gen_stats.c: Duplicate xstats buffer for later use (1c4cff0c) · Commits · 戴 / test

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@gmail.com: remove a useless kfree()] Signed-off-by:

Ignacy Gawędzki <ignacy.gawedzki@green-communications.fr> Signed-off-by:

Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/core/gen_stats.c

+14 −1

Original line number	Diff line number	Diff line
		@@ -32,6 +32,9 @@ gnet_stats_copy(struct gnet_dump d, int type, void buf, int size)
		return 0;

		nla_put_failure:
		kfree(d->xstats);
		d->xstats = NULL;
		d->xstats_len = 0;
		spin_unlock_bh(d->lock);
		return -1;
		}
		@@ -305,7 +308,9 @@ 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;
		}

		@@ -313,6 +318,11 @@ gnet_stats_copy_app(struct gnet_dump d, void st, int len)
		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);

		@@ -345,6 +355,9 @@ gnet_stats_finish_copy(struct gnet_dump *d)
		return -1;
		}

		kfree(d->xstats);
		d->xstats = NULL;
		d->xstats_len = 0;
		spin_unlock_bh(d->lock);
		return 0;
		}

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