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module: statically initialize init section freeing data

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.

Daniel Jordan committed 6 years ago

Commit fdf09ab1 parent 14721ad1 file · +3 −10Browse files

Showing the changes to kernel/module.c (1 of 1 file). Show all

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kernel/module.c+3−10
@@ -91,8 +91,9 @@ EXPORT_SYMBOL_GPL(module_mutex); · 90 unmodified lines
9191 static LIST_HEAD(modules);
9292
9393 /* Work queue for freeing init sections in success case */
94−static struct work_struct init_free_wq;
95−static struct llist_head init_free_list;
94+static void do_free_init(struct work_struct *w);
95+static DECLARE_WORK(init_free_wq, do_free_init);
96+static LLIST_HEAD(init_free_list);
9697
9798 #ifdef CONFIG_MODULES_TREE_LOOKUP
9899
@@ -3582,14 +3583,6 @@ static void do_free_init(struct work_struct *w) · 3483 unmodified lines
35823583 }
35833584 }
35843585
3585−static int __init modules_wq_init(void)
3586−{
3587− INIT_WORK(&init_free_wq, do_free_init);
3588− init_llist_head(&init_free_list);
3589− return 0;
3590−}
3591−module_init(modules_wq_init);
3592−
35933586 /*
35943587 * This is where the real work happens.
35953588 *