[PATCH] examples/vdpa: fix devices cleanup

[PATCH] examples/vdpa: fix devices cleanup

[Yajun Wu]

Move rte_eal_cleanup to function vdpa_sample_quit which
handling all example app quit.
Otherwise rte_eal_cleanup won't be called on receiving signal
like SIGINT(control + c).

Fixes: 10aa3757 ("examples: add eal cleanup to examples")
Cc: stable@dpdk.org

Signed-off-by: Yajun Wu <yajunw@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
---
 examples/vdpa/main.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/examples/vdpa/main.c b/examples/vdpa/main.c
index 4c7e81d7b6..9149b66538 100644
--- a/examples/vdpa/main.c
+++ b/examples/vdpa/main.c
@@ -287,6 +287,8 @@ vdpa_sample_quit(void)
 		if (vports[i].ifname[0] != '\0')
 			close_vdpa(&vports[i]);
 	}
+	/* clean up the EAL */
+	rte_eal_cleanup();
 }
 
 static void
@@ -633,8 +635,5 @@ main(int argc, char *argv[])
 		vdpa_sample_quit();
 	}
 
-	/* clean up the EAL */
-	rte_eal_cleanup();
-
 	return 0;
 }
-- 
2.27.0

Re: [PATCH] examples/vdpa: fix devices cleanup

[Stephen Hemminger]

On Mon, 26 Dec 2022 14:51:06 +0800
Yajun Wu <yajunw@nvidia.com> wrote:

> Move rte_eal_cleanup to function vdpa_sample_quit which
> handling all example app quit.
> Otherwise rte_eal_cleanup won't be called on receiving signal
> like SIGINT(control + c).
> 
> Fixes: 10aa3757 ("examples: add eal cleanup to examples")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Yajun Wu <yajunw@nvidia.com>
> Acked-by: Matan Azrad <matan@nvidia.com>

NAK

rte_eal_cleanup is not signal safe.
This (and several other applications) are not managing termination
signals correctly. It is not safe to call many DPDK functions
from a signal handler. Imagine the case of getting SIGINT in
the middle of a driver holding a spin lock, then calling the
close function of that driver which then acquires the same lock.

The only safe way to handle signals is to set a flag
and do the shutdown and cleanup from the main loop.