From: Dipayaan Roy <dipayanroy@linux.microsoft.com>
To: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org,
decui@microsoft.com, andrew+netdev@lunn.ch, davem@davemloft.net,
edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
leon@kernel.org, longli@microsoft.com, kotaranov@microsoft.com,
horms@kernel.org, shradhagupta@linux.microsoft.com,
ssengar@linux.microsoft.com, ernis@linux.microsoft.com,
shirazsaleem@microsoft.com, linux-hyperv@vger.kernel.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-rdma@vger.kernel.org, stephen@networkplumber.org,
jacob.e.keller@intel.com, dipayanroy@microsoft.com,
leitao@debian.org, kees@kernel.org, john.fastabend@gmail.com,
hawk@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net,
ast@kernel.org, sdf@fomichev.me, yury.norov@gmail.com
Subject: [PATCH net v2 1/2] net: mana: Add NULL guards in teardown path to prevent panic on attach failure
Date: Fri, 22 May 2026 16:33:12 -0700 [thread overview]
Message-ID: <20260522233555.1099342-2-dipayanroy@linux.microsoft.com> (raw)
In-Reply-To: <20260522233555.1099342-1-dipayanroy@linux.microsoft.com>
When queue allocation fails partway through, the error cleanup frees
and NULLs apc->tx_qp and apc->rxqs. Multiple teardown paths such as
mana_remove(), mana_change_mtu() recovery, and internal error handling
in mana_alloc_queues() can subsequently call into functions that
dereference these pointers without NULL checks:
- mana_chn_setxdp() dereferences apc->rxqs[0], causing a NULL pointer
dereference panic (CR2: 0000000000000000 at mana_chn_setxdp+0x26).
- mana_destroy_vport() iterates apc->rxqs without a NULL check.
- mana_fence_rqs() iterates apc->rxqs without a NULL check.
- mana_dealloc_queues() iterates apc->tx_qp without a NULL check.
Add NULL guards for apc->rxqs in mana_fence_rqs(),
mana_destroy_vport(), and before the mana_chn_setxdp() call. Add a
NULL guard for apc->tx_qp in mana_dealloc_queues() to skip TX queue
draining when TX queues were never allocated or already freed.
Fixes: ca9c54d2d6a5 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)")
Signed-off-by: Dipayaan Roy <dipayanroy@linux.microsoft.com>
---
drivers/net/ethernet/microsoft/mana/mana_en.c | 70 +++++++++++--------
1 file changed, 41 insertions(+), 29 deletions(-)
diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index 9afc786b297a..0582803907a8 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -1727,6 +1727,9 @@ static void mana_fence_rqs(struct mana_port_context *apc)
struct mana_rxq *rxq;
int err;
+ if (!apc->rxqs)
+ return;
+
for (rxq_idx = 0; rxq_idx < apc->num_queues; rxq_idx++) {
rxq = apc->rxqs[rxq_idx];
err = mana_fence_rq(apc, rxq);
@@ -2858,13 +2861,16 @@ static void mana_destroy_vport(struct mana_port_context *apc)
struct mana_rxq *rxq;
u32 rxq_idx;
- for (rxq_idx = 0; rxq_idx < apc->num_queues; rxq_idx++) {
- rxq = apc->rxqs[rxq_idx];
- if (!rxq)
- continue;
+ if (apc->rxqs) {
- mana_destroy_rxq(apc, rxq, true);
- apc->rxqs[rxq_idx] = NULL;
+ for (rxq_idx = 0; rxq_idx < apc->num_queues; rxq_idx++) {
+ rxq = apc->rxqs[rxq_idx];
+ if (!rxq)
+ continue;
+
+ mana_destroy_rxq(apc, rxq, true);
+ apc->rxqs[rxq_idx] = NULL;
+ }
}
mana_destroy_txq(apc);
@@ -3269,7 +3275,8 @@ static int mana_dealloc_queues(struct net_device *ndev)
if (apc->port_is_up)
return -EINVAL;
- mana_chn_setxdp(apc, NULL);
+ if (apc->rxqs)
+ mana_chn_setxdp(apc, NULL);
if (gd->gdma_context->is_pf && !apc->ac->bm_hostmode)
mana_pf_deregister_filter(apc);
@@ -3287,33 +3294,38 @@ static int mana_dealloc_queues(struct net_device *ndev)
* number of queues.
*/
- for (i = 0; i < apc->num_queues; i++) {
- txq = &apc->tx_qp[i].txq;
- tsleep = 1000;
- while (atomic_read(&txq->pending_sends) > 0 &&
- time_before(jiffies, timeout)) {
- usleep_range(tsleep, tsleep + 1000);
- tsleep <<= 1;
- }
- if (atomic_read(&txq->pending_sends)) {
- err = pcie_flr(to_pci_dev(gd->gdma_context->dev));
- if (err) {
- netdev_err(ndev, "flr failed %d with %d pkts pending in txq %u\n",
- err, atomic_read(&txq->pending_sends),
- txq->gdma_txq_id);
+ if (apc->tx_qp) {
+ for (i = 0; i < apc->num_queues; i++) {
+ txq = &apc->tx_qp[i].txq;
+ tsleep = 1000;
+ while (atomic_read(&txq->pending_sends) > 0 &&
+ time_before(jiffies, timeout)) {
+ usleep_range(tsleep, tsleep + 1000);
+ tsleep <<= 1;
+ }
+ if (atomic_read(&txq->pending_sends)) {
+ err =
+ pcie_flr(to_pci_dev(gd->gdma_context->dev));
+ if (err) {
+ netdev_err(ndev, "flr failed %d with %d pkts pending in txq %u\n",
+ err,
+ atomic_read(&txq->pending_sends),
+ txq->gdma_txq_id);
+ }
+ break;
}
- break;
}
- }
- for (i = 0; i < apc->num_queues; i++) {
- txq = &apc->tx_qp[i].txq;
- while ((skb = skb_dequeue(&txq->pending_skbs))) {
- mana_unmap_skb(skb, apc);
- dev_kfree_skb_any(skb);
+ for (i = 0; i < apc->num_queues; i++) {
+ txq = &apc->tx_qp[i].txq;
+ while ((skb = skb_dequeue(&txq->pending_skbs))) {
+ mana_unmap_skb(skb, apc);
+ dev_kfree_skb_any(skb);
+ }
+ atomic_set(&txq->pending_sends, 0);
}
- atomic_set(&txq->pending_sends, 0);
}
+
/* We're 100% sure the queues can no longer be woken up, because
* we're sure now mana_poll_tx_cq() can't be running.
*/
--
2.43.0
next prev parent reply other threads:[~2026-05-22 23:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-22 23:33 [PATCH net v2 0/2] net: mana: Fix NULL dereferences during teardown after attach failure Dipayaan Roy
2026-05-22 23:33 ` Dipayaan Roy [this message]
2026-05-25 8:01 ` [PATCH net v2 1/2] net: mana: Add NULL guards in teardown path to prevent panic on " Dipayaan Roy
2026-05-30 0:46 ` sashiko-bot
2026-05-22 23:33 ` [PATCH net v2 2/2] net: mana: Skip redundant detach on already-detached port Dipayaan Roy
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