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Date: Tue, 05 May 2015 02:16:39 +0100
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC: akpm@...ux-foundation.org, "Cong Wang" <xiyou.wangcong@...il.com>,
"Ignacy Gawędzki"
<ignacy.gawedzki@...en-communications.fr>,
"David S. Miller" <davem@...emloft.net>
Subject: [PATCH 3.2 192/221] gen_stats.c: Duplicate xstats buffer for
later use
3.2.69-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Ignacy Gawędzki <ignacy.gawedzki@...en-communications.fr>
[ Upstream commit 1c4cff0cf55011792125b6041bc4e9713e46240f ]
The gnet_stats_copy_app() function gets called, more often than not, with its
second argument a pointer to an automatic variable in the caller's stack.
Therefore, to avoid copying garbage afterwards when calling
gnet_stats_finish_copy(), this data is better copied to a dynamically allocated
memory that gets freed after use.
[xiyou.wangcong@...il.com: remove a useless kfree()]
Signed-off-by: Ignacy Gawędzki <ignacy.gawedzki@...en-communications.fr>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
net/core/gen_stats.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
--- a/net/core/gen_stats.c
+++ b/net/core/gen_stats.c
@@ -31,6 +31,9 @@ gnet_stats_copy(struct gnet_dump *d, int
return 0;
nla_put_failure:
+ kfree(d->xstats);
+ d->xstats = NULL;
+ d->xstats_len = 0;
spin_unlock_bh(d->lock);
return -1;
}
@@ -204,7 +207,9 @@ int
gnet_stats_copy_app(struct gnet_dump *d, void *st, int len)
{
if (d->compat_xstats) {
- d->xstats = st;
+ d->xstats = kmemdup(st, len, GFP_ATOMIC);
+ if (!d->xstats)
+ goto err_out;
d->xstats_len = len;
}
@@ -212,6 +217,11 @@ gnet_stats_copy_app(struct gnet_dump *d,
return gnet_stats_copy(d, TCA_STATS_APP, st, len);
return 0;
+
+err_out:
+ d->xstats_len = 0;
+ spin_unlock_bh(d->lock);
+ return -1;
}
EXPORT_SYMBOL(gnet_stats_copy_app);
@@ -244,6 +254,9 @@ gnet_stats_finish_copy(struct gnet_dump
return -1;
}
+ kfree(d->xstats);
+ d->xstats = NULL;
+ d->xstats_len = 0;
spin_unlock_bh(d->lock);
return 0;
}
--
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