I was seeing a lot of these:
BUG: sleeping function called from invalid context at mm/slab.h:388
in_atomic(): 0, irqs_disabled(): 0, pid: 14971, name: trinity-c2
Preemption disabled at:[<ffffffff819bcd46>] rhashtable_walk_start+0x46/0x150
[<ffffffff81149abb>] preempt_count_add+0x1fb/0x280
[<ffffffff83295722>] _raw_spin_lock+0x12/0x40
[<ffffffff811aac87>] console_unlock+0x2f7/0x930
[<ffffffff811ab5bb>] vprintk_emit+0x2fb/0x520
[<ffffffff811aba6a>] vprintk_default+0x1a/0x20
[<ffffffff812c171a>] printk+0x94/0xb0
[<ffffffff811d6ed0>] print_stack_trace+0xe0/0x170
[<ffffffff8115835e>] ___might_sleep+0x3be/0x460
[<ffffffff81158490>] __might_sleep+0x90/0x1a0
[<ffffffff8139b823>] kmem_cache_alloc+0x153/0x1e0
[<ffffffff819bca1e>] rhashtable_walk_init+0xfe/0x2d0
[<ffffffff82ec64de>] sctp_transport_walk_start+0x1e/0x60
[<ffffffff82edd8ad>] sctp_transport_seq_start+0x4d/0x150
[<ffffffff8143a82b>] seq_read+0x27b/0x1180
[<ffffffff814f97fc>] proc_reg_read+0xbc/0x180
[<ffffffff813d471b>] __vfs_read+0xdb/0x610
[<ffffffff813d4d3a>] vfs_read+0xea/0x2d0
[<ffffffff813d615b>] SyS_pread64+0x11b/0x150
[<ffffffff8100334c>] do_syscall_64+0x19c/0x410
[<ffffffff832960a5>] return_from_SYSCALL_64+0x0/0x6a
[<ffffffffffffffff>] 0xffffffffffffffff
Apparently we always need to call rhashtable_walk_stop(), even when
rhashtable_walk_start() fails:
* rhashtable_walk_start - Start a hash table walk
* @iter: Hash table iterator
*
* Start a hash table walk. Note that we take the RCU lock in all
* cases including when we return an error. So you must always call
* rhashtable_walk_stop to clean up.
otherwise we never call rcu_read_unlock() and we get the splat above.
Fixes: 53fa1036 ("sctp: fix some rhashtable functions using in sctp proc/diag")
See-also: 53fa1036 ("sctp: fix some rhashtable functions using in sctp proc/diag")
See-also: f2dba9c6 ("rhashtable: Introduce rhashtable_walk_*")
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: stable@vger.kernel.org
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
5fc382d875