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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ido Schimmel <idosch@nvidia.com>,
        Adiel Bidani <adielb@nvidia.com>, Jiri Pirko <jiri@nvidia.com>,
        Petr Machata <petrm@nvidia.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.10 067/221] psample: Fix user API breakage
Date:   Mon, 29 Mar 2021 09:56:38 +0200
Message-Id: <20210329075631.414610879@linuxfoundation.org>
In-Reply-To: <20210329075629.172032742@linuxfoundation.org>
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From: Ido Schimmel <idosch@nvidia.com>

commit e43accba9b071dcd106b5e7643b1b106a158cbb1 upstream.

Cited commit added a new attribute before the existing group reference
count attribute, thereby changing its value and breaking existing
applications on new kernels.

Before:

 # psample -l
 libpsample ERROR psample_group_foreach: failed to recv message: Operation not supported

After:

 # psample -l
 Group Num       Refcount        Group Seq
 1               1               0

Fix by restoring the value of the old attribute and remove the
misleading comments from the enumerator to avoid future bugs.

Cc: stable@vger.kernel.org
Fixes: d8bed686ab96 ("net: psample: Add tunnel support")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reported-by: Adiel Bidani <adielb@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/uapi/linux/psample.h |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- a/include/uapi/linux/psample.h
+++ b/include/uapi/linux/psample.h
@@ -3,7 +3,6 @@
 #define __UAPI_PSAMPLE_H
 
 enum {
-	/* sampled packet metadata */
 	PSAMPLE_ATTR_IIFINDEX,
 	PSAMPLE_ATTR_OIFINDEX,
 	PSAMPLE_ATTR_ORIGSIZE,
@@ -11,10 +10,8 @@ enum {
 	PSAMPLE_ATTR_GROUP_SEQ,
 	PSAMPLE_ATTR_SAMPLE_RATE,
 	PSAMPLE_ATTR_DATA,
-	PSAMPLE_ATTR_TUNNEL,
-
-	/* commands attributes */
 	PSAMPLE_ATTR_GROUP_REFCOUNT,
+	PSAMPLE_ATTR_TUNNEL,
 
 	__PSAMPLE_ATTR_MAX
 };