g. debug_autotest of dpdk-test).

Bugzilla ID: 1006
Cc: stable at dpdk.org

Signed-off-by: Zhichao Zeng <zhichaox.zeng at intel.com>

---
v6: use atomic operation
---
v5: simplify patch
---
v4: shorten the prompt message and optimize the commit log
---
v3: fix rte_eal_cleanup crash in debug_autotest
---
v2: add same API for FreeBSD
---
 lib/eal/common/eal_private.h     |  7 +++++++
 lib/eal/freebsd/eal.c            | 20 ++++++++++++++++++++
 lib/eal/freebsd/eal_interrupts.c | 12 ++++++++++++
 lib/eal/linux/eal.c              | 20 ++++++++++++++++++++
 lib/eal/linux/eal_interrupts.c   | 12 ++++++++++++
 5 files changed, 71 insertions(+)

diff --git a/lib/eal/common/eal_private.h b/lib/eal/common/eal_private.h
index 0f4d75bb89..2e3342bd15 100644
--- a/lib/eal/common/eal_private.h
+++ b/lib/eal/common/eal_private.h
@@ -152,6 +152,13 @@ int rte_eal_tailqs_init(void);
  */
 int rte_eal_intr_init(void);
 
+/**
+ * Destroy interrupt handling thread.
+ *
+ * This function is private to EAL.
+ */
+void rte_eal_intr_destroy(void);
+
 /**
  * Close the default log stream
  *
diff --git a/lib/eal/freebsd/eal.c b/lib/eal/freebsd/eal.c
index 1b58cd3da6..0839aa211c 100644
--- a/lib/eal/freebsd/eal.c
+++ b/lib/eal/freebsd/eal.c
@@ -73,6 +73,8 @@ struct lcore_config lcore_config[RTE_MAX_LCORE];
 /* used by rte_rdtsc() */
 int rte_cycles_vmware_tsc_map;
 
+/* mark process is forked */
+static uint32_t forked_flag;
 
 int
 eal_clean_runtime_dir(void)
@@ -575,6 +577,18 @@ static void rte_eal_init_alert(const char *msg)
 	RTE_LOG(ERR, EAL, "%s\n", msg);
 }
 
+static void
+mark_forked(void)
+{
+	__atomic_add_fetch(&forked_flag, 1, __ATOMIC_RELAXED);
+}
+
+static uint32_t
+is_forked(void)
+{
+	return __atomic_load_n(&forked_flag, __ATOMIC_RELAXED);
+}
+
 /* Launch threads, called at application init(). */
 int
 rte_eal_init(int argc, char **argv)
@@ -884,16 +898,22 @@ rte_eal_init(int argc, char **argv)
 
 	eal_mcfg_complete();
 
+	pthread_atfork(NULL, NULL, mark_forked);
+
 	return fctret;
 }
 
 int
 rte_eal_cleanup(void)
 {
+	if (is_forked())
+		return 0;
+
 	struct internal_config *internal_conf =
 		eal_get_internal_configuration();
 	rte_service_finalize();
 	rte_mp_channel_cleanup();
+	rte_eal_intr_destroy();
 	eal_bus_cleanup();
 	rte_trace_save();
 	eal_trace_fini();
diff --git a/lib/eal/freebsd/eal_interrupts.c b/lib/eal/freebsd/eal_interrupts.c
index 9f720bdc8f..cac3859b06 100644
--- a/lib/eal/freebsd/eal_interrupts.c
+++ b/lib/eal/freebsd/eal_interrupts.c
@@ -648,6 +648,18 @@ rte_eal_intr_init(void)
 	return ret;
 }
 
+void
+rte_eal_intr_destroy(void)
+{
+	/* cancel the host thread to wait/handle the interrupt */
+	pthread_cancel(intr_thread);
+	pthread_join(intr_thread, NULL);
+
+	/* close kqueue */
+	close(kq);
+	kq = -1;
+}
+
 int
 rte_intr_rx_ctl(struct rte_intr_handle *intr_handle,
 		int epfd, int op, unsigned int vec, void *data)
diff --git a/lib/eal/linux/eal.c b/lib/eal/linux/eal.c
index e74542fc71..ef15d7e7f0 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -77,6 +77,8 @@ struct lcore_config lcore_config[RTE_MAX_LCORE];
 /* used by rte_rdtsc() */
 int rte_cycles_vmware_tsc_map;
 
+/* mark process is forked */
+static uint32_t forked_flag;
 
 int
 eal_clean_runtime_dir(void)
@@ -955,6 +957,18 @@ eal_worker_thread_create(unsigned int lcore_id)
 	return ret;
 }
 
+static void
+mark_forked(void)
+{
+	__atomic_add_fetch(&forked_flag, 1, __ATOMIC_RELAXED);
+}
+
+static uint32_t
+is_forked(void)
+{
+	return __atomic_load_n(&forked_flag, __ATOMIC_RELAXED);
+}
+
 /* Launch threads, called at application init(). */
 int
 rte_eal_init(int argc, char **argv)
@@ -1325,6 +1339,8 @@ rte_eal_init(int argc, char **argv)
 
 	eal_mcfg_complete();
 
+	pthread_atfork(NULL, NULL, mark_forked);
+
 	return fctret;
 }
 
@@ -1348,6 +1364,9 @@ mark_freeable(const struct rte_memseg_list *msl, const struct rte_memseg *ms,
 int
 rte_eal_cleanup(void)
 {
+	if (is_forked())
+		return 0;
+
 	/* if we're in a primary process, we need to mark hugepages as freeable
 	 * so that finalization can release them back to the system.
 	 */
@@ -1363,6 +1382,7 @@ rte_eal_cleanup(void)
 	vfio_mp_sync_cleanup();
 #endif
 	rte_mp_channel_cleanup();
+	rte_eal_intr_destroy();
 	eal_bus_cleanup();
 	rte_trace_save();
 	eal_trace_fini();
diff --git a/lib/eal/linux/eal_interrupts.c b/lib/eal/linux/eal_interrupts.c
index d52ec8eb4c..7e9853e8e7 100644
--- a/lib/eal/linux/eal_interrupts.c
+++ b/lib/eal/linux/eal_interrupts.c
@@ -1199,6 +1199,18 @@ rte_eal_intr_init(void)
 	return ret;
 }
 
+void
+rte_eal_intr_destroy(void)
+{
+	/* cancel the host thread to wait/handle the interrupt */
+	pthread_cancel(intr_thread);
+	pthread_join(intr_thread, NULL);
+
+	/* close the pipe used by epoll */
+	close(intr_pipe.writefd);
+	close(intr_pipe.readfd);
+}
+
 static void
 eal_intr_proc_rxtx_intr(int fd, const struct rte_intr_handle *intr_handle)
 {
-- 
2.25.1