RE: [DPDK] eal/linux: fix segfaults due to thread exit order

RE: [DPDK] eal/linux: fix segfaults due to thread exit order

[Morten Brørup]

> From: zhichaox.zeng@intel.com [mailto:zhichaox.zeng@intel.com]
> Sent: Tuesday, 17 May 2022 18.05
> 
> From: Zhichao Zeng <zhichaox.zeng@intel.com>
> 
> The eal-intr-thread is not closed before exiting the main
> thread. There is a small probability that when the
> eal-intr-thread is about to use some pointers, the pointers
> were just released in the process of exiting, which cause
> the segment fault error caught by ASan.
> 
> Close the eal-intr-thread before exiting the mian thread
> to avoid segment fault.
> 
> Signed-off-by: Zhichao Zeng <zhichaox.zeng@intel.com>
> ---

Acked-by: Morten Brørup <mb@smartsharesystems.com>

RE: [EXT] [DPDK] eal/linux: fix segfaults due to thread exit order

[Harman Kalra]

Hi Zhichao,

Can you please add the same API for freebsd also.

Thanks
Harman

> -----Original Message-----
> From: zhichaox.zeng@intel.com <zhichaox.zeng@intel.com>
> Sent: Tuesday, May 17, 2022 9:35 PM
> To: dev@dpdk.org; qiming.yang@intel.com
> Cc: Zhichao Zeng <zhichaox.zeng@intel.com>; Harman Kalra
> <hkalra@marvell.com>
> Subject: [EXT] [DPDK] eal/linux: fix segfaults due to thread exit order
> 
> External Email
> 
> ----------------------------------------------------------------------
> From: Zhichao Zeng <zhichaox.zeng@intel.com>
> 
> The eal-intr-thread is not closed before exiting the main thread. There is a
> small probability that when the eal-intr-thread is about to use some pointers,
> the pointers were just released in the process of exiting, which cause the
> segment fault error caught by ASan.
> 
> Close the eal-intr-thread before exiting the mian thread to avoid segment
> fault.
> 
> Signed-off-by: Zhichao Zeng <zhichaox.zeng@intel.com>
> ---
>  lib/eal/common/eal_private.h   |  7 +++++++
>  lib/eal/linux/eal.c            |  1 +
>  lib/eal/linux/eal_interrupts.c | 12 ++++++++++++
>  3 files changed, 20 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/linux/eal.c b/lib/eal/linux/eal.c index
> 1ef263434a..b310681acf 100644
> --- a/lib/eal/linux/eal.c
> +++ b/lib/eal/linux/eal.c
> @@ -1266,6 +1266,7 @@ 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..b246b87273 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 */
> +	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

[DPDK] eal/linux: fix segfaults due to thread exit order

[zhichaox.zeng]

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

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

Close the eal-intr-thread before exiting the mian thread
to avoid segment fault.

Signed-off-by: Zhichao Zeng <zhichaox.zeng@intel.com>
---
 lib/eal/common/eal_private.h   |  7 +++++++
 lib/eal/linux/eal.c            |  1 +
 lib/eal/linux/eal_interrupts.c | 12 ++++++++++++
 3 files changed, 20 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/linux/eal.c b/lib/eal/linux/eal.c
index 1ef263434a..b310681acf 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -1266,6 +1266,7 @@ 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..b246b87273 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 */
+	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

[DPDK v2] 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 exiting the main
thread. There is a small probability that when the
eal-intr-thread is about to use some pointers, the pointers
were just released in the process of exiting, which cause
the segment fault error caught by ASan.

Close the eal-intr-thread before exiting the mian thread
to avoid segment fault.

Signed-off-by: Zhichao Zeng <zhichaox.zeng@intel.com>
---
 lib/eal/common/eal_private.h     |  7 +++++++
 lib/eal/freebsd/eal.c            |  1 +
 lib/eal/freebsd/eal_interrupts.c | 11 +++++++++++
 lib/eal/linux/eal.c              |  1 +
 lib/eal/linux/eal_interrupts.c   | 12 ++++++++++++
 5 files changed, 32 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 a6b20960f2..0a6bd0efa3 100644
--- a/lib/eal/freebsd/eal.c
+++ b/lib/eal/freebsd/eal.c
@@ -893,6 +893,7 @@ rte_eal_cleanup(void)
 		eal_get_internal_configuration();
 	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..f9ea59720c 100644
--- a/lib/eal/freebsd/eal_interrupts.c
+++ b/lib/eal/freebsd/eal_interrupts.c
@@ -648,6 +648,17 @@ rte_eal_intr_init(void)
 	return ret;
 }
 
+void
+rte_eal_intr_destroy()
+{
+	/* cancel the host thread */
+	pthread_cancel(intr_thread);
+	pthread_join(intr_thread, NULL);
+
+	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..b310681acf 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -1266,6 +1266,7 @@ 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..b246b87273 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 */
+	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 v2] 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.

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

---
v2: add the same API for FreeBSD
---
 lib/eal/common/eal_private.h     |  7 +++++++
 lib/eal/freebsd/eal.c            |  1 +
 lib/eal/freebsd/eal_interrupts.c | 12 ++++++++++++
 lib/eal/linux/eal.c              |  1 +
 lib/eal/linux/eal_interrupts.c   | 12 ++++++++++++
 5 files changed, 33 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 a6b20960f2..0a6bd0efa3 100644
--- a/lib/eal/freebsd/eal.c
+++ b/lib/eal/freebsd/eal.c
@@ -893,6 +893,7 @@ rte_eal_cleanup(void)
 		eal_get_internal_configuration();
 	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..b310681acf 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -1266,6 +1266,7 @@ 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

Re: [PATCH v2] lib/eal: fix segfaults due to thread exit order

[David Marchand]

On Mon, May 23, 2022 at 5:17 AM <zhichaox.zeng@intel.com> wrote:
>
> 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.

This breaks the debug_autotest unit test.
It results in a segfault in a forked process executing
rte_exit()/rte_eal_cleanup().

That's probably because intr_thread thread does not exist in the forked process.


-- 
David Marchand

Re: [PATCH v2] lib/eal: fix segfaults due to thread exit order

[David Marchand]

On Mon, May 23, 2022 at 2:10 PM David Marchand
<david.marchand@redhat.com> wrote:
>
> On Mon, May 23, 2022 at 5:17 AM <zhichaox.zeng@intel.com> wrote:
> >
> > 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.
>
> This breaks the debug_autotest unit test.
> It results in a segfault in a forked process executing
> rte_exit()/rte_eal_cleanup().
>
> That's probably because intr_thread thread does not exist in the forked process.

Reading fork() manual:
       *  The  child  process is created with a single thread—the one
that called fork().  The entire virtual address space of the parent is
replicated in the child, including the states of mutexes, condi‐
          tion variables, and other pthreads objects; the use of
pthread_atfork(3) may be helpful for dealing with problems that this
can cause.


We may need a check like diff below.
But then, debug_autotest code seems dangerous, because it does exactly
what the added check wants to warn about.

Opinions?


diff --git a/lib/eal/linux/eal.c b/lib/eal/linux/eal.c
index 1ef263434a..1e6fd01d5d 100644
--- a/lib/eal/linux/eal.c
+++ b/lib/eal/linux/eal.c
@@ -857,12 +857,25 @@ is_iommu_enabled(void)
        return n > 2;
 }

+static uint32_t run_once;
+
+static void warn_parent(void)
+{
+       RTE_LOG(WARNING, EAL, "fork() was called, DPDK won't work in the child "
+               "process unless it calls rte_eal_init()\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 +1241,8 @@ rte_eal_init(int argc, char **argv)

        eal_mcfg_complete();

+       pthread_atfork(NULL, warn_parent, scratch_child);
+
        return fctret;
 }

@@ -1257,6 +1272,9 @@ 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);


-- 
David Marchand

[PATCH v3] 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.

---
v2: add the same API for FreeBSD
---
v3: fix rte_eal_cleanup crash in debug_autotest

Signed-off-by: Zhichao Zeng <zhichaox.zeng@intel.com>
---
 lib/eal/common/eal_private.h     |  7 +++++++
 lib/eal/freebsd/eal.c            | 22 +++++++++++++++++++++-
 lib/eal/freebsd/eal_interrupts.c | 12 ++++++++++++
 lib/eal/linux/eal.c              | 21 ++++++++++++++++++++-
 lib/eal/linux/eal_interrupts.c   | 12 ++++++++++++
 5 files changed, 72 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..6875a9f6d2 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 +576,23 @@ 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, "fork() was called, DPDK won't work in the child "
+		"process unless it calls rte_eal_init()\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 +896,8 @@ rte_eal_init(int argc, char **argv)
 
 	eal_mcfg_complete();
 
+	pthread_atfork(NULL, warn_parent, scratch_child);
+
 	return fctret;
 }
 
@@ -891,8 +906,13 @@ 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..32c7adaa52 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 +859,23 @@ is_iommu_enabled(void)
 	return n > 2;
 }
 
+static void warn_parent(void)
+{
+	RTE_LOG(WARNING, EAL, "fork() was called, DPDK won't work in the child "
+		"process unless it calls rte_eal_init()\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 +1241,8 @@ rte_eal_init(int argc, char **argv)
 
 	eal_mcfg_complete();
 
+	pthread_atfork(NULL, warn_parent, scratch_child);
+
 	return fctret;
 }
 
@@ -1257,6 +1272,9 @@ 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 +1284,7 @@ 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

Re: [PATCH v3] lib/eal: fix segfaults due to thread exit order

[Stephen Hemminger]

On Mon, 30 May 2022 13:47:38 +0000
zhichaox.zeng@intel.com wrote:

> +static void warn_parent(void)
> +{
> +	RTE_LOG(WARNING, EAL, "fork() was called, DPDK won't work in the child "
> +		"process unless it calls rte_eal_init()\n");
> +}
> +

Too wordy. Don't break messages across lines.

Re: [PATCH v3] lib/eal: fix segfaults due to thread exit order

[Stephen Hemminger]

On Mon, 30 May 2022 13:47:38 +0000
zhichaox.zeng@intel.com wrote:

> @@ -883,6 +896,8 @@ rte_eal_init(int argc, char **argv)
>  
>  	eal_mcfg_complete();
>  
> +	pthread_atfork(NULL, warn_parent, scratch_child);
> +
>  	return fctret;
>  }

There are lots of other cases where DPDK will die if you fork()
in a DPDK process then call DPDK functions in child. 

Not sure what the problem you are trying to solve is?

RE: [PATCH v3] lib/eal: fix segfaults due to thread exit order

[Zeng, ZhichaoX]

Hi Stephen:

> -----Original Message-----
> From: Stephen Hemminger <stephen@networkplumber.org> 
> Sent: Tuesday, May 31, 2022 12:29 AM
> To: Zeng, ZhichaoX <zhichaox.zeng@intel.com>
> Cc: dev@dpdk.org; Yang, Qiming <qiming.yang@intel.com>; Richardson, Bruce <bruce.richardson@intel.com>; hkalra@marvell.com; david.marchand@redhat.com; aconole@redhat.com; Matz, Olivier > > <olivier.matz@6wind.com>; thomas@monjalon.net; stable@dpdk.org
> Subject: Re: [PATCH v3] lib/eal: fix segfaults due to thread exit order
>
> On Mon, 30 May 2022 13:47:38 +0000
> zhichaox.zeng@intel.com wrote:

> > @@ -883,6 +896,8 @@ rte_eal_init(int argc, char **argv)
> >  
> >  	eal_mcfg_complete();
> >  
> > +	pthread_atfork(NULL, warn_parent, scratch_child);
> > +
> >  	return fctret;
> >  }

> There are lots of other cases where DPDK will die if you fork() in a DPDK process then call DPDK functions in child. 

> Not sure what the problem you are trying to solve is?

The original goal of this patch was to cancel eal-intr-thread before memory cleanup to avoid a small probability of segfaults. 

But in the debug_autotest test of dpdk-test, fork() is called and the exit process is tested in the child process which will call the rte_eal_cleanup function and mistakenly clean up non-existing threads. This will cause segmentation fault. 

Based on patch v2, atomic operation is added to determine whether it is a child process, so that the cleaning process will not execute in the child process to avoid the above problem.

Regards

RE: [PATCH v3] lib/eal: fix segfaults due to thread exit order

[Zeng, ZhichaoX]

Hi David, Harman

Please review this patch at your convenience. Thanks!

In addition, I tried to figure out the reason for the failure of the CI test. There is a saying that
this is a problem with Asan when cancelling a thread that is waiting on epoll. After adding the 
'-fstack-protector-all' parameter, there will be no exception. But I don't know the software 
environment for automated testing, so I can't verify this statement.

Regards

> Subject: [PATCH v3] lib/eal: fix segfaults due to thread exit order

> 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.

> ---
> v2: add the same API for FreeBSD
> ---
> v3: fix rte_eal_cleanup crash in debug_autotest

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

[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

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

[Zeng, ZhichaoX]

Hi David, Harman
    Please review this patch at your convenience, it's been about a month since the v1 version.
    Thanks!

Best regards
Zhichao

> -----Original Message-----
> From: Zeng, ZhichaoX <zhichaox.zeng@intel.com> 
> Sent: Wednesday, June 15, 2022 2:02 PM
> To: dev@dpdk.org
> Cc: stable@dpdk.org; Yang, Qiming <qiming.yang@intel.com>; david.marchand@redhat.com; stephen@networkplumber.org; mb@smartsharesystems.com; Zeng, ZhichaoX <zhichaox.zeng@intel.com>; Richardson, Bruce > <bruce.richardson@intel.com>; Harman Kalra <hkalra@marvell.com>
> Subject: [PATCH v4] lib/eal: fix segfaults due to thread exit order
>
> 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>

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

[David Marchand]

On Fri, Jun 24, 2022 at 3:42 AM Zeng, ZhichaoX <zhichaox.zeng@intel.com> wrote:
>
> Hi David, Harman
>     Please review this patch at your convenience, it's been about a month since the v1 version.
>     Thanks!

Yes, it's been a month.
Feel free to help on reviewing patches from others so that reviews can
be quicker for everyone.

Thanks.

-- 
David Marchand

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

[Zeng, ZhichaoX]

Hi Harman, Bruce
    Could you please help to review this patch, thank you so much!

Best regards
Zhichao

> -----Original Message-----
> From: Zeng, ZhichaoX <zhichaox.zeng@intel.com> 
> Sent: Wednesday, June 15, 2022 2:02 PM
> To: dev@dpdk.org
> Cc: stable@dpdk.org; Yang, Qiming <qiming.yang@intel.com>; david.marchand@redhat.com; stephen@networkplumber.org; mb@smartsharesystems.com; Zeng, ZhichaoX <zhichaox.zeng@intel.com>; Richardson, Bruce > <bruce.richardson@intel.com>; Harman Kalra <hkalra@marvell.com>
> Subject: [PATCH v4] lib/eal: fix segfaults due to thread exit order
>
> 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>

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

[Bruce Richardson]

On Wed, Jun 15, 2022 at 02:01:54PM +0800, zhichaox.zeng@intel.com wrote:
> 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
> 

Hi,

some comments inline below.

/Bruce

> ---
> 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
> 

Please put these updates below the cutline after the sign-offs, i.e.
immediately before the diffstat.

> 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;
>  

I don't like just moving this variable from the eal_init function. When in
eal_init the name "run_once" made sense as it tracked how often the EAL
init function was run. However, now as a global variable the name
"run_once" no longer makes sense.

Two suggestions:
1. Keep run_once in EAL init as-is, and use a different variable or value
   to indicate that DPDK is initialized for cleanup.
2. Move the variable as you have here, just rename it to a more meaningful
   name.


>  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");
> +}

I wonder if this contains enough information. Can we identify briefly what
parts will or won't work, or if we just want to deny everything, can we
give a brief reason why?

> +
> +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);
> +}
> +

I think the name of this function needs improvement. I'm not sure that
"scratch" is the best term to use. Something like "clear_eal_flag" is
probably better.

>  /* 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();
<snip for brevity>

[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

[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@dpdk.org

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

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

[Stephen Hemminger]

On Tue, 11 Oct 2022 13:25:14 +0800
Zhichao Zeng <zhichaox.zeng@intel.com> wrote:

> 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

This is a test bug, not an DPDK bug. I don't think DPDK should account
for misuse of API in this way.

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

[Zeng, ZhichaoX]

Hi Stephen, thanks for your comments. 

The original goal of this patch is to close the 'eal-intr-thread' to fix segfaults
caught by Asan. But it breaks the debug_autotest unit test.

So the flag is added to fix the unit test.

Hi @David Marchand, what's your suggestions?

BR
Zhichao

> -----Original Message-----
> From: Stephen Hemminger <stephen@networkplumber.org>
> Sent: Tuesday, October 11, 2022 10:04 PM
> To: Zeng, ZhichaoX <zhichaox.zeng@intel.com>
> Cc: dev@dpdk.org; stable@dpdk.org; Zhou, YidingX
> <yidingx.zhou@intel.com>; Richardson, Bruce
> <bruce.richardson@intel.com>; Harman Kalra <hkalra@marvell.com>
> Subject: Re: [PATCH v6] lib/eal: fix segfaults in exiting
> 
> On Tue, 11 Oct 2022 13:25:14 +0800
> Zhichao Zeng <zhichaox.zeng@intel.com> wrote:
> 
> > 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
> 
> This is a test bug, not an DPDK bug. I don't think DPDK should account for
> misuse of API in this way.