The server rdma_read_chunk_lcl() and rdma_read_chunk_frmr() functions
were not taking into account the initial page_offset when determining
the rdma read length. This resulted in a read who's starting address
and length exceeded the base/bounds of the frmr.
Most work loads don't tickle this bug apparently, but one test hit it
every time: building the linux kernel on a 16 core node with 'make -j
16 O=/mnt/0' where /mnt/0 is a ramdisk mounted via NFSRDMA.
This bug seems to only be tripped with devices having small fastreg page
list depths. I didn't see it with mlx4, for instance.
Fixes: 0bf4828983df ('svcrdma: refactor marshalling logic')
Signed-off-by: Steve Wise <[email protected]>
Tested-by: Chuck Lever <[email protected]>
---
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index cb51742..5f6ca47 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -136,7 +136,8 @@ int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
ctxt->direction = DMA_FROM_DEVICE;
ctxt->read_hdr = head;
pages_needed = min_t(int, pages_needed, xprt->sc_max_sge_rd);
- read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
+ read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
+ rs_length);
for (pno = 0; pno < pages_needed; pno++) {
int len = min_t(int, rs_length, PAGE_SIZE - pg_off);
@@ -235,7 +236,8 @@ int rdma_read_chunk_frmr(struct svcxprt_rdma *xprt,
ctxt->direction = DMA_FROM_DEVICE;
ctxt->frmr = frmr;
pages_needed = min_t(int, pages_needed, xprt->sc_frmr_pg_list_len);
- read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
+ read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
+ rs_length);
frmr->kva = page_address(rqstp->rq_arg.pages[pg_no]);
frmr->direction = DMA_FROM_DEVICE;
On 09/28/2015 05:46 PM, Steve Wise wrote:
> The server rdma_read_chunk_lcl() and rdma_read_chunk_frmr() functions
> were not taking into account the initial page_offset when determining
> the rdma read length. This resulted in a read who's starting address
> and length exceeded the base/bounds of the frmr.
>
> Most work loads don't tickle this bug apparently, but one test hit it
> every time: building the linux kernel on a 16 core node with 'make -j
> 16 O=/mnt/0' where /mnt/0 is a ramdisk mounted via NFSRDMA.
>
> This bug seems to only be tripped with devices having small fastreg page
> list depths. I didn't see it with mlx4, for instance.
Bruce, what's you're take on this? Do you want to push this through or
would you care if I push it through my tree?
> Fixes: 0bf4828983df ('svcrdma: refactor marshalling logic')
> Signed-off-by: Steve Wise <[email protected]>
> Tested-by: Chuck Lever <[email protected]>
> ---
>
> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 6 ++++--
> 1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> index cb51742..5f6ca47 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> @@ -136,7 +136,8 @@ int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
> ctxt->direction = DMA_FROM_DEVICE;
> ctxt->read_hdr = head;
> pages_needed = min_t(int, pages_needed, xprt->sc_max_sge_rd);
> - read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
> + read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
> + rs_length);
>
> for (pno = 0; pno < pages_needed; pno++) {
> int len = min_t(int, rs_length, PAGE_SIZE - pg_off);
> @@ -235,7 +236,8 @@ int rdma_read_chunk_frmr(struct svcxprt_rdma *xprt,
> ctxt->direction = DMA_FROM_DEVICE;
> ctxt->frmr = frmr;
> pages_needed = min_t(int, pages_needed, xprt->sc_frmr_pg_list_len);
> - read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
> + read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
> + rs_length);
>
> frmr->kva = page_address(rqstp->rq_arg.pages[pg_no]);
> frmr->direction = DMA_FROM_DEVICE;
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
Doug Ledford <[email protected]>
GPG KeyID: 0E572FDD
On Tue, Oct 06, 2015 at 01:44:25PM -0400, Doug Ledford wrote:
> On 09/28/2015 05:46 PM, Steve Wise wrote:
> > The server rdma_read_chunk_lcl() and rdma_read_chunk_frmr() functions
> > were not taking into account the initial page_offset when determining
> > the rdma read length. This resulted in a read who's starting address
> > and length exceeded the base/bounds of the frmr.
> >
> > Most work loads don't tickle this bug apparently, but one test hit it
> > every time: building the linux kernel on a 16 core node with 'make -j
> > 16 O=/mnt/0' where /mnt/0 is a ramdisk mounted via NFSRDMA.
> >
> > This bug seems to only be tripped with devices having small fastreg page
> > list depths. I didn't see it with mlx4, for instance.
>
> Bruce, what's you're take on this? Do you want to push this through or
> would you care if I push it through my tree?
Whoops, sorry, I meant to send a pull request for that last week. Uh, I
think I'll go ahead and do that now if it's OK with you.
--b.
>
> > Fixes: 0bf4828983df ('svcrdma: refactor marshalling logic')
> > Signed-off-by: Steve Wise <[email protected]>
> > Tested-by: Chuck Lever <[email protected]>
> > ---
> >
> > net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 6 ++++--
> > 1 files changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> > index cb51742..5f6ca47 100644
> > --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> > +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> > @@ -136,7 +136,8 @@ int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
> > ctxt->direction = DMA_FROM_DEVICE;
> > ctxt->read_hdr = head;
> > pages_needed = min_t(int, pages_needed, xprt->sc_max_sge_rd);
> > - read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
> > + read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
> > + rs_length);
> >
> > for (pno = 0; pno < pages_needed; pno++) {
> > int len = min_t(int, rs_length, PAGE_SIZE - pg_off);
> > @@ -235,7 +236,8 @@ int rdma_read_chunk_frmr(struct svcxprt_rdma *xprt,
> > ctxt->direction = DMA_FROM_DEVICE;
> > ctxt->frmr = frmr;
> > pages_needed = min_t(int, pages_needed, xprt->sc_frmr_pg_list_len);
> > - read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
> > + read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
> > + rs_length);
> >
> > frmr->kva = page_address(rqstp->rq_arg.pages[pg_no]);
> > frmr->direction = DMA_FROM_DEVICE;
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> > the body of a message to [email protected]
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
>
>
> --
> Doug Ledford <[email protected]>
> GPG KeyID: 0E572FDD
>
>
On 10/07/2015 01:01 PM, J. Bruce Fields wrote:
> On Tue, Oct 06, 2015 at 01:44:25PM -0400, Doug Ledford wrote:
>> On 09/28/2015 05:46 PM, Steve Wise wrote:
>>> The server rdma_read_chunk_lcl() and rdma_read_chunk_frmr() functions
>>> were not taking into account the initial page_offset when determining
>>> the rdma read length. This resulted in a read who's starting address
>>> and length exceeded the base/bounds of the frmr.
>>>
>>> Most work loads don't tickle this bug apparently, but one test hit it
>>> every time: building the linux kernel on a 16 core node with 'make -j
>>> 16 O=/mnt/0' where /mnt/0 is a ramdisk mounted via NFSRDMA.
>>>
>>> This bug seems to only be tripped with devices having small fastreg page
>>> list depths. I didn't see it with mlx4, for instance.
>>
>> Bruce, what's you're take on this? Do you want to push this through or
>> would you care if I push it through my tree?
>
> Whoops, sorry, I meant to send a pull request for that last week. Uh, I
> think I'll go ahead and do that now if it's OK with you.
Fine with me. I was just trying to make sure it didn't get forgotten ;-)
> --b.
>
>>
>>> Fixes: 0bf4828983df ('svcrdma: refactor marshalling logic')
>>> Signed-off-by: Steve Wise <[email protected]>
>>> Tested-by: Chuck Lever <[email protected]>
>>> ---
>>>
>>> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 6 ++++--
>>> 1 files changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
>>> index cb51742..5f6ca47 100644
>>> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
>>> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
>>> @@ -136,7 +136,8 @@ int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
>>> ctxt->direction = DMA_FROM_DEVICE;
>>> ctxt->read_hdr = head;
>>> pages_needed = min_t(int, pages_needed, xprt->sc_max_sge_rd);
>>> - read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
>>> + read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
>>> + rs_length);
>>>
>>> for (pno = 0; pno < pages_needed; pno++) {
>>> int len = min_t(int, rs_length, PAGE_SIZE - pg_off);
>>> @@ -235,7 +236,8 @@ int rdma_read_chunk_frmr(struct svcxprt_rdma *xprt,
>>> ctxt->direction = DMA_FROM_DEVICE;
>>> ctxt->frmr = frmr;
>>> pages_needed = min_t(int, pages_needed, xprt->sc_frmr_pg_list_len);
>>> - read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
>>> + read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
>>> + rs_length);
>>>
>>> frmr->kva = page_address(rqstp->rq_arg.pages[pg_no]);
>>> frmr->direction = DMA_FROM_DEVICE;
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
>>> the body of a message to [email protected]
>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>>
>>
>>
>> --
>> Doug Ledford <[email protected]>
>> GPG KeyID: 0E572FDD
>>
>>
>
>
--
Doug Ledford <[email protected]>
GPG KeyID: 0E572FDD
On Wed, Oct 07, 2015 at 01:33:05PM -0400, Doug Ledford wrote:
> On 10/07/2015 01:01 PM, J. Bruce Fields wrote:
> > On Tue, Oct 06, 2015 at 01:44:25PM -0400, Doug Ledford wrote:
> >> On 09/28/2015 05:46 PM, Steve Wise wrote:
> >>> The server rdma_read_chunk_lcl() and rdma_read_chunk_frmr() functions
> >>> were not taking into account the initial page_offset when determining
> >>> the rdma read length. This resulted in a read who's starting address
> >>> and length exceeded the base/bounds of the frmr.
> >>>
> >>> Most work loads don't tickle this bug apparently, but one test hit it
> >>> every time: building the linux kernel on a 16 core node with 'make -j
> >>> 16 O=/mnt/0' where /mnt/0 is a ramdisk mounted via NFSRDMA.
> >>>
> >>> This bug seems to only be tripped with devices having small fastreg page
> >>> list depths. I didn't see it with mlx4, for instance.
> >>
> >> Bruce, what's you're take on this? Do you want to push this through or
> >> would you care if I push it through my tree?
> >
> > Whoops, sorry, I meant to send a pull request for that last week. Uh, I
> > think I'll go ahead and do that now if it's OK with you.
>
> Fine with me. I was just trying to make sure it didn't get forgotten ;-)
Understood, thanks! I've sent the pull request.--b.
>
> > --b.
> >
> >>
> >>> Fixes: 0bf4828983df ('svcrdma: refactor marshalling logic')
> >>> Signed-off-by: Steve Wise <[email protected]>
> >>> Tested-by: Chuck Lever <[email protected]>
> >>> ---
> >>>
> >>> net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 6 ++++--
> >>> 1 files changed, 4 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> >>> index cb51742..5f6ca47 100644
> >>> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> >>> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> >>> @@ -136,7 +136,8 @@ int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
> >>> ctxt->direction = DMA_FROM_DEVICE;
> >>> ctxt->read_hdr = head;
> >>> pages_needed = min_t(int, pages_needed, xprt->sc_max_sge_rd);
> >>> - read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
> >>> + read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
> >>> + rs_length);
> >>>
> >>> for (pno = 0; pno < pages_needed; pno++) {
> >>> int len = min_t(int, rs_length, PAGE_SIZE - pg_off);
> >>> @@ -235,7 +236,8 @@ int rdma_read_chunk_frmr(struct svcxprt_rdma *xprt,
> >>> ctxt->direction = DMA_FROM_DEVICE;
> >>> ctxt->frmr = frmr;
> >>> pages_needed = min_t(int, pages_needed, xprt->sc_frmr_pg_list_len);
> >>> - read = min_t(int, pages_needed << PAGE_SHIFT, rs_length);
> >>> + read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
> >>> + rs_length);
> >>>
> >>> frmr->kva = page_address(rqstp->rq_arg.pages[pg_no]);
> >>> frmr->direction = DMA_FROM_DEVICE;
> >>>
> >>> --
> >>> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> >>> the body of a message to [email protected]
> >>> More majordomo info at http://vger.kernel.org/majordomo-info.html
> >>>
> >>
> >>
> >> --
> >> Doug Ledford <[email protected]>
> >> GPG KeyID: 0E572FDD
> >>
> >>
> >
> >
>
>
> --
> Doug Ledford <[email protected]>
> GPG KeyID: 0E572FDD
>
>