[dpdk-stable] patch 'net/tap: fix unexpected link handler' has been queued to stable release 19.11.3

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 19.11.3

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/21/20. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Thanks.

Luca Boccassi

---
>From d28299df0a2419b69b35ad5b3d2205ad6605a8a6 Mon Sep 17 00:00:00 2001
From: Yunjian Wang <wangyunjian at huawei.com>
Date: Thu, 16 Apr 2020 21:50:52 +0800
Subject: [PATCH] net/tap: fix unexpected link handler

[ upstream commit dc1a4d86c63732e57e9593919504e8c81f46fcdf ]

The nic's interrupt source has some active handler, which maybe call
tap_dev_intr_handler() to set link handler. We should cancel the link
handler before close fd to prevent executing the link handler. It
triggers segfault.

Call Trace:
   0x00007f15e08dad99 in __rte_panic (Error adding fd %d epoll_ctl, %s\n")
   0x00007f15e08e9b87 in eal_intr_thread_main ()
   0x00007f15e249be15 in start_thread ()
   0x00007f15d5322f9d in clone ()

Fixes: c0bddd3a057f ("net/tap: add link status notification")

Signed-off-by: Yunjian Wang <wangyunjian at huawei.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit at intel.com>
---
 drivers/net/tap/rte_eth_tap.c | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index fea464c3d2..e644f8875b 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -18,6 +18,7 @@
 #include <rte_string_fns.h>
 #include <rte_ethdev.h>
 #include <rte_errno.h>
+#include <rte_cycles.h>
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -1599,13 +1600,12 @@ static int
 tap_lsc_intr_handle_set(struct rte_eth_dev *dev, int set)
 {
 	struct pmd_internals *pmd = dev->data->dev_private;
+	int ret;
 
 	/* In any case, disable interrupt if the conf is no longer there. */
 	if (!dev->data->dev_conf.intr_conf.lsc) {
 		if (pmd->intr_handle.fd != -1) {
-			tap_nl_final(pmd->intr_handle.fd);
-			rte_intr_callback_unregister(&pmd->intr_handle,
-				tap_dev_intr_handler, dev);
+			goto clean;
 		}
 		return 0;
 	}
@@ -1616,9 +1616,26 @@ tap_lsc_intr_handle_set(struct rte_eth_dev *dev, int set)
 		return rte_intr_callback_register(
 			&pmd->intr_handle, tap_dev_intr_handler, dev);
 	}
+
+clean:
+	do {
+		ret = rte_intr_callback_unregister(&pmd->intr_handle,
+			tap_dev_intr_handler, dev);
+		if (ret >= 0) {
+			break;
+		} else if (ret == -EAGAIN) {
+			rte_delay_ms(100);
+		} else {
+			TAP_LOG(ERR, "intr callback unregister failed: %d",
+				     ret);
+			break;
+		}
+	} while (true);
+
 	tap_nl_final(pmd->intr_handle.fd);
-	return rte_intr_callback_unregister(&pmd->intr_handle,
-					    tap_dev_intr_handler, dev);
+	pmd->intr_handle.fd = -1;
+
+	return 0;
 }
 
 static int
-- 
2.20.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2020-05-19 14:04:48.459531234 +0100
+++ 0098-net-tap-fix-unexpected-link-handler.patch	2020-05-19 14:04:44.308650040 +0100
@@ -1,8 +1,10 @@
-From dc1a4d86c63732e57e9593919504e8c81f46fcdf Mon Sep 17 00:00:00 2001
+From d28299df0a2419b69b35ad5b3d2205ad6605a8a6 Mon Sep 17 00:00:00 2001
 From: Yunjian Wang <wangyunjian at huawei.com>
 Date: Thu, 16 Apr 2020 21:50:52 +0800
 Subject: [PATCH] net/tap: fix unexpected link handler
 
+[ upstream commit dc1a4d86c63732e57e9593919504e8c81f46fcdf ]
+
 The nic's interrupt source has some active handler, which maybe call
 tap_dev_intr_handler() to set link handler. We should cancel the link
 handler before close fd to prevent executing the link handler. It
@@ -15,7 +17,6 @@
    0x00007f15d5322f9d in clone ()
 
 Fixes: c0bddd3a057f ("net/tap: add link status notification")
-Cc: stable at dpdk.org
 
 Signed-off-by: Yunjian Wang <wangyunjian at huawei.com>
 Reviewed-by: Ferruh Yigit <ferruh.yigit at intel.com>