[PATCH v5] lib/eal: fix segfaults in exiting

[PATCH v5] 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 that the 'eal-intr-thread' is about to use
some pointers, the memory was just cleaned, which causes segfaults
caught by ASan.

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 execut some
test cases(e.g. debug_autotest of dpdk-test).

Bugzilla ID: 1006
Cc: stable@dpdk.org

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

---
v2: add same API for FreeBSD
---
v3: fix rte_eal_cleanup crash in debug_autotest
---
v4: shorten the prompt message and optimize the commit log
---
v5: simplify patch
---
 lib/eal/common/eal_private.h     |  7 +++++++
 lib/eal/freebsd/eal.c            | 13 +++++++++++++
 lib/eal/freebsd/eal_interrupts.c | 12 ++++++++++++
 lib/eal/linux/eal.c              | 13 +++++++++++++
 lib/eal/linux/eal_interrupts.c   | 12 ++++++++++++
 5 files changed, 57 insertions(+)

diff --git a/lib/eal/common/eal_private.h b/lib/eal/common/eal_private.h
index 44d14241f0..7adf41b7d7 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 26fbc91b26..f27c1d9f97 100644
--- a/lib/eal/freebsd/eal.c
+++ b/lib/eal/freebsd/eal.c
@@ -72,6 +72,8 @@ struct lcore_config lcore_config[RTE_MAX_LCORE];
 /* used by rte_rdtsc() */
 int rte_cycles_vmware_tsc_map;
 
+/* used to judge if is forked */
+static int is_forked;
 
 int
 eal_clean_runtime_dir(void)
@@ -574,6 +576,11 @@ static void rte_eal_init_alert(const char *msg)
 	RTE_LOG(ERR, EAL, "%s\n", msg);
 }
 
+static void mark_forked(void)
+{
+	is_forked++;
+}
+
 /* Launch threads, called at application init(). */
 int
 rte_eal_init(int argc, char **argv)
@@ -883,16 +890,22 @@ 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();
 	rte_trace_save();
 	eal_trace_fini();
 	/* after this point, any DPDK pointers will become dangling */
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 37d29643a5..ea38ec183d 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -76,6 +76,8 @@ struct lcore_config lcore_config[RTE_MAX_LCORE];
 /* used by rte_rdtsc() */
 int rte_cycles_vmware_tsc_map;
 
+/* used to judge if is forked */
+static int is_forked;
 
 int
 eal_clean_runtime_dir(void)
@@ -954,6 +956,11 @@ eal_worker_thread_create(unsigned int lcore_id)
 	return ret;
 }
 
+static void mark_forked(void)
+{
+	is_forked++;
+}
+
 /* Launch threads, called at application init(). */
 int
 rte_eal_init(int argc, char **argv)
@@ -1324,6 +1331,8 @@ rte_eal_init(int argc, char **argv)
 
 	eal_mcfg_complete();
 
+	pthread_atfork(NULL, NULL, mark_forked);
+
 	return fctret;
 }
 
@@ -1347,6 +1356,9 @@ 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.
 	 */
@@ -1362,6 +1374,7 @@ rte_eal_cleanup(void)
 	vfio_mp_sync_cleanup();
 #endif
 	rte_mp_channel_cleanup();
+	rte_eal_intr_destroy();
 	rte_trace_save();
 	eal_trace_fini();
 	/* after this point, any DPDK pointers will become dangling */
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

[PATCH v4] lib/eal: fix segfaults due to thread exit order

[zhichaox.zeng]

From: Zhichao Zeng <zhichaox.zeng@intel.com>

The eal-intr-thread is not closed before memory cleanup in the
process of exiting. There is a small probability that when the
eal-intr-thread is about to use some pointers, the memory were
just cleaned, which cause the segment fault error caught by ASan.

This patch close the eal-intr-thread before memory cleanup when
exiting to avoid segment fault. And add some atomic operations
to avoid executing rte_eal_cleanup in the child process spawned
by fork() in some test cases, e.g. debug_autotest of dpdk-test.

Cc: stable@dpdk.org

---
v2:
add the same API for FreeBSD
---
v3:
fix rte_eal_cleanup crash in debug_autotest
---
v4:
shorten the prompt message and optimize the commit log

Suggested-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Zhichao Zeng <zhichaox.zeng@intel.com>
---
 lib/eal/common/eal_private.h     |  7 +++++++
 lib/eal/freebsd/eal.c            | 21 ++++++++++++++++++++-
 lib/eal/freebsd/eal_interrupts.c | 12 ++++++++++++
 lib/eal/linux/eal.c              | 20 +++++++++++++++++++-
 lib/eal/linux/eal_interrupts.c   | 12 ++++++++++++
 5 files changed, 70 insertions(+), 2 deletions(-)

diff --git a/lib/eal/common/eal_private.h b/lib/eal/common/eal_private.h
index 44d14241f0..7adf41b7d7 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 a6b20960f2..4882f27abd 100644
--- a/lib/eal/freebsd/eal.c
+++ b/lib/eal/freebsd/eal.c
@@ -72,6 +72,8 @@ struct lcore_config lcore_config[RTE_MAX_LCORE];
 /* used by rte_rdtsc() */
 int rte_cycles_vmware_tsc_map;
 
+/* used to judge the running status of the eal */
+static uint32_t run_once;
 
 int
 eal_clean_runtime_dir(void)
@@ -574,12 +576,22 @@ static void rte_eal_init_alert(const char *msg)
 	RTE_LOG(ERR, EAL, "%s\n", msg);
 }
 
+static void warn_parent(void)
+{
+	RTE_LOG(WARNING, EAL, "DPDK won't work in the child process\n");
+}
+
+static void scratch_child(void)
+{
+	/* Scratch run_once so that a call to rte_eal_cleanup won't crash... */
+	__atomic_store_n(&run_once, 0, __ATOMIC_RELAXED);
+}
+
 /* Launch threads, called at application init(). */
 int
 rte_eal_init(int argc, char **argv)
 {
 	int i, fctret, ret;
-	static uint32_t run_once;
 	uint32_t has_run = 0;
 	char cpuset[RTE_CPU_AFFINITY_STR_LEN];
 	char thread_name[RTE_MAX_THREAD_NAME_LEN];
@@ -883,6 +895,8 @@ rte_eal_init(int argc, char **argv)
 
 	eal_mcfg_complete();
 
+	pthread_atfork(NULL, warn_parent, scratch_child);
+
 	return fctret;
 }
 
@@ -891,8 +905,13 @@ rte_eal_cleanup(void)
 {
 	struct internal_config *internal_conf =
 		eal_get_internal_configuration();
+
+	if (__atomic_load_n(&run_once, __ATOMIC_RELAXED) == 0)
+		return 0;
+
 	rte_service_finalize();
 	rte_mp_channel_cleanup();
+	rte_eal_intr_destroy();
 	/* after this point, any DPDK pointers will become dangling */
 	rte_eal_memory_detach();
 	rte_eal_alarm_cleanup();
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 1ef263434a..effebb33a6 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -76,6 +76,8 @@ struct lcore_config lcore_config[RTE_MAX_LCORE];
 /* used by rte_rdtsc() */
 int rte_cycles_vmware_tsc_map;
 
+/* used to judge the running status of the eal */
+static uint32_t run_once;
 
 int
 eal_clean_runtime_dir(void)
@@ -857,12 +859,22 @@ is_iommu_enabled(void)
 	return n > 2;
 }
 
+static void warn_parent(void)
+{
+	RTE_LOG(WARNING, EAL, "DPDK won't work in the child process\n");
+}
+
+static void scratch_child(void)
+{
+	/* Scratch run_once so that a call to rte_eal_cleanup won't crash... */
+	__atomic_store_n(&run_once, 0, __ATOMIC_RELAXED);
+}
+
 /* Launch threads, called at application init(). */
 int
 rte_eal_init(int argc, char **argv)
 {
 	int i, fctret, ret;
-	static uint32_t run_once;
 	uint32_t has_run = 0;
 	const char *p;
 	static char logid[PATH_MAX];
@@ -1228,6 +1240,8 @@ rte_eal_init(int argc, char **argv)
 
 	eal_mcfg_complete();
 
+	pthread_atfork(NULL, warn_parent, scratch_child);
+
 	return fctret;
 }
 
@@ -1257,6 +1271,9 @@ rte_eal_cleanup(void)
 	struct internal_config *internal_conf =
 		eal_get_internal_configuration();
 
+	if (__atomic_load_n(&run_once, __ATOMIC_RELAXED) == 0)
+		return 0;
+
 	if (rte_eal_process_type() == RTE_PROC_PRIMARY &&
 			internal_conf->hugepage_file.unlink_existing)
 		rte_memseg_walk(mark_freeable, NULL);
@@ -1266,6 +1283,7 @@ rte_eal_cleanup(void)
 	vfio_mp_sync_cleanup();
 #endif
 	rte_mp_channel_cleanup();
+	rte_eal_intr_destroy();
 	/* after this point, any DPDK pointers will become dangling */
 	rte_eal_memory_detach();
 	eal_mp_dev_hotplug_cleanup();
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

[PATCH v5] 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 that the 'eal-intr-thread' is about to use
some pointers, the memory was just cleaned, which causes segfaults
caught by ASan.

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 execut some
test cases(e.g. debug_autotest of dpdk-test).

Bugzilla ID: 1006
Cc: stable@dpdk.org

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

---
v2: add same API for FreeBSD
---
v3: fix rte_eal_cleanup crash in debug_autotest
---
v4: shorten the prompt message and optimize the commit log
---
v5: simplify patch
---
 lib/eal/common/eal_private.h     |  7 +++++++
 lib/eal/freebsd/eal.c            | 13 +++++++++++++
 lib/eal/freebsd/eal_interrupts.c | 12 ++++++++++++
 lib/eal/linux/eal.c              | 13 +++++++++++++
 lib/eal/linux/eal_interrupts.c   | 12 ++++++++++++
 5 files changed, 57 insertions(+)

diff --git a/lib/eal/common/eal_private.h b/lib/eal/common/eal_private.h
index 44d14241f0..7adf41b7d7 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 26fbc91b26..f27c1d9f97 100644
--- a/lib/eal/freebsd/eal.c
+++ b/lib/eal/freebsd/eal.c
@@ -72,6 +72,8 @@ struct lcore_config lcore_config[RTE_MAX_LCORE];
 /* used by rte_rdtsc() */
 int rte_cycles_vmware_tsc_map;
 
+/* used to judge if is forked */
+static int is_forked;
 
 int
 eal_clean_runtime_dir(void)
@@ -574,6 +576,11 @@ static void rte_eal_init_alert(const char *msg)
 	RTE_LOG(ERR, EAL, "%s\n", msg);
 }
 
+static void mark_forked(void)
+{
+	is_forked++;
+}
+
 /* Launch threads, called at application init(). */
 int
 rte_eal_init(int argc, char **argv)
@@ -883,16 +890,22 @@ 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();
 	rte_trace_save();
 	eal_trace_fini();
 	/* after this point, any DPDK pointers will become dangling */
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 37d29643a5..ea38ec183d 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -76,6 +76,8 @@ struct lcore_config lcore_config[RTE_MAX_LCORE];
 /* used by rte_rdtsc() */
 int rte_cycles_vmware_tsc_map;
 
+/* used to judge if is forked */
+static int is_forked;
 
 int
 eal_clean_runtime_dir(void)
@@ -954,6 +956,11 @@ eal_worker_thread_create(unsigned int lcore_id)
 	return ret;
 }
 
+static void mark_forked(void)
+{
+	is_forked++;
+}
+
 /* Launch threads, called at application init(). */
 int
 rte_eal_init(int argc, char **argv)
@@ -1324,6 +1331,8 @@ rte_eal_init(int argc, char **argv)
 
 	eal_mcfg_complete();
 
+	pthread_atfork(NULL, NULL, mark_forked);
+
 	return fctret;
 }
 
@@ -1347,6 +1356,9 @@ 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.
 	 */
@@ -1362,6 +1374,7 @@ rte_eal_cleanup(void)
 	vfio_mp_sync_cleanup();
 #endif
 	rte_mp_channel_cleanup();
+	rte_eal_intr_destroy();
 	rte_trace_save();
 	eal_trace_fini();
 	/* after this point, any DPDK pointers will become dangling */
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

Re: [PATCH v5] lib/eal: fix segfaults in exiting

[Stephen Hemminger]

On Tue,  6 Sep 2022 10:51:31 +0800
Zhichao Zeng <zhichaox.zeng@intel.com> wrote:

>  
> +static void mark_forked(void)
> +{
> +	is_forked++;
> +}
> +

This will end up counting application threads as well.

Also, it would need to be atomic.

>  /* Launch threads, called at application init(). */
>  int
>  rte_eal_init(int argc, char **argv)
> @@ -1324,6 +1331,8 @@ 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;
> +

rte_eal_cleanup is supposed to be called only once by application.

RE: [PATCH v5] lib/eal: fix segfaults in exiting

[Zeng, ZhichaoX]

Hi Stephen,

> >
> > +static void mark_forked(void)
> > +{
> > +	is_forked++;
> > +}
> > +
> 
> This will end up counting application threads as well.
> 

I think it would be counted in the child process when 'fork()' is called,
and in the parent process, it would be zero.

> Also, it would need to be atomic.
> 

Thanks for your advice.

> >  /* Launch threads, called at application init(). */  int
> > rte_eal_init(int argc, char **argv) @@ -1324,6 +1331,8 @@
> > 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;
> > +
> 
> rte_eal_cleanup is supposed to be called only once by application.

Yes. But in some case(e.g. debug_autotest of dpdk-test), it would fork
a child process to test 'rte_exit()', then it would call 'rte_eal_cleanup()'.
So 'is_forked' is introduced to avoid this situation.

Regards
Zhichao