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Subject[PATCH 4.14 027/165] netfilter: nft_set_hash: add rcu_barrier() in the nft_rhash_destroy()
Date
4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Taehee Yoo <ap420073@gmail.com>

[ Upstream commit 9970a8e40d4c39e23d62d32540366d1d7d2cce9b ]

GC of set uses call_rcu() to destroy elements.
So that elements would be destroyed after destroying sets and chains.
But, elements should be destroyed before destroying sets and chains.
In order to wait calling call_rcu(), a rcu_barrier() is added.

In order to test correctly, below patch should be applied.
https://patchwork.ozlabs.org/patch/940883/

test scripts:
%cat test.nft
table ip aa {
map map1 {
type ipv4_addr : verdict; flags timeout;
elements = {
0 : jump a0,
1 : jump a0,
2 : jump a0,
3 : jump a0,
4 : jump a0,
5 : jump a0,
6 : jump a0,
7 : jump a0,
8 : jump a0,
9 : jump a0,
}
timeout 1s;
}
chain a0 {
}
}
flush ruleset

[ ... ]

table ip aa {
map map1 {
type ipv4_addr : verdict; flags timeout;
elements = {
0 : jump a0,
1 : jump a0,
2 : jump a0,
3 : jump a0,
4 : jump a0,
5 : jump a0,
6 : jump a0,
7 : jump a0,
8 : jump a0,
9 : jump a0,
}
timeout 1s;
}
chain a0 {
}
}
flush ruleset

Splat looks like:
[ 200.795603] kernel BUG at net/netfilter/nf_tables_api.c:1363!
[ 200.806944] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[ 200.812253] CPU: 1 PID: 1582 Comm: nft Not tainted 4.17.0+ #24
[ 200.820297] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 07/08/2015
[ 200.830309] RIP: 0010:nf_tables_chain_destroy.isra.34+0x62/0x240 [nf_tables]
[ 200.838317] Code: 43 50 85 c0 74 26 48 8b 45 00 48 8b 4d 08 ba 54 05 00 00 48 c7 c6 60 6d 29 c0 48 c7 c7 c0 65 29 c0
4c 8b 40 08 e8 58 e5 fd f8 <0f> 0b 48 89 da 48 b8 00 00 00 00 00 fc ff
[ 200.860366] RSP: 0000:ffff880118dbf4d0 EFLAGS: 00010282
[ 200.866354] RAX: 0000000000000061 RBX: ffff88010cdeaf08 RCX: 0000000000000000
[ 200.874355] RDX: 0000000000000061 RSI: 0000000000000008 RDI: ffffed00231b7e90
[ 200.882361] RBP: ffff880118dbf4e8 R08: ffffed002373bcfb R09: ffffed002373bcfa
[ 200.890354] R10: 0000000000000000 R11: ffffed002373bcfb R12: dead000000000200
[ 200.898356] R13: dead000000000100 R14: ffffffffbb62af38 R15: dffffc0000000000
[ 200.906354] FS: 00007fefc31fd700(0000) GS:ffff88011b800000(0000) knlGS:0000000000000000
[ 200.915533] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 200.922355] CR2: 0000557f1c8e9128 CR3: 0000000106880000 CR4: 00000000001006e0
[ 200.930353] Call Trace:
[ 200.932351] ? nf_tables_commit+0x26f6/0x2c60 [nf_tables]
[ 200.939525] ? nf_tables_setelem_notify.constprop.49+0x1a0/0x1a0 [nf_tables]
[ 200.947525] ? nf_tables_delchain+0x6e0/0x6e0 [nf_tables]
[ 200.952383] ? nft_add_set_elem+0x1700/0x1700 [nf_tables]
[ 200.959532] ? nla_parse+0xab/0x230
[ 200.963529] ? nfnetlink_rcv_batch+0xd06/0x10d0 [nfnetlink]
[ 200.968384] ? nfnetlink_net_init+0x130/0x130 [nfnetlink]
[ 200.975525] ? debug_show_all_locks+0x290/0x290
[ 200.980363] ? debug_show_all_locks+0x290/0x290
[ 200.986356] ? sched_clock_cpu+0x132/0x170
[ 200.990352] ? find_held_lock+0x39/0x1b0
[ 200.994355] ? sched_clock_local+0x10d/0x130
[ 200.999531] ? memset+0x1f/0x40

Fixes: 9d0982927e79 ("netfilter: nft_hash: add support for timeouts")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/netfilter/nft_set_hash.c | 1 +
1 file changed, 1 insertion(+)

--- a/net/netfilter/nft_set_hash.c
+++ b/net/netfilter/nft_set_hash.c
@@ -359,6 +359,7 @@ static void nft_rhash_destroy(const stru
struct nft_rhash *priv = nft_set_priv(set);

cancel_delayed_work_sync(&priv->gc_work);
+ rcu_barrier();
rhashtable_free_and_destroy(&priv->ht, nft_rhash_elem_destroy,
(void *)set);
}

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