[PATCH net] net/mlx5e: Fix NULL deref in PTP TX timestamp recovery warn

[PATCH net] net/mlx5e: Fix NULL deref in PTP TX timestamp recovery warn

[Tariq Toukan]

From: Carolina Jubran <cjubran@nvidia.com>

PTP SQs are allocated via mlx5e_ptp_alloc_txqsq(), which never sets
sq->channel. The excessive port timestamp delta recovery path
incorrectly used sq->channel->netdev for netdev_warn(), causing a NULL
pointer dereference. Use sq->netdev instead.

Fixes: 391dad2e686f ("net/mlx5e: Recover SQ on excessive PTP TX timestamp delta")
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Alex Lazar <alazar@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
index 723f66a6bd63..2e1c3bb5a959 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
@@ -98,7 +98,7 @@ static void mlx5e_skb_cb_hwtstamp_tx(struct sk_buff *skb,
 		ptpsq->cq_stats->abort_abs_diff_ns += diff;
 		if (diff > (NSEC_PER_SEC >> 1) &&
 		    !test_and_set_bit(MLX5E_SQ_STATE_RECOVERING, &sq->state)) {
-			netdev_warn(sq->channel->netdev,
+			netdev_warn(sq->netdev,
 				    "PTP TX timestamp difference between CQE and port exceeds threshold: %lld ns, recovering SQ %u\n",
 				    (s64)diff, sq->sqn);
 			queue_work(sq->priv->wq, &ptpsq->report_unhealthy_work);

base-commit: 513444cc62e231a11c9b15ea88de0890da9b2b4f
-- 
2.44.0

Re: [PATCH net] net/mlx5e: Fix NULL deref in PTP TX timestamp recovery warn

[netdev-bot+sinfo]

Hi!

This is an automated message. This series looks like a fix, but its
commit messages seem to be missing some information:

 - How the issue was discovered, e.g. hit in production, hit during
   development, syzbot report, manual code inspection, LLM or static
   analysis tool scan.

 - Whether the issue was actually triggered, or is only theoretical
   (e.g. found by code inspection). If it was triggered please include
   the symptoms, like the stack trace or error messages.

Please do not repost the series just to address the above. Instead,
reply to this email with the missing information, so that reviewers
can take it into account. If the series needs another revision for
other reasons, please include the information in the commit messages
then.

The evaluation is done by an LLM so it may be wrong, if you think
that is the case please reply and explain.

Re: [PATCH net] net/mlx5e: Fix NULL deref in PTP TX timestamp recovery warn

[Carolina Jubran]

On 15/10/2026 11:09, netdev-bot+sinfo@kernel.org wrote:
> Hi!
>
> This is an automated message. This series looks like a fix, but its
> commit messages seem to be missing some information:
>
>   - How the issue was discovered, e.g. hit in production, hit during
>     development, syzbot report, manual code inspection, LLM or static
>     analysis tool scan.
>
>   - Whether the issue was actually triggered, or is only theoretical
>     (e.g. found by code inspection). If it was triggered please include
>     the symptoms, like the stack trace or error messages.
>
> Please do not repost the series just to address the above. Instead,
> reply to this email with the missing information, so that reviewers
> can take it into account. If the series needs another revision for
> other reasons, please include the information in the commit messages
> then.
>
> The evaluation is done by an LLM so it may be wrong, if you think
> that is the case please reply and explain.


Hi,

The issue was observed during our internal regression testing.

The kernel reported:

BUG: unable to handle page fault for address: 0000000000002ea8
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 1a9bfc067 P4D 1a9bfc067 PUD 1a9bfd067 PMD 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 0 Comm: swapper/0 Tainted: G           OE
RIP: 0010:mlx5e_skb_cb_hwtstamp_handler+0x10c/0x140 [mlx5_core]
RAX: 0000000000000000
CR2: 0000000000002ea8
Call Trace:
   mlx5e_ptp_poll_ts_cq+0x228/0x5b0 [mlx5_core]
   mlx5e_ptp_napi_poll+0xad/0x380 [mlx5_core]
   ? mlx5e_napi_poll+0x750/0x7e0 [mlx5_core]
   __napi_poll+0x30/0x200
   net_rx_action+0x181/0x2e0
   handle_softirqs+0xdb/0x340
   __irq_exit_rcu+0xd9/0x100
   irq_exit_rcu+0xe/0x20
   common_interrupt+0xa4/0xb0

So far, the issue has only been observed during our regression testing,
and I am still working on reproducing it reliably.

Thanks,
Carolina

Re: [PATCH net] net/mlx5e: Fix NULL deref in PTP TX timestamp recovery warn

[Kalesh Anakkur Purayil]

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On Thu, Oct 15, 2026 at 1:38 PM Tariq Toukan <tariqt@nvidia.com> wrote:

> From: Carolina Jubran <cjubran@nvidia.com>
>
> PTP SQs are allocated via mlx5e_ptp_alloc_txqsq(), which never sets
> sq->channel. The excessive port timestamp delta recovery path
> incorrectly used sq->channel->netdev for netdev_warn(), causing a NULL
> pointer dereference. Use sq->netdev instead.
>
> Fixes: 391dad2e686f ("net/mlx5e: Recover SQ on excessive PTP TX timestamp
> delta")
> Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
> Reviewed-by: Alex Lazar <alazar@nvidia.com>
> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
>
> LGTM,
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>


-- 
Regards,
Kalesh AP

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