Mailing List Archive: [PATCH 6/7] btrfs: Promote to unsigned long long before shifting

[PATCH 6/7] btrfs: Promote to unsigned long long before shifting

Oct 4, 2020, 12:15 PM

Post #1 of 5 (13 views)

On 32-bit systems, this shift will overflow for files larger than 4GB.

Cc: stable@vger.kernel.org
Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
fs/btrfs/raid56.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 255490f42b5d..5ee0a53301bd 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -1089,7 +1089,7 @@ static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
u64 disk_start;

stripe = &rbio->bbio->stripes[stripe_nr];
- disk_start = stripe->physical + (page_index << PAGE_SHIFT);
+ disk_start = stripe->physical + ((loff_t)page_index << PAGE_SHIFT);

/* if the device is missing, just fail this stripe */
if (!stripe->dev->bdev)
--
2.28.0

Re: [PATCH 6/7] btrfs: Promote to unsigned long long before shifting [ In reply to ]

josef at toxicpanda

Oct 9, 2020, 8:15 AM

Post #2 of 5 (13 views)

Permalink

On 10/4/20 2:04 PM, Matthew Wilcox (Oracle) wrote:
> On 32-bit systems, this shift will overflow for files larger than 4GB.
>
> Cc: stable@vger.kernel.org
> Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef

Re: [PATCH 6/7] btrfs: Promote to unsigned long long before shifting [ In reply to ]

dsterba at suse

Oct 26, 2020, 10:15 AM

Post #3 of 5 (13 views)

Permalink

On Sun, Oct 04, 2020 at 07:04:27PM +0100, Matthew Wilcox (Oracle) wrote:
> On 32-bit systems, this shift will overflow for files larger than 4GB.
>
> Cc: stable@vger.kernel.org
> Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
> fs/btrfs/raid56.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
> index 255490f42b5d..5ee0a53301bd 100644
> --- a/fs/btrfs/raid56.c
> +++ b/fs/btrfs/raid56.c
> @@ -1089,7 +1089,7 @@ static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
> u64 disk_start;
>
> stripe = &rbio->bbio->stripes[stripe_nr];
> - disk_start = stripe->physical + (page_index << PAGE_SHIFT);
> + disk_start = stripe->physical + ((loff_t)page_index << PAGE_SHIFT);

It seems that this patch is mechanical replacement. If you check the
callers, the page_index is passed from an int that iterates over bits
set in an unsigned long (bitmap). The result won't overflow.

Re: [PATCH 6/7] btrfs: Promote to unsigned long long before shifting [ In reply to ]

willy at infradead

Oct 26, 2020, 10:15 AM

Post #4 of 5 (13 views)

Permalink

On Mon, Oct 26, 2020 at 05:35:46PM +0100, David Sterba wrote:
> On Sun, Oct 04, 2020 at 07:04:27PM +0100, Matthew Wilcox (Oracle) wrote:
> > On 32-bit systems, this shift will overflow for files larger than 4GB.
> >
> > Cc: stable@vger.kernel.org
> > Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
> > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > ---
> > fs/btrfs/raid56.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
> > index 255490f42b5d..5ee0a53301bd 100644
> > --- a/fs/btrfs/raid56.c
> > +++ b/fs/btrfs/raid56.c
> > @@ -1089,7 +1089,7 @@ static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
> > u64 disk_start;
> >
> > stripe = &rbio->bbio->stripes[stripe_nr];
> > - disk_start = stripe->physical + (page_index << PAGE_SHIFT);
> > + disk_start = stripe->physical + ((loff_t)page_index << PAGE_SHIFT);
>
> It seems that this patch is mechanical replacement. If you check the
> callers, the page_index is passed from an int that iterates over bits
> set in an unsigned long (bitmap). The result won't overflow.

Not mechanical, but I clearly made mistakes. Will you pick up the
patches which actually fix bugs?

Re: [PATCH 6/7] btrfs: Promote to unsigned long long before shifting [ In reply to ]

dsterba at suse

Oct 26, 2020, 10:15 AM

Post #5 of 5 (13 views)

Permalink

On Mon, Oct 26, 2020 at 04:44:42PM +0000, Matthew Wilcox wrote:
> On Mon, Oct 26, 2020 at 05:35:46PM +0100, David Sterba wrote:
> > On Sun, Oct 04, 2020 at 07:04:27PM +0100, Matthew Wilcox (Oracle) wrote:
> > > On 32-bit systems, this shift will overflow for files larger than 4GB.
> > >
> > > Cc: stable@vger.kernel.org
> > > Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
> > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > > ---
> > > fs/btrfs/raid56.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
> > > index 255490f42b5d..5ee0a53301bd 100644
> > > --- a/fs/btrfs/raid56.c
> > > +++ b/fs/btrfs/raid56.c
> > > @@ -1089,7 +1089,7 @@ static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
> > > u64 disk_start;
> > >
> > > stripe = &rbio->bbio->stripes[stripe_nr];
> > > - disk_start = stripe->physical + (page_index << PAGE_SHIFT);
> > > + disk_start = stripe->physical + ((loff_t)page_index << PAGE_SHIFT);
> >
> > It seems that this patch is mechanical replacement. If you check the
> > callers, the page_index is passed from an int that iterates over bits
> > set in an unsigned long (bitmap). The result won't overflow.
>
> Not mechanical, but I clearly made mistakes. Will you pick up the
> patches which actually fix bugs?

Yes, I just replied to the first patch, that does fix an overflow.