linux-kernel - Race condition: calling remove_proc_entry in cleanup_module (module

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Date:	Tue, 4 Sep 2007 18:39:33 +0200
From:	"anon... anon.al" <anon.asdf@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: Race condition: calling remove_proc_entry in cleanup_module (module_exit) while someone's using procfile

Hi!

There is a race condition if an instance is executing "__exit
device_exit" and calls remove_proc_entry, while someone is still using
the procfile, right?.

static void __exit device_exit(void)
{
  // what if the procfile is still in use?
  remove_proc_entry(PROC_FILE_NAME, &proc_root);
}

To remove this race condition, the code in "__exit device_exit" must
a) be sure that no other instance is in procfile functions
b) call remove_proc_entry before any other instance accesses the procfile

*** Is this at all possible if a race-condition is to be avoided?
If yes: which mechanism can be used?

Thanks -Albert
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