Re: [slab poison overwritten] Re: [GIT] Networking

Le lundi 21 mars 2011 à 19:07 +0100, Eric Dumazet a écrit :

Le lundi 21 mars 2011 à 18:39 +0100, Ingo Molnar a écrit :

quoted

here's the same but with kallsyms enabled.

Thanks,

	Ingo

[    9.585627] initcall 0xffffffff81d5b806 returned 0 after 0 usecs
[    9.588960] calling  0xffffffff81d5b9da @ 1
[    9.592303] IPVS: Creating netns size=1272 id=0
[    9.595646] IPVS: __ip_vs_control_init(): alloc_percpu.
[    9.602298] IPVS: cannot register namespace.
[    9.605627] IPVS: can't setup control

It seems IPVS is busted in case of memory allocation error in 
__ip_vs_control_init()

IPVS deinits its "struct netns_ipvs" space, but something (in IPVS) uses
it after free.

__ip_vs_init() seems to be called before ip_vs_init() completes
correctly. We then keep in net->ipvs a pointer to some freed memory.

Commit 14e405461e664b7 did some changes in this area

Simon, any idea ?

For the time being, we can avoid the false memory allocation error (and
leak)

Thanks

[PATCH] ipvs: fix a typo in __ip_vs_control_init()

Reported-by: Ingo Molnar <redacted>
Signed-off-by: Eric Dumazet <redacted>
Cc: Simon Horman <horms@verge.net.au>
Cc: Julian Anastasov <ja@ssi.bg>
---
 net/netfilter/ipvs/ip_vs_ctl.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index b799cea..33733c8 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c

@@ -3605,7 +3605,7 @@ int __net_init __ip_vs_control_init(struct net *net)
 
 	/* procfs stats */
 	ipvs->tot_stats.cpustats = alloc_percpu(struct ip_vs_cpu_stats);
-	if (ipvs->tot_stats.cpustats) {
+	if (!ipvs->tot_stats.cpustats) {
 		pr_err("%s(): alloc_percpu.\n", __func__);
 		return -ENOMEM;
 	}