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module: statically initialize init section freeing data 

[ Upstream commit fdf09ab887 ]

Corentin hit the following workqueue warning when running with
CRYPTO_MANAGER_EXTRA_TESTS:

  WARNING: CPU: 2 PID: 147 at kernel/workqueue.c:1473 __queue_work+0x3b8/0x3d0
  Modules linked in: ghash_generic
  CPU: 2 PID: 147 Comm: modprobe Not tainted
      5.6.0-rc1-next-20200214-00068-g166c9264f0b1-dirty #545
  Hardware name: Pine H64 model A (DT)
  pc : __queue_work+0x3b8/0x3d0
  Call trace:
   __queue_work+0x3b8/0x3d0
   queue_work_on+0x6c/0x90
   do_init_module+0x188/0x1f0
   load_module+0x1d00/0x22b0

I wasn't able to reproduce on x86 or rpi 3b+.

This is

  WARN_ON(!list_empty(&work->entry))

from __queue_work(), and it happens because the init_free_wq work item
isn't initialized in time for a crypto test that requests the gcm
module.  Some crypto tests were recently moved earlier in boot as
explained in commit c4741b2305 ("crypto: run initcalls for generic
implementations earlier"), which went into mainline less than two weeks
before the Fixes commit.

Avoid the warning by statically initializing init_free_wq and the
corresponding llist.

Link: https://lore.kernel.org/lkml/20200217204803.GA13479@Red/
Fixes: 1a7b7d9220 ("modules: Use vmalloc special flag")
Reported-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Tested-on: sun50i-h6-pine-h64
Tested-on: imx8mn-ddr4-evk
Tested-on: sun50i-a64-bananapi-m64
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Daniel Jordan 2020-10-08 13:32:20 -04:00 committed by Greg Kroah-Hartman
parent b213999028
commit 1ed7508e68
1 changed files with 3 additions and 10 deletions
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13
kernel/module.c
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@ -88,8 +88,9 @@ EXPORT_SYMBOL_GPL(module_mutex);
static LIST_HEAD(modules);
/* Work queue for freeing init sections in success case */
static struct work_struct init_free_wq;
static struct llist_head init_free_list;
static void do_free_init(struct work_struct *w);
static DECLARE_WORK(init_free_wq, do_free_init);
static LLIST_HEAD(init_free_list);
#ifdef CONFIG_MODULES_TREE_LOOKUP
@ -3563,14 +3564,6 @@ static void do_free_init(struct work_struct *w)
}
}
static int __init modules_wq_init(void)
{
INIT_WORK(&init_free_wq, do_free_init);
init_llist_head(&init_free_list);
return 0;
}
module_init(modules_wq_init);
/*
* This is where the real work happens.
*