Re: [dm-devel] [PATCH] dm-zoned: Fix overflow when converting zone ID to sectors
On Mon, 2017-07-03 at 15:44 +0900, Damien Le Moal wrote: > A zone ID is a 32 bits unsigned int which can overflow when doing the > bit shifts calculations in dmz_start_sect(). With a 256 MB zone size > drive, the overflow happens for a zone ID >= 8192. Does the data from this example apply to a sector size of 512 bytes only? Should this be mentioned in the patch description? Anyway, Reviewed-by: Bart Van Assche -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
Re: [dm-devel] [PATCH] dm-zoned: Fix overflow when converting zone ID to sectors
Bart, On 7/11/17 01:25, Bart Van Assche wrote: > On Mon, 2017-07-03 at 15:44 +0900, Damien Le Moal wrote: >> A zone ID is a 32 bits unsigned int which can overflow when doing the >> bit shifts calculations in dmz_start_sect(). With a 256 MB zone size >> drive, the overflow happens for a zone ID >= 8192. > > Does the data from this example apply to a sector size of 512 bytes only? > Should this be mentioned in the patch description? This is with BIO level 512B sectors addressing unit, which is used even with 4K LBA drives. So I did not mention it. I should have to be clear. Best regards. -- Damien Le Moal, Western Digital -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
[dm-devel] [PATCH] dm-zoned: Fix overflow when converting zone ID to sectors
A zone ID is a 32 bits unsigned int which can overflow when doing the
bit shifts calculations in dmz_start_sect(). With a 256 MB zone size
drive, the overflow happens for a zone ID >= 8192.
Fix this by casting the zone ID to a sector_t before doing the bit
shift. While at it, similarly fix dmz_start_block().
Signed-off-by: Damien Le Moal
---
drivers/md/dm-zoned-metadata.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
index 4618441c..884ff7c 100644
--- a/drivers/md/dm-zoned-metadata.c
+++ b/drivers/md/dm-zoned-metadata.c
@@ -191,12 +191,12 @@ unsigned int dmz_id(struct dmz_metadata *zmd, struct
dm_zone *zone)
sector_t dmz_start_sect(struct dmz_metadata *zmd, struct dm_zone *zone)
{
- return dmz_id(zmd, zone) << zmd->dev->zone_nr_sectors_shift;
+ return (sector_t)dmz_id(zmd, zone) << zmd->dev->zone_nr_sectors_shift;
}
sector_t dmz_start_block(struct dmz_metadata *zmd, struct dm_zone *zone)
{
- return dmz_id(zmd, zone) << zmd->dev->zone_nr_blocks_shift;
+ return (sector_t)dmz_id(zmd, zone) << zmd->dev->zone_nr_blocks_shift;
}
unsigned int dmz_nr_chunks(struct dmz_metadata *zmd)
--
2.9.4
--
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