act_ife: fix a potential deadlock
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: 817e9f2c5c
("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>
This commit is contained in:
parent
4e407ff5cd
commit
5ffe57da29
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@ -296,22 +296,16 @@ static int load_metaops_and_vet(u32 metaid, void *val, int len, bool rtnl_held)
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/* called when adding new meta information
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*/
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static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,
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static int __add_metainfo(const struct tcf_meta_ops *ops,
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struct tcf_ife_info *ife, u32 metaid, void *metaval,
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int len, bool atomic, bool exists)
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{
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struct tcf_meta_info *mi = NULL;
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struct tcf_meta_ops *ops = find_ife_oplist(metaid);
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int ret = 0;
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if (!ops)
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return -ENOENT;
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mi = kzalloc(sizeof(*mi), atomic ? GFP_ATOMIC : GFP_KERNEL);
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if (!mi) {
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/*put back what find_ife_oplist took */
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module_put(ops->owner);
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if (!mi)
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return -ENOMEM;
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}
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mi->metaid = metaid;
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mi->ops = ops;
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@ -319,7 +313,6 @@ static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,
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ret = ops->alloc(mi, metaval, atomic ? GFP_ATOMIC : GFP_KERNEL);
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if (ret != 0) {
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kfree(mi);
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module_put(ops->owner);
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return ret;
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}
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}
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@ -333,6 +326,21 @@ static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,
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return ret;
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}
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static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,
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int len, bool exists)
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{
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const struct tcf_meta_ops *ops = find_ife_oplist(metaid);
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int ret;
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if (!ops)
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return -ENOENT;
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ret = __add_metainfo(ops, ife, metaid, metaval, len, false, exists);
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if (ret)
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/*put back what find_ife_oplist took */
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module_put(ops->owner);
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return ret;
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}
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static int use_all_metadata(struct tcf_ife_info *ife, bool exists)
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{
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struct tcf_meta_ops *o;
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@ -341,7 +349,7 @@ static int use_all_metadata(struct tcf_ife_info *ife, bool exists)
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read_lock(&ife_mod_lock);
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list_for_each_entry(o, &ifeoplist, list) {
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rc = add_metainfo(ife, o->metaid, NULL, 0, true, exists);
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rc = __add_metainfo(o, ife, o->metaid, NULL, 0, true, exists);
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if (rc == 0)
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installed += 1;
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}
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@ -435,7 +443,7 @@ static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb,
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if (rc != 0)
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return rc;
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rc = add_metainfo(ife, i, val, len, false, exists);
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rc = add_metainfo(ife, i, val, len, exists);
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if (rc)
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return rc;
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}
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