[PATCH net 0/2] gve: Bug fixes for header-split and PTP

[PATCH net 0/2] gve: Bug fixes for header-split and PTP

[Harshitha Ramamurthy]

This series contains 2 bug fixes for gve.

Patch 1 fixes an issue which causes TX timeouts due to HW detection of
an illegal descriptor. This happens when receiving header-only packets
with header split enabled - this produces an SKB with a zero-length
fragment.

Patch 2 prevents a kernel NULL pointer dereference by stubbing the PTP
adjfine callback.

Jordan Rhee (2):
  gve: fix zero-length skb frag with header-split
  gve: fix NULL dereference due to missing ptp adjfine

 drivers/net/ethernet/google/gve/gve_ptp.c    | 6 ++++++
 drivers/net/ethernet/google/gve/gve_rx_dqo.c | 5 +++++
 2 files changed, 11 insertions(+)

-- 
2.55.0.679.g6767b8d81c-goog

[PATCH net 1/2] gve: fix zero-length skb frag with header-split

[Harshitha Ramamurthy]

From: Jordan Rhee <jordanrhee@google.com>

When header split is enabled and a header-only packet is
received such as a pure TCP ACK, GVE will indicate an
RX SKB with a zero-length fragment. If this SKB is then
hairpinned and sent back out, the GVE TX path will emit
a zero-length descriptor. Hardware considers this
an illegal descriptor and stops the queue, causing a
TX timeout and interface reset.

Fix it by not adding the zero-length skb frag.

Cc: stable@vger.kernel.org
Fixes: 5e37d8254e7f ("gve: Add header split data path")
Suggested-by: Praveen Kaligineedi <pkaligineedi@google.com>
Co-developed-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Jordan Rhee <jordanrhee@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
---
 drivers/net/ethernet/google/gve/gve_rx_dqo.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/google/gve/gve_rx_dqo.c b/drivers/net/ethernet/google/gve/gve_rx_dqo.c
index 8271f731a91f..0ece2f6fdffb 100644
--- a/drivers/net/ethernet/google/gve/gve_rx_dqo.c
+++ b/drivers/net/ethernet/google/gve/gve_rx_dqo.c
@@ -886,6 +886,11 @@ static int gve_rx_dqo(struct napi_struct *napi, struct gve_rx_ring *rx,
 		rx->rx_hsplit_unsplit_pkt += unsplit;
 		rx->rx_hsplit_bytes += hdr_len;
 		u64_stats_update_end(&rx->statss);
+
+		if (!buf_len) {
+			gve_free_buffer(rx, buf_state);
+			return 0;
+		}
 	} else if (!rx->ctx.skb_head && rx->dqo.page_pool &&
 		   netmem_is_net_iov(buf_state->page_info.netmem)) {
 		/* when header split is disabled, the header went to the packet
-- 
2.55.0.679.g6767b8d81c-goog

[PATCH net 2/2] gve: fix NULL dereference due to missing ptp adjfine

[Harshitha Ramamurthy]

From: Jordan Rhee <jordanrhee@google.com>

Fix NULL dereference due to missing implementation of adjfine, which can
be triggered from usermode as follows:

sudo ./testptp -d /dev/ptp0 -f 0
[  551.943697] BUG: kernel NULL pointer dereference, address: 0000000000000000
[...]
[  552.061946] Call Trace:
[  552.064487]  <TASK>
[  552.066681]  ptp_clock_adjtime+0x1c0/0x2c0
[  552.070874]  ? get_clock_desc+0x6b/0xb0
[  552.074825]  pc_clock_adjtime+0x78/0xc0
[  552.078755]  __do_sys_clock_adjtime+0x85/0x110
[  552.083293]  do_syscall_64+0xea/0x610

Cc: stable@vger.kernel.org
Fixes: acd16380523b ("gve: Add initial PTP device support")
Signed-off-by: Jordan Rhee <jordanrhee@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
---
 drivers/net/ethernet/google/gve/gve_ptp.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/google/gve/gve_ptp.c b/drivers/net/ethernet/google/gve/gve_ptp.c
index 06b1cf4a5efc..1d6c59f4ead3 100644
--- a/drivers/net/ethernet/google/gve/gve_ptp.c
+++ b/drivers/net/ethernet/google/gve/gve_ptp.c
@@ -26,6 +26,11 @@ int gve_clock_nic_ts_read(struct gve_priv *priv)
 	return 0;
 }
 
+static int gve_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
+{
+	return -EOPNOTSUPP;
+}
+
 static int gve_ptp_gettimex64(struct ptp_clock_info *info,
 			      struct timespec64 *ts,
 			      struct ptp_system_timestamp *sts)
@@ -60,6 +65,7 @@ static long gve_ptp_do_aux_work(struct ptp_clock_info *info)
 static const struct ptp_clock_info gve_ptp_caps = {
 	.owner          = THIS_MODULE,
 	.name		= "gve clock",
+	.adjfine	= gve_ptp_adjfine,
 	.gettimex64	= gve_ptp_gettimex64,
 	.settime64	= gve_ptp_settime64,
 	.do_aux_work	= gve_ptp_do_aux_work,
-- 
2.55.0.679.g6767b8d81c-goog

Re: [PATCH net 2/2] gve: fix NULL dereference due to missing ptp adjfine

[Vadim Fedorenko]

On 07/08/2026 23:43, Harshitha Ramamurthy wrote:
> From: Jordan Rhee <jordanrhee@google.com>
> 
> Fix NULL dereference due to missing implementation of adjfine, which can
> be triggered from usermode as follows:
> 
> sudo ./testptp -d /dev/ptp0 -f 0
> [  551.943697] BUG: kernel NULL pointer dereference, address: 0000000000000000
> [...]
> [  552.061946] Call Trace:
> [  552.064487]  <TASK>
> [  552.066681]  ptp_clock_adjtime+0x1c0/0x2c0
> [  552.070874]  ? get_clock_desc+0x6b/0xb0
> [  552.074825]  pc_clock_adjtime+0x78/0xc0
> [  552.078755]  __do_sys_clock_adjtime+0x85/0x110
> [  552.083293]  do_syscall_64+0xea/0x610
> 
> Cc: stable@vger.kernel.org
> Fixes: acd16380523b ("gve: Add initial PTP device support")
> Signed-off-by: Jordan Rhee <jordanrhee@google.com>
> Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
> ---
>   drivers/net/ethernet/google/gve/gve_ptp.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/net/ethernet/google/gve/gve_ptp.c b/drivers/net/ethernet/google/gve/gve_ptp.c
> index 06b1cf4a5efc..1d6c59f4ead3 100644
> --- a/drivers/net/ethernet/google/gve/gve_ptp.c
> +++ b/drivers/net/ethernet/google/gve/gve_ptp.c
> @@ -26,6 +26,11 @@ int gve_clock_nic_ts_read(struct gve_priv *priv)
>   	return 0;
>   }
>   
> +static int gve_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
>   static int gve_ptp_gettimex64(struct ptp_clock_info *info,
>   			      struct timespec64 *ts,
>   			      struct ptp_system_timestamp *sts)
> @@ -60,6 +65,7 @@ static long gve_ptp_do_aux_work(struct ptp_clock_info *info)
>   static const struct ptp_clock_info gve_ptp_caps = {
>   	.owner          = THIS_MODULE,
>   	.name		= "gve clock",
> +	.adjfine	= gve_ptp_adjfine,
>   	.gettimex64	= gve_ptp_gettimex64,
>   	.settime64	= gve_ptp_settime64,
>   	.do_aux_work	= gve_ptp_do_aux_work,

.adjtime has to be implemented as well - neither adjfine nor adjtime are
checked within ptp_clock_adjtime()