Commit Graph

156 Commits

Author SHA1 Message Date
NeilBrown 82208d0d54 rhashtable: detect when object movement between tables might have invalidated a lookup
Some users of rhashtables might need to move an object from one table
to another -  this appears to be the reason for the incomplete usage
of NULLS markers.

To support these, we store a unique NULLS_MARKER at the end of
each chain, and when a search fails to find a match, we check
if the NULLS marker found was the expected one.  If not, the search
may not have examined all objects in the target bucket, so it is
repeated.

The unique NULLS_MARKER is derived from the address of the
head of the chain.  As this cannot be derived at load-time the
static rhnull in rht_bucket_nested() needs to be initialised
at run time.

Any caller of a lookup function must still be prepared for the
possibility that the object returned is in a different table - it
might have been there for some time.

Note that this does NOT provide support for other uses of
NULLS_MARKERs such as allocating with SLAB_TYPESAFE_BY_RCU or changing
the key of an object and re-inserting it in the same table.
These could only be done safely if new objects were inserted
at the *start* of a hash chain, and that is not currently the case.

Signed-off-by: NeilBrown <neilb@suse.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-12-03 15:31:55 -08:00
Linus Torvalds 050cdc6c95 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) ICE, E1000, IGB, IXGBE, and I40E bug fixes from the Intel folks.

 2) Better fix for AB-BA deadlock in packet scheduler code, from Cong
    Wang.

 3) bpf sockmap fixes (zero sized key handling, etc.) from Daniel
    Borkmann.

 4) Send zero IPID in TCP resets and SYN-RECV state ACKs, to prevent
    attackers using it as a side-channel. From Eric Dumazet.

 5) Memory leak in mediatek bluetooth driver, from Gustavo A. R. Silva.

 6) Hook up rt->dst.input of ipv6 anycast routes properly, from Hangbin
    Liu.

 7) hns and hns3 bug fixes from Huazhong Tan.

 8) Fix RIF leak in mlxsw driver, from Ido Schimmel.

 9) iova range check fix in vhost, from Jason Wang.

10) Fix hang in do_tcp_sendpages() with tls, from John Fastabend.

11) More r8152 chips need to disable RX aggregation, from Kai-Heng Feng.

12) Memory exposure in TCA_U32_SEL handling, from Kees Cook.

13) TCP BBR congestion control fixes from Kevin Yang.

14) hv_netvsc, ignore non-PCI devices, from Stephen Hemminger.

15) qed driver fixes from Tomer Tayar.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (77 commits)
  net: sched: Fix memory exposure from short TCA_U32_SEL
  qed: fix spelling mistake "comparsion" -> "comparison"
  vhost: correctly check the iova range when waking virtqueue
  qlge: Fix netdev features configuration.
  net: macb: do not disable MDIO bus at open/close time
  Revert "net: stmmac: fix build failure due to missing COMMON_CLK dependency"
  net: macb: Fix regression breaking non-MDIO fixed-link PHYs
  mlxsw: spectrum_switchdev: Do not leak RIFs when removing bridge
  i40e: fix condition of WARN_ONCE for stat strings
  i40e: Fix for Tx timeouts when interface is brought up if DCB is enabled
  ixgbe: fix driver behaviour after issuing VFLR
  ixgbe: Prevent unsupported configurations with XDP
  ixgbe: Replace GFP_ATOMIC with GFP_KERNEL
  igb: Replace mdelay() with msleep() in igb_integrated_phy_loopback()
  igb: Replace GFP_ATOMIC with GFP_KERNEL in igb_sw_init()
  igb: Use an advanced ctx descriptor for launchtime
  e1000: ensure to free old tx/rx rings in set_ringparam()
  e1000: check on netif_running() before calling e1000_up()
  ixgb: use dma_zalloc_coherent instead of allocator/memset
  ice: Trivial formatting fixes
  ...
2018-08-27 11:59:39 -07:00
Davidlohr Bueso 2d22ecf6db lib/rhashtable: guarantee initial hashtable allocation
rhashtable_init() may fail due to -ENOMEM, thus making the entire api
unusable.  This patch removes this scenario, however unlikely.  In order
to guarantee memory allocation, this patch always ends up doing
GFP_KERNEL|__GFP_NOFAIL for both the tbl as well as
alloc_bucket_spinlocks().

Upon the first table allocation failure, we shrink the size to the
smallest value that makes sense and retry with __GFP_NOFAIL semantics.
With the defaults, this means that from 64 buckets, we retry with only 4.
Any later issues regarding performance due to collisions or larger table
resizing (when more memory becomes available) is the least of our
problems.

Link: http://lkml.kernel.org/r/20180712185241.4017-9-manfred@colorfullife.com
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:52 -07:00
Davidlohr Bueso 93f976b519 lib/rhashtable: simplify bucket_table_alloc()
As of ce91f6ee5b ("mm: kvmalloc does not fallback to vmalloc for
incompatible gfp flags") we can simplify the caller and trust kvzalloc()
to just do the right thing.  For the case of the GFP_ATOMIC context, we
can drop the __GFP_NORETRY flag for obvious reasons, and for the
__GFP_NOWARN case, however, it is changed such that the caller passes the
flag instead of making bucket_table_alloc() handle it.

This slightly changes the gfp flags passed on to nested_table_alloc() as
it will now also use GFP_ATOMIC | __GFP_NOWARN.  However, I consider this
a positive consequence as for the same reasons we want nowarn semantics in
bucket_table_alloc().

[manfred@colorfullife.com: commit id extended to 12 digits, line wraps updated]
Link: http://lkml.kernel.org/r/20180712185241.4017-8-manfred@colorfullife.com
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Kees Cook <keescook@chromium.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:52 -07:00
Yue Haibing ab08dcd724 rhashtable: remove duplicated include from rhashtable.c
Remove duplicated include.

Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-20 19:18:50 -07:00
David S. Miller c4c5551df1 Merge ra.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux
All conflicts were trivial overlapping changes, so reasonably
easy to resolve.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-20 21:17:12 -07:00
Davidlohr Bueso 107d01f5ba lib/rhashtable: consider param->min_size when setting initial table size
rhashtable_init() currently does not take into account the user-passed
min_size parameter unless param->nelem_hint is set as well. As such,
the default size (number of buckets) will always be HASH_DEFAULT_SIZE
even if the smallest allowed size is larger than that. Remediate this
by unconditionally calling into rounded_hashtable_size() and handling
things accordingly.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-18 13:27:43 -07:00
Taehee Yoo 0026129c86 rhashtable: add restart routine in rhashtable_free_and_destroy()
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>
2018-07-09 16:28:51 -07:00
Rishabh Bhatnagar c643ecf354 lib: rhashtable: Correct self-assignment in rhashtable.c
In file lib/rhashtable.c line 777, skip variable is assigned to
itself. The following error was observed:

lib/rhashtable.c:777:41: warning: explicitly assigning value of
variable of type 'int' to itself [-Wself-assign] error, forbidden
warning: rhashtable.c:777
This error was found when compiling with Clang 6.0. Change it to iter->skip.

Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-03 23:25:37 +09:00
NeilBrown c0690016a7 rhashtable: clean up dereference of ->future_tbl.
Using rht_dereference_bucket() to dereference
->future_tbl looks like a type error, and could be confusing.
Using rht_dereference_rcu() to test a pointer for NULL
adds an unnecessary barrier - rcu_access_pointer() is preferred
for NULL tests when no lock is held.

This uses 3 different ways to access ->future_tbl.
- if we know the mutex is held, use rht_dereference()
- if we don't hold the mutex, and are only testing for NULL,
  use rcu_access_pointer()
- otherwise (using RCU protection for true dereference),
  use rht_dereference_rcu().

Note that this includes a simplification of the call to
rhashtable_last_table() - we don't do an extra dereference
before the call any more.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-22 13:43:28 +09:00
NeilBrown 0ad66449aa rhashtable: use cmpxchg() to protect ->future_tbl.
Rather than borrowing one of the bucket locks to
protect ->future_tbl updates, use cmpxchg().
This gives more freedom to change how bucket locking
is implemented.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-22 13:43:27 +09:00
NeilBrown 5af68ef733 rhashtable: simplify nested_table_alloc() and rht_bucket_nested_insert()
Now that we don't use the hash value or shift in nested_table_alloc()
there is room for simplification.
We only need to pass a "is this a leaf" flag to nested_table_alloc(),
and don't need to track as much information in
rht_bucket_nested_insert().

Note there is another minor cleanup in nested_table_alloc() here.
The number of elements in a page of "union nested_tables" is most naturally

  PAGE_SIZE / sizeof(ntbl[0])

The previous code had

  PAGE_SIZE / sizeof(ntbl[0].bucket)

which happens to be the correct value only because the bucket uses all
the space in the union.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-22 13:43:27 +09:00
NeilBrown 9b4f64a227 rhashtable: simplify INIT_RHT_NULLS_HEAD()
The 'ht' and 'hash' arguments to INIT_RHT_NULLS_HEAD() are
no longer used - so drop them.  This allows us to also
remove the nhash argument from nested_table_alloc().

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-22 13:43:27 +09:00
NeilBrown 9f9a707738 rhashtable: remove nulls_base and related code.
This "feature" is unused, undocumented, and untested and so doesn't
really belong.  A patch is under development to properly implement
support for detecting when a search gets diverted down a different
chain, which the common purpose of nulls markers.

This patch actually fixes a bug too.  The table resizing allows a
table to grow to 2^31 buckets, but the hash is truncated to 27 bits -
any growth beyond 2^27 is wasteful an ineffective.

This patch results in NULLS_MARKER(0) being used for all chains,
and leaves the use of rht_is_a_null() to test for it.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-22 13:43:27 +09:00
NeilBrown 0eb71a9da5 rhashtable: split rhashtable.h
Due to the use of rhashtables in net namespaces,
rhashtable.h is included in lots of the kernel,
so a small changes can required a large recompilation.
This makes development painful.

This patch splits out rhashtable-types.h which just includes
the major type declarations, and does not include (non-trivial)
inline code.  rhashtable.h is no longer included by anything
in the include/ directory.
Common include files only include rhashtable-types.h so a large
recompilation is only triggered when that changes.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-22 13:43:27 +09:00
NeilBrown 5d240a8936 rhashtable: improve rhashtable_walk stability when stop/start used.
When a walk of an rhashtable is interrupted with rhastable_walk_stop()
and then rhashtable_walk_start(), the location to restart from is based
on a 'skip' count in the current hash chain, and this can be incorrect
if insertions or deletions have happened.  This does not happen when
the walk is not stopped and started as iter->p is a placeholder which
is safe to use while holding the RCU read lock.

In rhashtable_walk_start() we can revalidate that 'p' is still in the
same hash chain.  If it isn't then the current method is still used.

With this patch, if a rhashtable walker ensures that the current
object remains in the table over a stop/start period (possibly by
elevating the reference count if that is sufficient), it can be sure
that a walk will not miss objects that were in the hashtable for the
whole time of the walk.

rhashtable_walk_start() may not find the object even though it is
still in the hashtable if a rehash has moved it to a new table.  In
this case it will (eventually) get -EAGAIN and will need to proceed
through the whole table again to be sure to see everything at least
once.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-24 13:21:46 -04:00
NeilBrown b41cc04b66 rhashtable: reset iter when rhashtable_walk_start sees new table
The documentation claims that when rhashtable_walk_start_check()
detects a resize event, it will rewind back to the beginning
of the table.  This is not true.  We need to set ->slot and
->skip to be zero for it to be true.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-24 13:21:45 -04:00
NeilBrown 82266e98dd rhashtable: Revise incorrect comment on r{hl, hash}table_walk_enter()
Neither rhashtable_walk_enter() or rhltable_walk_enter() sleep, though
they do take a spinlock without irq protection.
So revise the comments to accurately state the contexts in which
these functions can be called.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-24 13:21:45 -04:00
Eric Dumazet ae6da1f503 rhashtable: add schedule points
Rehashing and destroying large hash table takes a lot of time,
and happens in process context. It is safe to add cond_resched()
in rhashtable_rehash_table() and rhashtable_free_and_destroy()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-31 23:25:39 -04:00
Paul Blakey d3dcf8eb61 rhashtable: Fix rhlist duplicates insertion
When inserting duplicate objects (those with the same key),
current rhlist implementation messes up the chain pointers by
updating the bucket pointer instead of prev next pointer to the
newly inserted node. This causes missing elements on removal and
travesal.

Fix that by properly updating pprev pointer to point to
the correct rhash_head next pointer.

Issue: 1241076
Change-Id: I86b2c140bcb4aeb10b70a72a267ff590bb2b17e7
Fixes: ca26893f05 ('rhashtable: Add rhlist interface')
Signed-off-by: Paul Blakey <paulb@mellanox.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-03-07 10:44:02 -05:00
Tom Herbert 64e0cd0d35 rhashtable: Call library function alloc_bucket_locks
To allocate the array of bucket locks for the hash table we now
call library function alloc_bucket_spinlocks. This function is
based on the old alloc_bucket_locks in rhashtable and should
produce the same effect.

Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-11 09:58:39 -05:00
Tom Herbert 2db54b475a rhashtable: Add rhastable_walk_peek
This function is like rhashtable_walk_next except that it only returns
the current element in the inter and does not advance the iter.

This patch also creates __rhashtable_walk_find_next. It finds the next
element in the table when the entry cached in iter is NULL or at the end
of a slot. __rhashtable_walk_find_next is called from
rhashtable_walk_next and rhastable_walk_peek.

end_of_table is an added field to the iter structure. This indicates
that the end of table was reached (walker.tbl being NULL is not a
sufficient condition for end of table).

Signed-off-by: Tom Herbert <tom@quantonium.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-11 09:58:38 -05:00
Tom Herbert 97a6ec4ac0 rhashtable: Change rhashtable_walk_start to return void
Most callers of rhashtable_walk_start don't care about a resize event
which is indicated by a return value of -EAGAIN. So calls to
rhashtable_walk_start are wrapped wih code to ignore -EAGAIN. Something
like this is common:

       ret = rhashtable_walk_start(rhiter);
       if (ret && ret != -EAGAIN)
               goto out;

Since zero and -EAGAIN are the only possible return values from the
function this check is pointless. The condition never evaluates to true.

This patch changes rhashtable_walk_start to return void. This simplifies
code for the callers that ignore -EAGAIN. For the few cases where the
caller cares about the resize event, particularly where the table can be
walked in mulitple parts for netlink or seq file dump, the function
rhashtable_walk_start_check has been added that returns -EAGAIN on a
resize event.

Signed-off-by: Tom Herbert <tom@quantonium.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-11 09:58:38 -05:00
Andreas Gruenbacher 0647169cf9 rhashtable: Documentation tweak
Clarify that rhashtable_walk_{stop,start} will not reset the iterator to
the beginning of the hash table.  Confusion between rhashtable_walk_enter
and rhashtable_walk_start has already lead to a bug.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-19 15:18:33 -07:00
Linus Torvalds 52f6c588c7 Add wait_for_random_bytes() and get_random_*_wait() functions so that
callers can more safely get random bytes if they can block until the
 CRNG is initialized.
 
 Also print a warning if get_random_*() is called before the CRNG is
 initialized.  By default, only one single-line warning will be printed
 per boot.  If CONFIG_WARN_ALL_UNSEEDED_RANDOM is defined, then a
 warning will be printed for each function which tries to get random
 bytes before the CRNG is initialized.  This can get spammy for certain
 architecture types, so it is not enabled by default.
 -----BEGIN PGP SIGNATURE-----
 
 iQEzBAABCAAdFiEEK2m5VNv+CHkogTfJ8vlZVpUNgaMFAllqXNUACgkQ8vlZVpUN
 gaPtAgf/aUbXZuWYsDQzslHsbzEWi+qz4QgL885/w4L00pEImTTp91Q06SDxWhtB
 KPvGnZHS3IofxBh2DC+6AwN6dPMoWDCfYhhO6po3FSz0DiPRIQCTuvOb8fhKY1X7
 rTdDq2xtDxPGxJ25bMJtlrgzH2XlXPpVyPUeoc9uh87zUK5aesXpUn9kBniRexoz
 ume+M/cDzPKkwNQpbLq8vzhNjoWMVv0FeW2akVvrjkkWko8nZLZ0R/kIyKQlRPdG
 LZDXcz0oTHpDS6+ufEo292ZuWm2IGer2YtwHsKyCAsyEWsUqBz2yurtkSj3mAVyC
 hHafyS+5WNaGdgBmg0zJxxwn5qxxLg==
 =ua7p
 -----END PGP SIGNATURE-----

Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random

Pull random updates from Ted Ts'o:
 "Add wait_for_random_bytes() and get_random_*_wait() functions so that
  callers can more safely get random bytes if they can block until the
  CRNG is initialized.

  Also print a warning if get_random_*() is called before the CRNG is
  initialized. By default, only one single-line warning will be printed
  per boot. If CONFIG_WARN_ALL_UNSEEDED_RANDOM is defined, then a
  warning will be printed for each function which tries to get random
  bytes before the CRNG is initialized. This can get spammy for certain
  architecture types, so it is not enabled by default"

* tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
  random: reorder READ_ONCE() in get_random_uXX
  random: suppress spammy warnings about unseeded randomness
  random: warn when kernel uses unseeded randomness
  net/route: use get_random_int for random counter
  net/neighbor: use get_random_u32 for 32-bit hash random
  rhashtable: use get_random_u32 for hash_rnd
  ceph: ensure RNG is seeded before using
  iscsi: ensure RNG is seeded before use
  cifs: use get_random_u32 for 32-bit lock random
  random: add get_random_{bytes,u32,u64,int,long,once}_wait family
  random: add wait_for_random_bytes() API
2017-07-15 12:44:02 -07:00
Michal Hocko 12e8fd6fd3 lib/rhashtable.c: use kvzalloc() in bucket_table_alloc() when possible
bucket_table_alloc() can be currently called with GFP_KERNEL or
GFP_ATOMIC.  For the former we basically have an open coded kvzalloc()
while the later only uses kzalloc().  Let's simplify the code a bit by
the dropping the open coded path and replace it with kvzalloc().

Link: http://lkml.kernel.org/r/20170531155145.17111-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:35 -07:00
Jason A. Donenfeld d48ad080ec rhashtable: use get_random_u32 for hash_rnd
This is much faster and just as secure. It also has the added benefit of
probably returning better randomness at early-boot on systems with
architectural RNGs.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-06-19 22:06:28 -04:00
Michal Hocko 43ca5bc4f7 lib/rhashtable.c: simplify a strange allocation pattern
alloc_bucket_locks allocation pattern is quite unusual.  We are
preferring vmalloc when CONFIG_NUMA is enabled.  The rationale is that
vmalloc will respect the memory policy of the current process and so the
backing memory will get distributed over multiple nodes if the requester
is configured properly.  At least that is the intention, in reality
rhastable is shrunk and expanded from a kernel worker so no mempolicy
can be assumed.

Let's just simplify the code and use kvmalloc helper, which is a
transparent way to use kmalloc with vmalloc fallback, if the caller is
allowed to block and use the flag otherwise.

Link: http://lkml.kernel.org/r/20170306103032.2540-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08 17:15:12 -07:00
Florian Westphal 48e75b4306 rhashtable: compact struct rhashtable_params
By using smaller datatypes this (rather large) struct shrinks considerably
(80 -> 48 bytes on x86_64).

As this is embedded in other structs, this also rerduces size of several
others, e.g. cls_fl_head or nft_hash.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-01 16:22:40 -04:00
Herbert Xu 2d2ab658d2 rhashtable: Do not lower max_elems when max_size is zero
The commit 6d684e5469 ("rhashtable: Cap total number of entries
to 2^31") breaks rhashtable users that do not set max_size.  This
is because when max_size is zero max_elems is also incorrectly set
to zero instead of 2^31.

This patch fixes it by only lowering max_elems when max_size is not
zero.

Fixes: 6d684e5469 ("rhashtable: Cap total number of entries to 2^31")
Reported-by: Florian Fainelli <f.fainelli@gmail.com>
Reported-by: kernel test robot <fengguang.wu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-28 10:14:09 -04:00
Herbert Xu 6d684e5469 rhashtable: Cap total number of entries to 2^31
When max_size is not set or if it set to a sufficiently large
value, the nelems counter can overflow.  This would cause havoc
with the automatic shrinking as it would then attempt to fit a
huge number of entries into a tiny hash table.

This patch fixes this by adding max_elems to struct rhashtable
to cap the number of elements.  This is set to 2^31 as nelems is
not a precise count.  This is sufficiently smaller than UINT_MAX
that it should be safe.

When max_size is set max_elems will be lowered to at most twice
max_size as is the status quo.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-27 11:48:24 -04:00
Florian Westphal 038a3e858d rhashtable: remove insecure_max_entries param
no users in the tree, insecure_max_entries is always set to
ht->p.max_size * 2 in rhtashtable_init().

Replace only spot that uses it with a ht->p.max_size check.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-26 14:39:24 -04:00
Florian Westphal 5f8ddeab10 rhashtable: remove insecure_elasticity
commit 83e7e4ce9e ("mac80211: Use rhltable instead of rhashtable")
removed the last user that made use of 'insecure_elasticity' parameter,
i.e. the default of 16 is used everywhere.

Replace it with a constant.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-18 13:49:14 -04:00
Ingo Molnar b2d0910310 sched/headers: Prepare to use <linux/rcuupdate.h> instead of <linux/rculist.h> in <linux/sched.h>
We don't actually need the full rculist.h header in sched.h anymore,
we will be able to include the smaller rcupdate.h header instead.

But first update code that relied on the implicit header inclusion.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:38 +01:00
Herbert Xu c4d2603dac rhashtable: Fix RCU dereference annotation in rht_bucket_nested
The current annotation is wrong as it says that we're only called
under spinlock.  In fact it should be marked as under either
spinlock or RCU read lock.

Fixes: da20420f83 ("rhashtable: Add nested tables")
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-26 21:33:43 -05:00
Herbert Xu ca435407ba rhashtable: Fix use before NULL check in bucket_table_free
Dan Carpenter reported a use before NULL check bug in the function
bucket_table_free.  In fact we don't need the NULL check at all as
no caller can provide a NULL argument.  So this patch fixes this by
simply removing it.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-26 21:32:57 -05:00
Herbert Xu da20420f83 rhashtable: Add nested tables
This patch adds code that handles GFP_ATOMIC kmalloc failure on
insertion.  As we cannot use vmalloc, we solve it by making our
hash table nested.  That is, we allocate single pages at each level
and reach our desired table size by nesting them.

When a nested table is created, only a single page is allocated
at the top-level.  Lower levels are allocated on demand during
insertion.  Therefore for each insertion to succeed, only two
(non-consecutive) pages are needed.

After a nested table is created, a rehash will be scheduled in
order to switch to a vmalloced table as soon as possible.  Also,
the rehash code will never rehash into a nested table.  If we
detect a nested table during a rehash, the rehash will be aborted
and a new rehash will be scheduled.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-17 12:28:35 -05:00
Herbert Xu ca26893f05 rhashtable: Add rhlist interface
The insecure_elasticity setting is an ugly wart brought out by
users who need to insert duplicate objects (that is, distinct
objects with identical keys) into the same table.

In fact, those users have a much bigger problem.  Once those
duplicate objects are inserted, they don't have an interface to
find them (unless you count the walker interface which walks
over the entire table).

Some users have resorted to doing a manual walk over the hash
table which is of course broken because they don't handle the
potential existence of multiple hash tables.  The result is that
they will break sporadically when they encounter a hash table
resize/rehash.

This patch provides a way out for those users, at the expense
of an extra pointer per object.  Essentially each object is now
a list of objects carrying the same key.  The hash table will
only see the lists so nothing changes as far as rhashtable is
concerned.

To use this new interface, you need to insert a struct rhlist_head
into your objects instead of struct rhash_head.  While the hash
table is unchanged, for type-safety you'll need to use struct
rhltable instead of struct rhashtable.  All the existing interfaces
have been duplicated for rhlist, including the hash table walker.

One missing feature is nulls marking because AFAIK the only potential
user of it does not need duplicate objects.  Should anyone need
this it shouldn't be too hard to add.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-20 04:43:36 -04:00
David S. Miller 60175ccdf4 Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next
Pablo Neira Ayuso says:

====================
Netfilter updates for net-next

The following patchset contains Netfilter updates for your net-next
tree.  Most relevant updates are the removal of per-conntrack timers to
use a workqueue/garbage collection approach instead from Florian
Westphal, the hash and numgen expression for nf_tables from Laura
Garcia, updates on nf_tables hash set to honor the NLM_F_EXCL flag,
removal of ip_conntrack sysctl and many other incremental updates on our
Netfilter codebase.

More specifically, they are:

1) Retrieve only 4 bytes to fetch ports in case of non-linear skb
   transport area in dccp, sctp, tcp, udp and udplite protocol
   conntrackers, from Gao Feng.

2) Missing whitespace on error message in physdev match, from Hangbin Liu.

3) Skip redundant IPv4 checksum calculation in nf_dup_ipv4, from Liping Zhang.

4) Add nf_ct_expires() helper function and use it, from Florian Westphal.

5) Replace opencoded nf_ct_kill() call in IPVS conntrack support, also
   from Florian.

6) Rename nf_tables set implementation to nft_set_{name}.c

7) Introduce the hash expression to allow arbitrary hashing of selector
   concatenations, from Laura Garcia Liebana.

8) Remove ip_conntrack sysctl backward compatibility code, this code has
   been around for long time already, and we have two interfaces to do
   this already: nf_conntrack sysctl and ctnetlink.

9) Use nf_conntrack_get_ht() helper function whenever possible, instead
   of opencoding fetch of hashtable pointer and size, patch from Liping Zhang.

10) Add quota expression for nf_tables.

11) Add number generator expression for nf_tables, this supports
    incremental and random generators that can be combined with maps,
    very useful for load balancing purpose, again from Laura Garcia Liebana.

12) Fix a typo in a debug message in FTP conntrack helper, from Colin Ian King.

13) Introduce a nft_chain_parse_hook() helper function to parse chain hook
    configuration, this is used by a follow up patch to perform better chain
    update validation.

14) Add rhashtable_lookup_get_insert_key() to rhashtable and use it from the
    nft_set_hash implementation to honor the NLM_F_EXCL flag.

15) Missing nulls check in nf_conntrack from nf_conntrack_tuple_taken(),
    patch from Florian Westphal.

16) Don't use the DYING bit to know if the conntrack event has been already
    delivered, instead a state variable to track event re-delivery
    states, also from Florian.

17) Remove the per-conntrack timer, use the workqueue approach that was
    discussed during the NFWS, from Florian Westphal.

18) Use the netlink conntrack table dump path to kill stale entries,
    again from Florian.

19) Add a garbage collector to get rid of stale conntracks, from
    Florian.

20) Reschedule garbage collector if eviction rate is high.

21) Get rid of the __nf_ct_kill_acct() helper.

22) Use ARPHRD_ETHER instead of hardcoded 1 from ARP logger.

23) Make nf_log_set() interface assertive on unsupported families.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-06 12:45:26 -07:00
David S. Miller 6abdd5f593 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
All three conflicts were cases of simple overlapping
changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-30 00:54:02 -04:00
Eric Dumazet 9dbeea7f08 rhashtable: fix a memory leak in alloc_bucket_locks()
If vmalloc() was successful, do not attempt a kmalloc_array()

Fixes: 4cf0b354d9 ("rhashtable: avoid large lock-array allocations")
Reported-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Florian Westphal <fw@strlen.de>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-26 21:59:53 -07:00
Pablo Neira Ayuso 5ca8cc5bf1 rhashtable: add rhashtable_lookup_get_insert_key()
This patch modifies __rhashtable_insert_fast() so it returns the
existing object that clashes with the one that you want to insert.
In case the object is successfully inserted, NULL is returned.
Otherwise, you get an error via ERR_PTR().

This patch adapts the existing callers of __rhashtable_insert_fast()
so they handle this new logic, and it adds a new
rhashtable_lookup_get_insert_key() interface to fetch this existing
object.

nf_tables needs this change to improve handling of EEXIST cases via
honoring the NLM_F_EXCL flag and by checking if the data part of the
mapping matches what we have.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-08-26 17:29:41 +02:00
Herbert Xu 246779dd09 rhashtable: Remove GFP flag from rhashtable_walk_init
The commit 8f6fd83c6c ("rhashtable:
accept GFP flags in rhashtable_walk_init") added a GFP flag argument
to rhashtable_walk_init because some users wish to use the walker
in an unsleepable context.

In fact we don't need to allocate memory in rhashtable_walk_init
at all.  The walker is always paired with an iterator so we could
just stash ourselves there.

This patch does that by introducing a new enter function to replace
the existing init function.  This way we don't have to churn all
the existing users again.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-19 14:40:24 -07:00
Vegard Nossum 12311959ec rhashtable: fix shift by 64 when shrinking
I got this:

    ================================================================================
    UBSAN: Undefined behaviour in ./include/linux/log2.h:63:13
    shift exponent 64 is too large for 64-bit type 'long unsigned int'
    CPU: 1 PID: 721 Comm: kworker/1:1 Not tainted 4.8.0-rc1+ #87
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
    Workqueue: events rht_deferred_worker
     0000000000000000 ffff88011661f8d8 ffffffff82344f50 0000000041b58ab3
     ffffffff84f98000 ffffffff82344ea4 ffff88011661f900 ffff88011661f8b0
     0000000000000001 ffff88011661f6b8 dffffc0000000000 ffffffff867f7640
    Call Trace:
     [<ffffffff82344f50>] dump_stack+0xac/0xfc
     [<ffffffff82344ea4>] ? _atomic_dec_and_lock+0xc4/0xc4
     [<ffffffff8242f5b8>] ubsan_epilogue+0xd/0x8a
     [<ffffffff82430c41>] __ubsan_handle_shift_out_of_bounds+0x255/0x29a
     [<ffffffff824309ec>] ? __ubsan_handle_out_of_bounds+0x180/0x180
     [<ffffffff84003436>] ? nl80211_req_set_reg+0x256/0x2f0
     [<ffffffff812112ba>] ? print_context_stack+0x8a/0x160
     [<ffffffff81200031>] ? amd_pmu_reset+0x341/0x380
     [<ffffffff823af808>] rht_deferred_worker+0x1618/0x1790
     [<ffffffff823af808>] ? rht_deferred_worker+0x1618/0x1790
     [<ffffffff823ae1f0>] ? rhashtable_jhash2+0x370/0x370
     [<ffffffff8134c12d>] ? process_one_work+0x6fd/0x1970
     [<ffffffff8134c1cf>] process_one_work+0x79f/0x1970
     [<ffffffff8134c12d>] ? process_one_work+0x6fd/0x1970
     [<ffffffff8134ba30>] ? try_to_grab_pending+0x4c0/0x4c0
     [<ffffffff8134d564>] ? worker_thread+0x1c4/0x1340
     [<ffffffff8134d8ff>] worker_thread+0x55f/0x1340
     [<ffffffff845e904f>] ? __schedule+0x4df/0x1d40
     [<ffffffff8134d3a0>] ? process_one_work+0x1970/0x1970
     [<ffffffff8134d3a0>] ? process_one_work+0x1970/0x1970
     [<ffffffff813642f7>] kthread+0x237/0x390
     [<ffffffff813640c0>] ? __kthread_parkme+0x280/0x280
     [<ffffffff845f8c93>] ? _raw_spin_unlock_irq+0x33/0x50
     [<ffffffff845f95df>] ret_from_fork+0x1f/0x40
     [<ffffffff813640c0>] ? __kthread_parkme+0x280/0x280
    ================================================================================

roundup_pow_of_two() is undefined when called with an argument of 0, so
let's avoid the call and just fall back to ht->p.min_size (which should
never be smaller than HASH_MIN_SIZE).

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-15 11:10:09 -07:00
Florian Westphal 4cf0b354d9 rhashtable: avoid large lock-array allocations
Sander reports following splat after netfilter nat bysrc table got
converted to rhashtable:

swapper/0: page allocation failure: order:3, mode:0x2084020(GFP_ATOMIC|__GFP_COMP)
 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.8.0-rc1 [..]
 [<ffffffff811633ed>] warn_alloc_failed+0xdd/0x140
 [<ffffffff811638b1>] __alloc_pages_nodemask+0x3e1/0xcf0
 [<ffffffff811a72ed>] alloc_pages_current+0x8d/0x110
 [<ffffffff8117cb7f>] kmalloc_order+0x1f/0x70
 [<ffffffff811aec19>] __kmalloc+0x129/0x140
 [<ffffffff8146d561>] bucket_table_alloc+0xc1/0x1d0
 [<ffffffff8146da1d>] rhashtable_insert_rehash+0x5d/0xe0
 [<ffffffff819fcfff>] nf_nat_setup_info+0x2ef/0x400

The failure happens when allocating the spinlock array.
Even with GFP_KERNEL its unlikely for such a large allocation
to succeed.

Thomas Graf pointed me at inet_ehash_locks_alloc(), so in addition
to adding NOWARN for atomic allocations this also makes the bucket-array
sizing more conservative.

In commit 095dc8e0c3 ("tcp: fix/cleanup inet_ehash_locks_alloc()"),
Eric Dumazet says: "Budget 2 cache lines per cpu worth of 'spinlocks'".
IOW, consider size needed by a single spinlock when determining
number of locks per cpu.  So with 64 byte per cacheline and 4 byte per
spinlock this gives 32 locks per cpu.

Resulting size of the lock-array (sizeof(spinlock) == 4):

cpus:    1   2   4   8   16   32   64
old:    1k  1k  4k  8k  16k  16k  16k
new:   128 256 512  1k   2k   4k   8k

8k allocation should have decent chance of success even
with GFP_ATOMIC, and should not fail with GFP_KERNEL.

With 72-byte spinlock (LOCKDEP):
cpus :   1   2
old:    9k 18k
new:   ~2k ~4k

Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Suggested-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-14 21:12:57 -07:00
Bob Copeland 8f6fd83c6c rhashtable: accept GFP flags in rhashtable_walk_init
In certain cases, the 802.11 mesh pathtable code wants to
iterate over all of the entries in the forwarding table from
the receive path, which is inside an RCU read-side critical
section.  Enable walks inside atomic sections by allowing
GFP_ATOMIC allocations for the walker state.

Change all existing callsites to pass in GFP_KERNEL.

Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Bob Copeland <me@bobcopeland.com>
[also adjust gfs2/glock.c and rhashtable tests]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2016-04-05 10:56:32 +02:00
David S. Miller c07f30ad68 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-12-31 18:20:10 -05:00
Herbert Xu 179ccc0a73 rhashtable: Kill harmless RCU warning in rhashtable_walk_init
The commit c6ff526829 ("rhashtable:
Fix walker list corruption") causes a suspicious RCU usage warning
because we no longer hold ht->mutex when we dereference ht->tbl.

However, this is a false positive because we now hold ht->lock
which also guarantees that ht->tbl won't disppear from under us.

This patch kills the warning by using rcu_dereference_protected.

Reported-by: kernel test robot <ying.huang@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-18 23:44:18 -05:00
David S. Miller b3e0d3d7ba Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/geneve.c

Here we had an overlapping change, where in 'net' the extraneous stats
bump was being removed whilst in 'net-next' the final argument to
udp_tunnel6_xmit_skb() was being changed.

Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-17 22:08:28 -05:00
Herbert Xu c6ff526829 rhashtable: Fix walker list corruption
The commit ba7c95ea38 ("rhashtable:
Fix sleeping inside RCU critical section in walk_stop") introduced
a new spinlock for the walker list.  However, it did not convert
all existing users of the list over to the new spin lock.  Some
continued to use the old mutext for this purpose.  This obviously
led to corruption of the list.

The fix is to use the spin lock everywhere where we touch the list.

This also allows us to do rcu_rad_lock before we take the lock in
rhashtable_walk_start.  With the old mutex this would've deadlocked
but it's safe with the new spin lock.

Fixes: ba7c95ea38 ("rhashtable: Fix sleeping inside RCU...")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-16 11:13:14 -05:00