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| author | Eric Dumazet <edumazet@google.com> | 2022-04-29 09:20:36 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-04-30 15:19:08 +0100 |
| commit | a9384a4c1d250cb40cebf50e41459426d160b08e (patch) | |
| tree | 26224d2aba035c4249666eeb6bd9317146976807 | |
| parent | dba5bdd57bea587ea4f0b79b03c71135f84a7e8b (diff) | |
| download | linux-a9384a4c1d250cb40cebf50e41459426d160b08e.tar.bz2 | |
mld: respect RCU rules in ip6_mc_source() and ip6_mc_msfilter()
Whenever RCU protected list replaces an object,
the pointer to the new object needs to be updated
_before_ the call to kfree_rcu() or call_rcu()
Also ip6_mc_msfilter() needs to update the pointer
before releasing the mc_lock mutex.
Note that linux-5.13 was supporting kfree_rcu(NULL, rcu),
so this fix does not need the conditional test I was
forced to use in the equivalent patch for IPv4.
Fixes: 882ba1f73c06 ("mld: convert ipv6_mc_socklist->sflist to RCU")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv6/mcast.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 909f937befd7..7f695c39d9a8 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -460,10 +460,10 @@ int ip6_mc_source(int add, int omode, struct sock *sk, newpsl->sl_addr[i] = psl->sl_addr[i]; atomic_sub(struct_size(psl, sl_addr, psl->sl_max), &sk->sk_omem_alloc); - kfree_rcu(psl, rcu); } + rcu_assign_pointer(pmc->sflist, newpsl); + kfree_rcu(psl, rcu); psl = newpsl; - rcu_assign_pointer(pmc->sflist, psl); } rv = 1; /* > 0 for insert logic below if sl_count is 0 */ for (i = 0; i < psl->sl_count; i++) { @@ -565,12 +565,12 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf, psl->sl_count, psl->sl_addr, 0); atomic_sub(struct_size(psl, sl_addr, psl->sl_max), &sk->sk_omem_alloc); - kfree_rcu(psl, rcu); } else { ip6_mc_del_src(idev, group, pmc->sfmode, 0, NULL, 0); } - mutex_unlock(&idev->mc_lock); rcu_assign_pointer(pmc->sflist, newpsl); + mutex_unlock(&idev->mc_lock); + kfree_rcu(psl, rcu); pmc->sfmode = gsf->gf_fmode; err = 0; done: |