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Subject[PATCH 4.17 48/63] rhashtable: add restart routine in rhashtable_free_and_destroy()
Date
4.17-stable review patch.  If anyone has any objections, please let me know.

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

From: Taehee Yoo <ap420073@gmail.com>

[ Upstream commit 0026129c8629265bfe5079c1e017fa8543796d9f ]

rhashtable_free_and_destroy() cancels re-hash deferred work
then walks and destroys elements. at this moment, some elements can be
still in future_tbl. that elements are not destroyed.

test case:
nft_rhash_destroy() calls rhashtable_free_and_destroy() to destroy
all elements of sets before destroying sets and chains.
But rhashtable_free_and_destroy() doesn't destroy elements of future_tbl.
so that splat occurred.

test script:
%cat test.nft
table ip aa {
map map1 {
type ipv4_addr : verdict;
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,
}
}
chain a0 {
}
}
flush ruleset
table ip aa {
map map1 {
type ipv4_addr : verdict;
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,
}
}
chain a0 {
}
}
flush ruleset

%while :; do nft -f test.nft; done

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

V2:
- free all tables requested by Herbert Xu

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
lib/rhashtable.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -1107,13 +1107,14 @@ void rhashtable_free_and_destroy(struct
void (*free_fn)(void *ptr, void *arg),
void *arg)
{
- struct bucket_table *tbl;
+ struct bucket_table *tbl, *next_tbl;
unsigned int i;

cancel_work_sync(&ht->run_work);

mutex_lock(&ht->mutex);
tbl = rht_dereference(ht->tbl, ht);
+restart:
if (free_fn) {
for (i = 0; i < tbl->size; i++) {
struct rhash_head *pos, *next;
@@ -1130,7 +1131,12 @@ void rhashtable_free_and_destroy(struct
}
}

+ next_tbl = rht_dereference(tbl->future_tbl, ht);
bucket_table_free(tbl);
+ if (next_tbl) {
+ tbl = next_tbl;
+ goto restart;
+ }
mutex_unlock(&ht->mutex);
}
EXPORT_SYMBOL_GPL(rhashtable_free_and_destroy);

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