Comment 3 for bug 1526811

Looks like the fix triggered another issue, so we need to see how upstream fixes this one.

Kernel test robot picked up a bug from this fix:

FYI, we noticed the below changes on

https://github.com/0day-ci/linux
Herbert-Xu/rhashtable-Fix-walker-list-corruption/20151216-164833
commit f9f51b8070be3e829100614a7372b219723b864f ("rhashtable: Fix walker
list corruption")

[ 8.933376] ===============================
[ 8.933376] ===============================
[ 8.934629] [ INFO: suspicious RCU usage. ]
[ 8.934629] [ INFO: suspicious RCU usage. ]
[ 8.935941] 4.4.0-rc3-00995-gf9f51b8 #2 Not tainted
[ 8.935941] 4.4.0-rc3-00995-gf9f51b8 #2 Not tainted
[ 8.937494] -------------------------------
[ 8.937494] -------------------------------
[ 8.938818] lib/rhashtable.c:504 suspicious
rcu_dereference_protected() usage!
[ 8.938818] lib/rhashtable.c:504 suspicious
rcu_dereference_protected() usage!
[ 8.941705]
[ 8.941705] other info that might help us debug this:
[ 8.941705]
[ 8.941705]
[ 8.941705] other info that might help us debug this:
[ 8.941705]
[ 8.944161]
[ 8.944161] rcu_scheduler_active = 1, debug_locks = 0
[ 8.944161]
[ 8.944161] rcu_scheduler_active = 1, debug_locks = 0
[ 8.946244] 1 lock held by swapper/0/1:
[ 8.946244] 1 lock held by swapper/0/1:
[ 8.947463] #0:
[ 8.947463] #0: (
(&(&ht->lock)->rlock&(&ht->lock)->rlock){+.+...}){+.+...}, at: , at:
[<ffffffff814b8900>] rhashtable_walk_init+0x70/0x150
[<ffffffff814b8900>] rhashtable_walk_init+0x70/0x150
[ 8.950428]
[ 8.950428] stack backtrace:
[ 8.950428]
[ 8.950428] stack backtrace:
[ 8.951770] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
4.4.0-rc3-00995-gf9f51b8 #2
[ 8.951770] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
4.4.0-rc3-00995-gf9f51b8 #2
[ 8.954245] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Debian-1.8.2-1 04/01/2014
[ 8.954245] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Debian-1.8.2-1 04/01/2014
[ 8.956973] 0000000000000001
[ 8.956973] 0000000000000001 ffff880078393d30 ffff880078393d30
ffffffff81493238 ffffffff81493238 ffff88007838c040 ffff88007838c040

[ 8.959333] ffff880078393d60
[ 8.959333] ffff880078393d60 ffffffff8112cb9f ffffffff8112cb9f
ffff880078393da0 ffff880078393da0 ffffffff83e9d6c0 ffffffff83e9d6c0

[ 8.961684] ffffffff83e9d7f0
[ 8.961684] ffffffff83e9d7f0 ffff880061720e00 ffff880061720e00
ffff880078393d90 ffff880078393d90 ffffffff814b89c8 ffffffff814b89c8

[ 8.964148] Call Trace:
[ 8.964148] Call Trace:
[ 8.964955] [<ffffffff81493238>] dump_stack+0x7c/0xb4
[ 8.964955] [<ffffffff81493238>] dump_stack+0x7c/0xb4
[ 8.966728] [<ffffffff8112cb9f>] lockdep_rcu_suspicious+0x14f/0x1c0
[ 8.966728] [<ffffffff8112cb9f>] lockdep_rcu_suspicious+0x14f/0x1c0
[ 8.968753] [<ffffffff814b89c8>] rhashtable_walk_init+0x138/0x150
[ 8.968753] [<ffffffff814b89c8>] rhashtable_walk_init+0x138/0x150
[ 8.970567] [<ffffffff815021d8>] test_bucket_stats+0x22/0x17d
[ 8.970567] [<ffffffff815021d8>] test_bucket_stats+0x22/0x17d
[ 8.972682] [<ffffffff82dda0fa>] test_rhashtable+0xe0/0x12ac
[ 8.972682] [<ffffffff82dda0fa>] test_rhashtable+0xe0/0x12ac
[ 8.974746] [<ffffffff816157db>] ? get_random_bytes+0x2b/0x40
[ 8.974746] [<ffffffff816157db>] ? get_random_bytes+0x2b/0x40
[ 8.976467] [<ffffffff814b6c33>] ? bucket_table_alloc+0x173/0x280
[ 8.976467] [<ffffffff814b6c33>] ? bucket_table_alloc+0x173/0x280
[ 8.978548] [<ffffffff82ddb3d5>] test_rht_init+0x10f/0x523
[ 8.978548] [<ffffffff82ddb3d5>] test_rht_init+0x10f/0x523
[ 8.980179] [<ffffffff82ddb2c6>] ? test_rhashtable+0x12ac/0x12ac
[ 8.980179] [<ffffffff82ddb2c6>] ? test_rhashtable+0x12ac/0x12ac
[ 8.982424] [<ffffffff82d9f757>] do_one_initcall+0x16b/0x248
[ 8.982424] [<ffffffff82d9f757>] do_one_initcall+0x16b/0x248
[ 8.984208] [<ffffffff82d9f9f8>] kernel_init_freeable+0x1c4/0x2b8
[ 8.984208] [<ffffffff82d9f9f8>] kernel_init_freeable+0x1c4/0x2b8
[ 8.986165] [<ffffffff81ed5b60>] ? rest_init+0x200/0x200
[ 8.986165] [<ffffffff81ed5b60>] ? rest_init+0x200/0x200
[ 8.987925] [<ffffffff81ed5b71>] kernel_init+0x11/0x190
[ 8.987925] [<ffffffff81ed5b71>] kernel_init+0x11/0x190
[ 8.989608] [<ffffffff81ee406f>] ret_from_fork+0x3f/0x70
[ 8.989608] [<ffffffff81ee406f>] ret_from_fork+0x3f/0x70
[ 8.991270] [<ffffffff81ed5b60>] ? rest_init+0x200/0x200
[ 8.991270] [<ffffffff81ed5b60>] ? rest_init+0x200/0x200

Thanks,
Kernel Test Robot