Граф коммитов

155 Коммитов

Автор SHA1 Сообщение Дата
Pablo Neira Ayuso ae82ddcf8e rhashtable: fix lockdep splat in rhashtable_destroy()
No need for rht_dereference() from rhashtable_destroy() since the
existing callers don't hold the mutex when invoking this function
from:

1) Netlink, this is called in case of memory allocation errors in the
   initialization path, no nl_sk_hash_lock is held.
2) Netfilter, this is called from the rcu callback, no nfnl_lock is
   held either.

I think it's reasonable to assume that the caller has to make sure
that no hash resizing may happen before releasing the bucket array.
Therefore, the caller should be responsible for releasing this in a
safe way, document this to make people aware of it.

This resolves a rcu lockdep splat in nft_hash:

===============================
[ INFO: suspicious RCU usage. ]
3.16.0+ #178 Not tainted
-------------------------------
lib/rhashtable.c:596 suspicious rcu_dereference_protected() usage!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 1
1 lock held by ksoftirqd/2/18:
 #0:  (rcu_callback){......}, at: [<ffffffff810918fd>] rcu_process_callbacks+0x27e/0x4c7

stack backtrace:
CPU: 2 PID: 18 Comm: ksoftirqd/2 Not tainted 3.16.0+ #178
Hardware name: LENOVO 23259H1/23259H1, BIOS G2ET32WW (1.12 ) 05/30/2012
 0000000000000001 ffff88011706bb68 ffffffff8143debc 0000000000000000
 ffff880117062610 ffff88011706bb98 ffffffff81077515 ffff8800ca041a50
 0000000000000004 ffff8800ca386480 ffff8800ca041a00 ffff88011706bbb8
Call Trace:
 [<ffffffff8143debc>] dump_stack+0x4e/0x68
 [<ffffffff81077515>] lockdep_rcu_suspicious+0xfa/0x103
 [<ffffffff81228b1b>] rhashtable_destroy+0x46/0x52
 [<ffffffffa06f21a7>] nft_hash_destroy+0x73/0x82 [nft_hash]

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Thomas Graf <tgraf@suug.ch>
2014-09-03 10:57:12 +02:00
Geert Uytterhoeven 45d5acd3cd lib: rhashtable: Spelling s/compuate/compute/
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-08-26 09:35:56 +02:00
Thomas Graf c91eee56dc rhashtable: unexport and make rht_obj() static
No need to export rht_obj(), all inner to outer object translations
occur internally. It was intended to be used with rht_for_each() which
now primarily serves as the iterator for rhashtable_remove_pprev() to
effectively flush and free the full table.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-14 15:13:39 -07:00
Thomas Graf 5300fdcb7b rhashtable: RCU annotations for next pointers
Properly annotate next pointers as access is RCU protected in
the lookup path.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-14 15:13:39 -07:00
Thomas Graf 7e1e77636e lib: Resizable, Scalable, Concurrent Hash Table
Generic implementation of a resizable, scalable, concurrent hash table
based on [0]. The implementation supports both, fixed size keys specified
via an offset and length, or arbitrary keys via own hash and compare
functions.

Lookups are lockless and protected as RCU read side critical sections.
Automatic growing/shrinking based on user configurable watermarks is
available while allowing concurrent lookups to take place.

Objects to be hashed must include a struct rhash_head. The reason for not
using the existing struct hlist_head is that the expansion and shrinking
will have two buckets point to a single entry which would lead in obscure
reverse chaining behaviour.

Code includes a boot selftest if CONFIG_TEST_RHASHTABLE is defined.

[0] https://www.usenix.org/legacy/event/atc11/tech/final_files/Triplett.pdf

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Reviewed-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-02 19:49:38 -07:00