Messages in this thread | | | Date | Sun, 07 Jul 2013 15:31:35 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH v2] swap: warn when a swap area overflows the maximum size |
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On 07/07/2013 03:13 PM, Raymond Jennings wrote: > Turned the comparison around for clarity of "bigger than" > > No semantic changes, if it still compiles it should do the same thing so > I've omitted the testing this time. Will be happy to retest if required > but I'm on an atom 330 and kernel rebuilds are a nightmare.
Added CC: Andrew Morton, since this should probably go into -mm :)
> ---- > > swap: warn when a swap area overflows the maximum size > > It is possible to swapon a swap area that is too big for the pte width > to handle. > > Presently this failure happens silently. > > Instead, emit a diagnostic to warn the user. > > Signed-off-by: Raymond Jennings <shentino@gmail.com> > Acked-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Reviewed-by: Rik van Riel <riel@redhat.com>
> diff --git a/mm/swapfile.c b/mm/swapfile.c > index 36af6ee..5a4ce53 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -1953,6 +1953,12 @@ static unsigned long read_swap_header(struct > swap_info_struct *p, > */ > maxpages = swp_offset(pte_to_swp_entry( > swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1; > + if (swap_header->info.last_page > maxpages) { > + printk(KERN_WARNING > + "Truncating oversized swap area, only using %luk > out of %luk > \n", > + maxpages << (PAGE_SHIFT - 10), > + swap_header->info.last_page << (PAGE_SHIFT - > 10)); > + } > if (maxpages > swap_header->info.last_page) { > maxpages = swap_header->info.last_page + 1; > /* p->max is an unsigned int: don't overflow it */ > > ---- > > Testing results, root prompt commands and kernel log messages: > > # lvresize /dev/system/swap --size 16G > # mkswap /dev/system/swap > # swapon /dev/system/swap > > Jul 7 04:27:22 warfang kernel: Adding 16777212k swap > on /dev/mapper/system-swap. Priority:-1 extents:1 across:16777212k > > # lvresize /dev/system/swap --size 16G > # mkswap /dev/system/swap > # swapon /dev/system/swap > > Jul 7 04:27:22 warfang kernel: Truncating oversized swap area, only > using 33554432k out of 67108860k > Jul 7 04:27:22 warfang kernel: Adding 33554428k swap > on /dev/mapper/system-swap. Priority:-1 extents:1 across:33554428k > >
-- All rights reversed
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