From: Ignacy Gawędzki Date: Fri, 13 Feb 2015 22:47:05 +0000 (-0800) Subject: gen_stats.c: Duplicate xstats buffer for later use X-Git-Tag: v3.2.69~30 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=24aa85b0d9ef3f2cd3d99be59bbf58fba269ba08 gen_stats.c: Duplicate xstats buffer for later use [ 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 Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c index 0452eb27a272..91080c190c33 100644 --- a/net/core/gen_stats.c +++ b/net/core/gen_stats.c @@ -31,6 +31,9 @@ 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; } @@ -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, 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); @@ -244,6 +254,9 @@ 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; }