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| author | Cong Wang <xiyou.wangcong@gmail.com> | 2018-08-19 12:22:13 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-08-21 12:45:45 -0700 |
| commit | 5ffe57da29b3802baeddaa40909682bbb4cb4d48 (patch) | |
| tree | 445afddd040006b43d6d2ad85118b558ded5ca6c /net/sched/act_ife.c | |
| parent | 4e407ff5cd67ec76eeeea1deec227b7982dc7f66 (diff) | |
| download | linux-5ffe57da29b3802baeddaa40909682bbb4cb4d48.tar.gz | |
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: 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>
Diffstat (limited to 'net/sched/act_ife.c')
| -rw-r--r-- | net/sched/act_ife.c | 34 |
1 files changed, 21 insertions, 13 deletions
diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c index 244a8cf48183..196430aefe87 100644 --- a/net/sched/act_ife.c +++ b/net/sched/act_ife.c @@ -296,22 +296,16 @@ static int load_metaops_and_vet(u32 metaid, void *val, int len, bool rtnl_held) /* 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; @@ -319,7 +313,6 @@ static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval, ret = ops->alloc(mi, metaval, atomic ? GFP_ATOMIC : GFP_KERNEL); if (ret != 0) { kfree(mi); - module_put(ops->owner); return ret; } } @@ -333,6 +326,21 @@ static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval, 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; @@ -341,7 +349,7 @@ static int use_all_metadata(struct tcf_ife_info *ife, bool exists) 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; } @@ -435,7 +443,7 @@ static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb, 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; } |