4.18-stable review patch. If anyone has any objections, please let me know.
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From: Cong Wang xiyou.wangcong@gmail.com
[ Upstream commit 5ffe57da29b3802baeddaa40909682bbb4cb4d48 ]
use_all_metadata() acquires read_lock(&ife_mod_lock), then calls add_metainfo() which calls find_ife_oplist() which acquires the same lock again. Deadlock!
Introduce __add_metainfo() which accepts struct tcf_meta_ops *ops as an additional parameter and let its callers to decide how to find it. For use_all_metadata(), it already has ops, no need to find it again, just call __add_metainfo() directly.
And, as ife_mod_lock is only needed for find_ife_oplist(), this means we can make non-atomic allocation for populate_metalist() now.
Fixes: 817e9f2c5c26 ("act_ife: acquire ife_mod_lock before reading ifeoplist") Cc: Jamal Hadi Salim jhs@mojatatu.com Signed-off-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/act_ife.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-)
--- a/net/sched/act_ife.c +++ b/net/sched/act_ife.c @@ -294,22 +294,16 @@ static int load_metaops_and_vet(u32 meta
/* called when adding new meta information */ -static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval, - int len, bool atomic, bool exists) +static int __add_metainfo(const struct tcf_meta_ops *ops, + struct tcf_ife_info *ife, u32 metaid, void *metaval, + int len, bool atomic, bool exists) { struct tcf_meta_info *mi = NULL; - struct tcf_meta_ops *ops = find_ife_oplist(metaid); int ret = 0;
- if (!ops) - return -ENOENT; - mi = kzalloc(sizeof(*mi), atomic ? GFP_ATOMIC : GFP_KERNEL); - if (!mi) { - /*put back what find_ife_oplist took */ - module_put(ops->owner); + if (!mi) return -ENOMEM; - }
mi->metaid = metaid; mi->ops = ops; @@ -317,7 +311,6 @@ static int add_metainfo(struct tcf_ife_i ret = ops->alloc(mi, metaval, atomic ? GFP_ATOMIC : GFP_KERNEL); if (ret != 0) { kfree(mi); - module_put(ops->owner); return ret; } } @@ -331,6 +324,21 @@ static int add_metainfo(struct tcf_ife_i return ret; }
+static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval, + int len, bool exists) +{ + const struct tcf_meta_ops *ops = find_ife_oplist(metaid); + int ret; + + if (!ops) + return -ENOENT; + ret = __add_metainfo(ops, ife, metaid, metaval, len, false, exists); + if (ret) + /*put back what find_ife_oplist took */ + module_put(ops->owner); + return ret; +} + static int use_all_metadata(struct tcf_ife_info *ife, bool exists) { struct tcf_meta_ops *o; @@ -339,7 +347,7 @@ static int use_all_metadata(struct tcf_i
read_lock(&ife_mod_lock); list_for_each_entry(o, &ifeoplist, list) { - rc = add_metainfo(ife, o->metaid, NULL, 0, true, exists); + rc = __add_metainfo(o, ife, o->metaid, NULL, 0, true, exists); if (rc == 0) installed += 1; } @@ -433,7 +441,7 @@ static int populate_metalist(struct tcf_ if (rc != 0) return rc;
- rc = add_metainfo(ife, i, val, len, false, exists); + rc = add_metainfo(ife, i, val, len, exists); if (rc) return rc; }