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From: Ingo Oeser <netdev@axxeo•de>
To: Pavel Emelyanov <xemul@openvz•org>
Cc: Johannes Berg <johannes@sipsolutions•net>,
	"John W. Linville" <linville@tuxdriver•com>,
	David Miller <davem@davemloft•net>,
	linux-wireless@vger•kernel.org,
	Linux Netdev List <netdev@vger•kernel.org>
Subject: Re: [PATCH 1/4][MAC80211]: Fix GFP_KERNEL allocation under read lock.
Date: Tue, 6 May 2008 18:40:37 +0200	[thread overview]
Message-ID: <200805061840.37713.netdev@axxeo.de> (raw)
In-Reply-To: <48206F4C.5050105@openvz.org>

Hi Pavel,

regarding:

[PATCH 1/4][MAC80211]: Fix GFP_KERNEL allocation under read lock
[PATCH 2/4][MAC80211]: Fix not checked kmalloc() result

Pavel Emelyanov schrieb:
> The mesh_path_add() read-locks the pathtbl_resize_lock and calls
> kmalloc with GFP_KERNEL mask.
> 
> Fix it and move the endadd2 label lower. It should be _before_ the
> if() beyond, but it makes no sense for it being there, so I move it
> right after this if().

What about doing both allocations in succession to local variables,
share the failure path if an error occours an kfree them unconditionally 
like this?

new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
new_mpath = kzalloc(sizeof(struct mesh_path), GFP_KERNEL);
if (!new_node || !new_mpath) {
	kfree(new_mpath);
	kfree(new_node);
	atomic_dec(&sdata->u.sta.mpaths);
	err = -ENOMEM;
	goto endadd2;
}
...
read_lock(...);
...

Rationale: Allocations are always likely to fail/succeed in close succession.


Best Regards

Ingo Oeser

  reply	other threads:[~2008-05-06 16:41 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-06 14:46 [PATCH 1/4][MAC80211]: Fix GFP_KERNEL allocation under read lock Pavel Emelyanov
2008-05-06 16:40 ` Ingo Oeser [this message]
2008-05-06 17:46   ` Pavel Emelyanov
     [not found]     ` <4820997E.1070305-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>
2008-05-06 20:40       ` David Miller
2008-05-07  5:54         ` Pavel Emelyanov
2008-05-07  5:59           ` David Miller
2008-05-08 18:51             ` John W. Linville
     [not found]               ` <20080508185123.GA7250-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org>
2008-05-08 18:53                 ` John W. Linville
     [not found]   ` <200805061840.37713.netdev-BkyiQQGWkgE@public.gmane.org>
2008-05-06 21:12     ` Johannes Berg

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