diff options
| author |   Florian Westphal <fw@strlen.de> | 2021-03-25 18:25:12 +0100 |
|---|---|---|
| committer |   Pablo Neira Ayuso <pablo@netfilter.org> | 2021-03-31 22:34:11 +0200 |
| commit | cefa31a9d46112c0706c218ea549bccf298a0068 (patch) | |
| tree | 8a9fdcb23a6d93fd5c10305e525dcb7ed1e964e9 /include/net/netfilter | |
| parent | netfilter: nf_log: add module softdeps (diff) | |
| download | linux-dev-cefa31a9d46112c0706c218ea549bccf298a0068.tar.xz linux-dev-cefa31a9d46112c0706c218ea549bccf298a0068.zip | |
netfilter: nft_log: perform module load from nf_tables
modprobe calls from the nf_logger_find_get() API causes deadlock in very
special cases because they occur with the nf_tables transaction mutex held.
In the specific case of nf_log, deadlock is via:
A nf_tables -> transaction mutex -> nft_log -> modprobe -> nf_log_syslog \
-> pernet_ops rwsem -> wait for C
B netlink event -> rtnl_mutex -> nf_tables transaction mutex -> wait for A
C close() -> ip6mr_sk_done -> rtnl_mutex -> wait for B
Earlier patch added NFLOG/xt_LOG module softdeps to avoid the need to load
the backend module during a transaction.
For nft_log we would have to add a softdep for both nfnetlink_log or
nf_log_syslog, since we do not know in advance which of the two backends
are going to be configured.
This defers the modprobe op until after the transaction mutex is released.
Tested-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'include/net/netfilter')
| -rw-r--r-- | include/net/netfilter/nf_tables.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 0cef5ad9768a..8fefa112ae89 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -1562,4 +1562,9 @@ void nf_tables_trans_destroy_flush_work(void); int nf_msecs_to_jiffies64(const struct nlattr *nla, u64 *result); __be64 nf_jiffies64_to_msecs(u64 input); +#ifdef CONFIG_MODULES +__printf(2, 3) int nft_request_module(struct net *net, const char *fmt, ...); +#else +static inline int nft_request_module(struct net *net, const char *fmt, ...) { return -ENOENT; } +#endif #endif /* _NET_NF_TABLES_H */ |