Il Thu, Jan 18, 2007 at 12:26:12PM -0700, Brandon Beck ha scritto:
> [EMAIL PROTECTED] wrote:
> >Hi,
> >
> >(added Cc to suspend-devel and the author of swap-offset)
> >
> >On Thursday, 18 January 2007 08:32, you wrote:
> >>Hello Rafael,
> >> Is the resume offset ever supposed to be a negative number? I run
> >>swap-offset /var/swap on a 2.6.20-rc5 kernel and get -270968. I don't
> >>really want to mess up my system here.
> >
> >No, it should be positive.
> >
> >What is the size of blocks on your /var?
>
> For good or for ill, I have a single partition (sda1) and I recently
> created the swapfile for use with uswsusp, so it is presumably towards the
> end of the disk. On /dev/sda1 I have 76920416 1K blocks with 1299176
> available (99% use :-)
Internally address_space_operation (->bmap) uses a sector_t (u64), but
the ioctl truncates it to a 32bit signed integer. With 1K blocks it
gives a limit of 2TB (or 4TB casting back to unsigned int).
What may overflow is this (swap-offset.c:110):
first_block * blk_size
The following patch should fix it:
- Kernel uses unsigned quantify for block number, pass an unsigned int
to the ioctl.
- Use 64bit math to avoid overflow.
---
swap-offset.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
Index: swap-offset.c
===================================================================
RCS file: /cvsroot/suspend/suspend/swap-offset.c,v
retrieving revision 1.3
diff -u -r1.3 swap-offset.c
--- swap-offset.c 12 Nov 2006 21:32:09 -0000 1.3
+++ swap-offset.c 18 Jan 2007 20:44:06 -0000
@@ -23,7 +23,8 @@
#define SWAP_SIG_SIZE 10
int main(int argc, char **argv) {
- int block, last_block, first_block, blocks_per_page;
+ unsigned int block, last_block, first_block, blocks_per_page;
+ unsigned int offset;
int size, blk_size;
int fd;
int i;
@@ -107,7 +108,8 @@
"be used for suspension.\n");
err = EINVAL;
} else {
- printf("resume offset = %d\n", first_block * blk_size /
page_size);
+ offset = (unsigned long long)first_block * blk_size / page_size;
+ printf("resume offset = %u\n", offset);
}
out:
Luca
--
Se il destino di un uomo e` annegare, anneghera` anche in un bicchier
d'acqua.
Proverbio yddish
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