linux-kernel - Re: [PATCH] module: statically initialize init section freeing data

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Date:   Thu, 8 Oct 2020 21:17:17 -0700
From:   Eric Biggers <ebiggers@...nel.org>
To:     Daniel Jordan <daniel.m.jordan@...cle.com>
Cc:     Jessica Yu <jeyu@...nel.org>,
        Corentin Labbe <clabbe.montjoie@...il.com>,
        Rick Edgecombe <rick.p.edgecombe@...el.com>,
        Robin Murphy <robin.murphy@....com>,
        Will Deacon <will@...nel.org>, linux-crypto@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] module: statically initialize init section freeing data

On Thu, Oct 08, 2020 at 01:32:20PM -0400, Daniel Jordan wrote:
> 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 c4741b230597 ("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: 1a7b7d922081 ("modules: Use vmalloc special flag")
> Reported-by: Corentin Labbe <clabbe.montjoie@...il.com>
> Tested-by: Corentin Labbe <clabbe.montjoie@...il.com>
> Tested-on: sun50i-h6-pine-h64
> Tested-on: imx8mn-ddr4-evk
> Tested-on: sun50i-a64-bananapi-m64
> Signed-off-by: Daniel Jordan <daniel.m.jordan@...cle.com>

Looks good,

Reviewed-by: Eric Biggers <ebiggers@...gle.com>