| From | Ben Hutchings <> | Date | Tue, 05 May 2015 02:16:39 +0100 | Subject | [PATCH 3.2 192/221] gen_stats.c: Duplicate xstats buffer for later use |
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3.2.69-rc1 review patch. If anyone has any objections, please let me know.
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From: Ignacy Gawędzki <ignacy.gawedzki@green-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@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> Signed-off-by: Ben Hutchings <ben@decadent.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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