Messages in this thread | | | Date | Mon, 14 Aug 2006 15:43:56 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] Fix memory leak in vc_resize/vc_allocate |
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On Thu, 10 Aug 2006 15:22:21 +0100 Catalin Marinas <catalin.marinas@arm.com> wrote:
> From: Catalin Marinas <catalin.marinas@arm.com> > > Memory leaks can happen in the vc_resize() function in drivers/char/vt.c > because of the vc->vc_screenbuf variable overriding in vc_allocate(). The > kmemleak reported trace is as follows: > > <__kmalloc> > <vc_resize> > <fbcon_init> > <visual_init> > <vc_allocate> > <con_open> > <tty_open> > <chrdev_open> > > This patch no longer allocates a screen buffer in vc_allocate() if it was > already allocated by vc_resize(). > > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> > --- > > drivers/char/vt.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/drivers/char/vt.c b/drivers/char/vt.c > index da7e66a..31c8b32 100644 > --- a/drivers/char/vt.c > +++ b/drivers/char/vt.c > @@ -730,7 +730,8 @@ int vc_allocate(unsigned int currcons) / > visual_init(vc, currcons, 1); > if (!*vc->vc_uni_pagedir_loc) > con_set_default_unimap(vc); > - vc->vc_screenbuf = kmalloc(vc->vc_screenbuf_size, GFP_KERNEL); > + if (!vc->vc_kmalloced) > + vc->vc_screenbuf = kmalloc(vc->vc_screenbuf_size, GFP_KERNEL); > if (!vc->vc_screenbuf) { > kfree(vc); > vc_cons[currcons].d = NULL;
hm. Maybe. I'd worry that the memory at vc->vc_screenbuf isn't of the correct size and this patch will convert a leak into a buffer overrun.
Also, what's up with this, in vc_resize()?
if (vc->vc_kmalloced) kfree(vc->vc_screenbuf); vc->vc_screenbuf = newscreen; vc->vc_kmalloced = 1;
if vc->vc_kmalloced means "there is kmalloced memory at vc->vc_screenbuf" then this is wrong.
This code is all pretty twisty and I fear touching it. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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