4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Davide Caratti dcaratti@redhat.com
[ Upstream commit f29cdfbe33d6915ba8056179b0041279a67e3647 ]
tcf_skbmod_init() can fail after the idr has been successfully reserved. When this happens, every subsequent attempt to configure skbmod rules using the same idr value will systematically fail with -ENOSPC, unless the first attempt was done using the 'replace' keyword:
# tc action add action skbmod swap mac index 100 RTNETLINK answers: Cannot allocate memory We have an error talking to the kernel # tc action add action skbmod swap mac index 100 RTNETLINK answers: No space left on device We have an error talking to the kernel # tc action add action skbmod swap mac index 100 RTNETLINK answers: No space left on device We have an error talking to the kernel ...
Fix this in tcf_skbmod_init(), ensuring that tcf_idr_release() is called on the error path when the idr has been reserved, but not yet inserted. Also, don't test 'ovr' in the error path, to avoid a 'replace' failure implicitly become a 'delete' that leaks refcount in act_skbmod module:
# rmmod act_skbmod; modprobe act_skbmod # tc action add action skbmod swap mac index 100 # tc action add action skbmod swap mac continue index 100 RTNETLINK answers: File exists We have an error talking to the kernel # tc action replace action skbmod swap mac continue index 100 RTNETLINK answers: Cannot allocate memory We have an error talking to the kernel # tc action list action skbmod # # rmmod act_skbmod rmmod: ERROR: Module act_skbmod is in use
Fixes: 65a206c01e8e ("net/sched: Change act_api and act_xxx modules to use IDR") Acked-by: Jamal Hadi Salim jhs@mojatatu.com Signed-off-by: Davide Caratti dcaratti@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/act_skbmod.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/sched/act_skbmod.c +++ b/net/sched/act_skbmod.c @@ -155,7 +155,7 @@ static int tcf_skbmod_init(struct net *n ASSERT_RTNL(); p = kzalloc(sizeof(struct tcf_skbmod_params), GFP_KERNEL); if (unlikely(!p)) { - if (ovr) + if (ret == ACT_P_CREATED) tcf_idr_release(*a, bind); return -ENOMEM; }