[PATCH net-next 0/3] LiquidIO: avoid VM low memory crashes

[PATCH net-next 0/3] LiquidIO: avoid VM low memory crashes

[Felix Manlunas]

From: Rick Farrington <ricardo.farrington@cavium.com>

This patchset addresses issues brought about by low memory conditions
in a VM.  These conditions were only seen when VM's were intentionally
created with small amounts of memory (for stress testing).

1. Fix GPF in octeon_init_droq(); zero the allocated block 'recv_buf_list'.
   This prevents a GPF trying to access an invalid 'recv_buf_list[i]' entry
   in octeon_droq_destroy_ring_buffers() if init didn't alloc all entries.
2. Don't dereference a NULL ptr in octeon_droq_destroy_ring_buffers().
3. For defensive programming, zero the allocated block 'oct->droq[0]' in
   octeon_setup_output_queues() and 'oct->instr_queue[0]' in    
   octeon_setup_instr_queues().

 drivers/net/ethernet/cavium/liquidio/octeon_device.c | 8 ++++----
 drivers/net/ethernet/cavium/liquidio/octeon_droq.c   | 6 ++++--
 2 files changed, 8 insertions(+), 6 deletions(-)

-- 
1.8.3.1

[PATCH net-next 1/3] LiquidIO: lowmem: init allocated memory to 0

[Felix Manlunas]

From: Rick Farrington <ricardo.farrington@cavium.com>

Fix GPF in octeon_init_droq(); zero the allocated block 'recv_buf_list'.
This prevents a GPF trying to access an invalid 'recv_buf_list[i]' entry
in octeon_droq_destroy_ring_buffers() if init didn't alloc all entries.

Signed-off-by: Rick Farrington <ricardo.farrington@cavium.com>
Signed-off-by: Satanand Burla <satananda.burla@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
---
 drivers/net/ethernet/cavium/liquidio/octeon_droq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_droq.c b/drivers/net/ethernet/cavium/liquidio/octeon_droq.c
index 286be55..07c764d 100644
--- a/drivers/net/ethernet/cavium/liquidio/octeon_droq.c
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_droq.c
@@ -289,12 +289,12 @@ int octeon_init_droq(struct octeon_device *oct,
 	}
 
 	droq->recv_buf_list = (struct octeon_recv_buffer *)
-			      vmalloc_node(droq->max_count *
+			      vzalloc_node(droq->max_count *
 						OCT_DROQ_RECVBUF_SIZE,
 						numa_node);
 	if (!droq->recv_buf_list)
 		droq->recv_buf_list = (struct octeon_recv_buffer *)
-				      vmalloc(droq->max_count *
+				      vzalloc(droq->max_count *
 						OCT_DROQ_RECVBUF_SIZE);
 	if (!droq->recv_buf_list) {
 		dev_err(&oct->pci_dev->dev, "Output queue recv buf list alloc failed\n");
-- 
1.8.3.1

[PATCH net-next 2/3] LiquidIO: lowmem: do not dereference NULL ptr

[Felix Manlunas]

From: Rick Farrington <ricardo.farrington@cavium.com>

Don't dereference a NULL ptr in octeon_droq_destroy_ring_buffers().

Signed-off-by: Rick Farrington <ricardo.farrington@cavium.com>
Signed-off-by: Satanand Burla <satananda.burla@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
---
 drivers/net/ethernet/cavium/liquidio/octeon_droq.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_droq.c b/drivers/net/ethernet/cavium/liquidio/octeon_droq.c
index 07c764d..d868252 100644
--- a/drivers/net/ethernet/cavium/liquidio/octeon_droq.c
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_droq.c
@@ -145,6 +145,8 @@ static void octeon_droq_reset_indices(struct octeon_droq *droq)
 
 	for (i = 0; i < droq->max_count; i++) {
 		pg_info = &droq->recv_buf_list[i].pg_info;
+		if (!pg_info)
+			continue;
 
 		if (pg_info->dma)
 			lio_unmap_ring(oct->pci_dev,
-- 
1.8.3.1

[PATCH net-next 3/3] LiquidIO: lowmem: init allocated memory to 0

[Felix Manlunas]

From: Rick Farrington <ricardo.farrington@cavium.com>

For defensive programming, zero the allocated block 'oct->droq[0]' in
octeon_setup_output_queues() and 'oct->instr_queue[0]' in
octeon_setup_instr_queues().

Signed-off-by: Rick Farrington <ricardo.farrington@cavium.com>
Signed-off-by: Satanand Burla <satananda.burla@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
---
 drivers/net/ethernet/cavium/liquidio/octeon_device.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_device.c b/drivers/net/ethernet/cavium/liquidio/octeon_device.c
index 3b7cc93..087820b 100644
--- a/drivers/net/ethernet/cavium/liquidio/octeon_device.c
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_device.c
@@ -880,11 +880,11 @@ int octeon_setup_instr_queues(struct octeon_device *oct)
 
 	oct->num_iqs = 0;
 
-	oct->instr_queue[0] = vmalloc_node(sizeof(*oct->instr_queue[0]),
+	oct->instr_queue[0] = vzalloc_node(sizeof(*oct->instr_queue[0]),
 				numa_node);
 	if (!oct->instr_queue[0])
 		oct->instr_queue[0] =
-			vmalloc(sizeof(struct octeon_instr_queue));
+			vzalloc(sizeof(struct octeon_instr_queue));
 	if (!oct->instr_queue[0])
 		return 1;
 	memset(oct->instr_queue[0], 0, sizeof(struct octeon_instr_queue));
@@ -927,9 +927,9 @@ int octeon_setup_output_queues(struct octeon_device *oct)
 		desc_size = CFG_GET_DEF_RX_BUF_SIZE(CHIP_CONF(oct, cn23xx_vf));
 	}
 	oct->num_oqs = 0;
-	oct->droq[0] = vmalloc_node(sizeof(*oct->droq[0]), numa_node);
+	oct->droq[0] = vzalloc_node(sizeof(*oct->droq[0]), numa_node);
 	if (!oct->droq[0])
-		oct->droq[0] = vmalloc(sizeof(*oct->droq[0]));
+		oct->droq[0] = vzalloc(sizeof(*oct->droq[0]));
 	if (!oct->droq[0])
 		return 1;
 
-- 
1.8.3.1

Re: [PATCH net-next 0/3] LiquidIO: avoid VM low memory crashes

[Leon Romanovsky]

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On Wed, Jun 07, 2017 at 08:50:45PM -0700, Felix Manlunas wrote:
> From: Rick Farrington <ricardo.farrington@cavium.com>
>
> This patchset addresses issues brought about by low memory conditions
> in a VM.  These conditions were only seen when VM's were intentionally
> created with small amounts of memory (for stress testing).
>
> 1. Fix GPF in octeon_init_droq(); zero the allocated block 'recv_buf_list'.
>    This prevents a GPF trying to access an invalid 'recv_buf_list[i]' entry
>    in octeon_droq_destroy_ring_buffers() if init didn't alloc all entries.
> 2. Don't dereference a NULL ptr in octeon_droq_destroy_ring_buffers().
> 3. For defensive programming, zero the allocated block 'oct->droq[0]' in
>    octeon_setup_output_queues() and 'oct->instr_queue[0]' in
>    octeon_setup_instr_queues().
>

While these patches are harmless, I don't really understand how
allocating the same arrays just with zeros in it can prevent low memory
crashes. Once you used v[m,z]alloc, you should expect for failures in
these flows and relying on content of that page is not called "solve the
bug".

Thanks



>  drivers/net/ethernet/cavium/liquidio/octeon_device.c | 8 ++++----
>  drivers/net/ethernet/cavium/liquidio/octeon_droq.c   | 6 ++++--
>  2 files changed, 8 insertions(+), 6 deletions(-)
>
> --
> 1.8.3.1
>

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Re: [PATCH net-next 0/3] LiquidIO: avoid VM low memory crashes

[David Miller]

Please no "StudlyCaps" in the subject lines, the name of the driver
and the directory it is in is "liquidio" in all lower-case.

Thank you.