On Sat, Aug 08, 2020 at 03:57:33PM -0700, Jack Leadford wrote:
> Hello!
>
> Thanks to Jason for getting this conversation back on track.
>
> Yes: in general, {} or a partial initializer /will/ zero padding bits.
>
> However, there is a bug in some versions of GCC where {} will /not/ zero
>
On Sat, Aug 08, 2020 at 03:57:33PM -0700, Jack Leadford wrote:
> Hello!
>
> Thanks to Jason for getting this conversation back on track.
>
> Yes: in general, {} or a partial initializer /will/ zero padding bits.
>
> However, there is a bug in some versions of GCC where {} will /not/ zero
> padding
Hello!
Thanks to Jason for getting this conversation back on track.
Yes: in general, {} or a partial initializer /will/ zero padding bits.
However, there is a bug in some versions of GCC where {} will /not/ zero
padding bits; actually, Jason's test program in this mail
On Sun, Aug 02, 2020 at 03:45:40PM -0700, Joe Perches wrote:
> On Sun, 2020-08-02 at 19:28 -0300, Jason Gunthorpe wrote:
> > On Sun, Aug 02, 2020 at 03:23:58PM -0700, Joe Perches wrote:
> > > On Sun, 2020-08-02 at 19:10 -0300, Jason Gunthorpe wrote:
> > > > On Sat, Aug 01, 2020 at 08:38:33AM
Ah, thanks. We've had a bunch of discussions about these leaks but I
wasn't aware of this.
regards,
dan carpenter
On Sun, Aug 02, 2020 at 03:45:40PM -0700, Joe Perches wrote:
> On Sun, 2020-08-02 at 19:28 -0300, Jason Gunthorpe wrote:
> > On Sun, Aug 02, 2020 at 03:23:58PM -0700, Joe Perches wrote:
> > > On Sun, 2020-08-02 at 19:10 -0300, Jason Gunthorpe wrote:
> > > > On Sat, Aug 01, 2020 at 08:38:33AM
On Sun, 2020-08-02 at 19:28 -0300, Jason Gunthorpe wrote:
> On Sun, Aug 02, 2020 at 03:23:58PM -0700, Joe Perches wrote:
> > On Sun, 2020-08-02 at 19:10 -0300, Jason Gunthorpe wrote:
> > > On Sat, Aug 01, 2020 at 08:38:33AM +0300, Leon Romanovsky wrote:
> > >
> > > > I'm using {} instead of {0}
On Sun, Aug 02, 2020 at 03:23:58PM -0700, Joe Perches wrote:
> On Sun, 2020-08-02 at 19:10 -0300, Jason Gunthorpe wrote:
> > On Sat, Aug 01, 2020 at 08:38:33AM +0300, Leon Romanovsky wrote:
> >
> > > I'm using {} instead of {0} because of this GCC bug.
> > >
On Sun, 2020-08-02 at 19:10 -0300, Jason Gunthorpe wrote:
> On Sat, Aug 01, 2020 at 08:38:33AM +0300, Leon Romanovsky wrote:
>
> > I'm using {} instead of {0} because of this GCC bug.
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53119
>
> This is why the {} extension exists..
There is no
On Sat, Aug 01, 2020 at 08:38:33AM +0300, Leon Romanovsky wrote:
> I'm using {} instead of {0} because of this GCC bug.
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53119
This is why the {} extension exists..
Jason
On Sat, Aug 01, 2020 at 11:00:26AM +0300, Dan Carpenter wrote:
> > Without an actual example where this doesn't work right it is hard to
> > say anything more..
>
> Here is the example that set off the recent patches:
>
> https://lkml.org/lkml/2020/7/27/199
Oh, that is something completely
On Fri, Jul 31, 2020 at 03:27:12PM -0300, Jason Gunthorpe wrote:
> On Fri, Jul 31, 2020 at 07:19:24PM +0200, Greg Kroah-Hartman wrote:
>
> > > I tried for a bit and didn't find a way to get even old gcc 4.4 to not
> > > initialize the holes.
> >
> > Odd, so it is just the "= {0};" that does not
On Fri, Jul 31, 2020 at 07:19:24PM +0200, Greg Kroah-Hartman wrote:
> On Fri, Jul 31, 2020 at 11:36:04AM -0300, Jason Gunthorpe wrote:
> > On Fri, Jul 31, 2020 at 04:21:48PM +0200, Greg Kroah-Hartman wrote:
> >
> > > > The spec was updated in C11 to require zero'ing padding when doing
> > > >
From: Peilin Ye
Date: Thu, 30 Jul 2020 15:20:26 -0400
> rds_notify_queue_get() is potentially copying uninitialized kernel stack
> memory to userspace since the compiler may leave a 4-byte hole at the end
> of `cmsg`.
>
> In 2016 we tried to fix this issue by doing `= { 0 };` on `cmsg`, which
>
On Fri, Jul 31, 2020 at 07:19:24PM +0200, Greg Kroah-Hartman wrote:
> > I tried for a bit and didn't find a way to get even old gcc 4.4 to not
> > initialize the holes.
>
> Odd, so it is just the "= {0};" that does not zero out the holes?
Nope, it seems to work fine too. I tried a number of
On Fri, Jul 31, 2020 at 11:36:04AM -0300, Jason Gunthorpe wrote:
> On Fri, Jul 31, 2020 at 04:21:48PM +0200, Greg Kroah-Hartman wrote:
>
> > > The spec was updated in C11 to require zero'ing padding when doing
> > > partial initialization of aggregates (eg = {})
> > >
> > > """if it is an
On Fri, Jul 31, 2020 at 04:21:48PM +0200, Greg Kroah-Hartman wrote:
> > The spec was updated in C11 to require zero'ing padding when doing
> > partial initialization of aggregates (eg = {})
> >
> > """if it is an aggregate, every member is initialized (recursively)
> > according to these rules,
On Fri, Jul 31, 2020 at 11:04:52AM -0300, Jason Gunthorpe wrote:
> On Fri, Jul 31, 2020 at 07:33:33AM +0200, Greg Kroah-Hartman wrote:
> > On Fri, Jul 31, 2020 at 07:33:06AM +0200, Greg Kroah-Hartman wrote:
> > > On Fri, Jul 31, 2020 at 07:53:01AM +0300, Leon Romanovsky wrote:
> > > > On Thu, Jul
On Fri, Jul 31, 2020 at 07:33:33AM +0200, Greg Kroah-Hartman wrote:
> On Fri, Jul 31, 2020 at 07:33:06AM +0200, Greg Kroah-Hartman wrote:
> > On Fri, Jul 31, 2020 at 07:53:01AM +0300, Leon Romanovsky wrote:
> > > On Thu, Jul 30, 2020 at 03:20:26PM -0400, Peilin Ye wrote:
> > > >
> On 31 Jul 2020, at 13:59, Greg Kroah-Hartman
> wrote:
>
> On Fri, Jul 31, 2020 at 01:14:09PM +0200, Håkon Bugge wrote:
>>
>>
>>> On 31 Jul 2020, at 11:59, Dan Carpenter wrote:
>>>
>>> On Fri, Jul 31, 2020 at 07:53:01AM +0300, Leon Romanovsky wrote:
On Thu, Jul 30, 2020 at
On Fri, Jul 31, 2020 at 01:14:09PM +0200, Håkon Bugge wrote:
>
>
> > On 31 Jul 2020, at 11:59, Dan Carpenter wrote:
> >
> > On Fri, Jul 31, 2020 at 07:53:01AM +0300, Leon Romanovsky wrote:
> >> On Thu, Jul 30, 2020 at 03:20:26PM -0400, Peilin Ye wrote:
> >>> rds_notify_queue_get() is
> On 31 Jul 2020, at 11:59, Dan Carpenter wrote:
>
> On Fri, Jul 31, 2020 at 07:53:01AM +0300, Leon Romanovsky wrote:
>> On Thu, Jul 30, 2020 at 03:20:26PM -0400, Peilin Ye wrote:
>>> rds_notify_queue_get() is potentially copying uninitialized kernel stack
>>> memory to userspace since the
On Fri, Jul 31, 2020 at 07:53:01AM +0300, Leon Romanovsky wrote:
> On Thu, Jul 30, 2020 at 03:20:26PM -0400, Peilin Ye wrote:
> > rds_notify_queue_get() is potentially copying uninitialized kernel stack
> > memory to userspace since the compiler may leave a 4-byte hole at the end
> > of `cmsg`.
>
Sakari, JFYI. I remember during some reviews we have a discussion
about {0} vs {} and surprisingly they are not an equivalent.
On Fri, Jul 31, 2020 at 10:00 AM Leon Romanovsky wrote:
> On Fri, Jul 31, 2020 at 09:29:27AM +0300, Andy Shevchenko wrote:
> > On Friday, July 31, 2020, Greg
On Fri, Jul 31, 2020 at 09:29:27AM +0300, Andy Shevchenko wrote:
> On Friday, July 31, 2020, Greg Kroah-Hartman
> wrote:
>
> > On Fri, Jul 31, 2020 at 07:33:06AM +0200, Greg Kroah-Hartman wrote:
> > > On Fri, Jul 31, 2020 at 07:53:01AM +0300, Leon Romanovsky wrote:
> > > > On Thu, Jul 30, 2020 at
On Fri, Jul 31, 2020 at 07:53:01AM +0300, Leon Romanovsky wrote:
> On Thu, Jul 30, 2020 at 03:20:26PM -0400, Peilin Ye wrote:
> > rds_notify_queue_get() is potentially copying uninitialized kernel stack
> > memory to userspace since the compiler may leave a 4-byte hole at the end
> > of `cmsg`.
>
On Fri, Jul 31, 2020 at 07:33:06AM +0200, Greg Kroah-Hartman wrote:
> On Fri, Jul 31, 2020 at 07:53:01AM +0300, Leon Romanovsky wrote:
> > On Thu, Jul 30, 2020 at 03:20:26PM -0400, Peilin Ye wrote:
> > > rds_notify_queue_get() is potentially copying uninitialized kernel stack
> > > memory to
On Thu, Jul 30, 2020 at 03:20:26PM -0400, Peilin Ye wrote:
> rds_notify_queue_get() is potentially copying uninitialized kernel stack
> memory to userspace since the compiler may leave a 4-byte hole at the end
> of `cmsg`.
>
> In 2016 we tried to fix this issue by doing `= { 0 };` on `cmsg`, which
On 7/30/20 12:20 PM, Peilin Ye wrote:
rds_notify_queue_get() is potentially copying uninitialized kernel stack
memory to userspace since the compiler may leave a 4-byte hole at the end
of `cmsg`.
In 2016 we tried to fix this issue by doing `= { 0 };` on `cmsg`, which
unfortunately does not
rds_notify_queue_get() is potentially copying uninitialized kernel stack
memory to userspace since the compiler may leave a 4-byte hole at the end
of `cmsg`.
In 2016 we tried to fix this issue by doing `= { 0 };` on `cmsg`, which
unfortunately does not always initialize that 4-byte hole. Fix it
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