[PATCH v4 net 0/4] net: hns3: fix multiple bugs in reset/error paths

[PATCH v4 net 0/4] net: hns3: fix multiple bugs in reset/error paths

[Jijie Shao]

This series contains four bug fixes for the HNS3 driver, all related
to resource lifecycle management on reset, driver unload, or error
paths.

Patch 1 fixes a vector resource leak in the error path of
hns3_nic_alloc_vector_data, where a devm_kcalloc failure after
successful get_vector() leaves allocated vectors unreleased.

Patch 2 fixes a page_pool leak in the error path of
hns3_alloc_ring_memory, where an hns3_alloc_ring_buffers() failure
for an RX ring frees the descriptor ring but not the page_pool
allocated just before.

Patch 3 fixes an interface stall that occurs when the hardware RX
queue is full and memory allocation fails.  Without an RX interrupt,
NAPI is never scheduled and the queue cannot drain.  A delayed work
re-arms NAPI polling on affected rings to break the deadlock.

Patch 4 fixes a use-after-free in debugfs read callbacks that can
access priv->ring and ring->desc while reset, driver unload, or
ethtool ring resize is freeing those resources.  A mutex is added
to synchronize debugfs readers against resource teardown.

---
Changes in v4:
  - Patch 1: correct the reason for resetting priv->vector_num, as
    reported by Sashiko.  hns3_nic_dealloc_vector_data() is not
    reachable after hns3_nic_alloc_vector_data() fails, so the reset
    is not protecting that path; it keeps the count from describing
    vectors that were already handed back.
  - Patch 2: name hns3_fini_ring() instead of the non-existent
    hns3_free_ring_memory(), and drop "mirroring" because the destroy
    order differs.  The pool is destroyed before the descriptor ring
    here, which is safe because hns3_alloc_ring_buffers() has already
    detached every buffer.
  - Patch 3:
    * Allocate rx_ring_oom_bm in hns3_init_all_ring() only after every
      ring has been set up, and free it in hns3_uninit_all_ring().
      This fixes the leak and the NULL bitmap dereference reported for
      hns3_set_ringparam(), which calls hns3_init_all_ring() without a
      matching hns3_uninit_all_ring(); the allocation is reused when
      the pointer is already set.
    * Cancel the delayed work in hns3_nic_uninit_vector_data() instead
      of hns3_nic_net_down(), so every teardown path cancels it before
      the bitmap is freed.  This closes the use-after-free reported
      for the self-test and external loopback paths, which set DOWN
      without going through hns3_nic_net_down().
    * Drop the cancel and bitmap_zero from hns3_nic_net_down().  A
      pending work that runs while DOWN is set zeroes the bitmap and
      exits, and one that runs after the interface is brought back up
      only schedules a single extra poll round.
    * Always attempt the exit refill in hns3_clean_rx_ring(), so the
      descriptors cleaned by this poll stay armed and the head pointer
      is written as before.
    * Document why rx_oom_cnt is not the standard rx-alloc-fail
      counter, as requested in review.
  - Patch 4: describe both writer paths (client_uninit/reset_uninit vs
    set_ringparam) explicitly, note the -EBUSY user-visible change, and
    return -EBUSY from hns3_dbg_page_pool_info() instead of -EFAULT so
    that sibling readers agree.
v3: https://lore.kernel.org/all/20261030095633.377289-1-shaojijie@huawei.com/
Changes in v3:
  - Patch 1: simplify commit message; drop the accumulated-leak
    consequence paragraph and clarify that the vector_num reset avoids
    a NULL deref in hns3_nic_dealloc_vector_data().
  - Patch 2: new patch, fixes a page_pool leak in the error path of
    hns3_alloc_ring_memory().
  - Patch 3: rework the OOM bitmap from per-vector to per-ring,
    indexed by ring->queue_index.  Add cancel_delayed_work_sync() in
    hns3_nic_net_down() after hns3_disable_irqs_and_tqps().  Remove
    the OOM marking in hns3_handle_rx_copybreak() since the packet is
    still delivered via the original page.
  - Patch 4: add Fixes tag for the ring resize path.  Add per-ring
    page_pool NULL check at hns3_dump_page_pool_info() entry.
v2: https://lore.kernel.org/all/20261021121426.3096838-1-shaojijie@huawei.com/
Changes in v2:
Patch 1:
  - No change.
Patch 2:
  - Clear per-vector OOM bitmap when device is DOWN to avoid
    spurious napi_schedule() on next up event.
  - Move rx_oom_cnt accounting to hns3_ring_set_oom_state() with
    test_and_set_bit() for per-event counting.
Patch 3:
  - Drop hclge_debugfs.c changes; mutex only protects enet-layer.
  - Replace guard(mutex) with explicit mutex_lock/unlock.
  - Remove redundant NULL checks; unify -EPERM to -EBUSY.
v1: https://lore.kernel.org/all/20260915132434.1141742-1-shaojijie@huawei.com/
---

Jijie Shao (4):
  net: hns3: fix vector resource leak in hns3_nic_alloc_vector_data
  net: hns3: fix page_pool leak in hns3_alloc_ring_memory error path
  net: hns3: fix interface stuck after OOM with full hardware rx queue
  net: hns3: fix use-after-free in debugfs read during reset/unload

 drivers/net/ethernet/hisilicon/hns3/hnae3.h   |   1 +
 .../ethernet/hisilicon/hns3/hns3_debugfs.c    | 127 +++++++++++-------
 .../net/ethernet/hisilicon/hns3/hns3_enet.c   |  80 ++++++++++-
 .../net/ethernet/hisilicon/hns3/hns3_enet.h   |  18 +++
 .../ethernet/hisilicon/hns3/hns3_ethtool.c    |   3 +
 5 files changed, 179 insertions(+), 50 deletions(-)


base-commit: 8d5ce4751fad9499ea408163af7f410f18a85782
-- 
2.43.0

[PATCH v4 net 1/4] net: hns3: fix vector resource leak in hns3_nic_alloc_vector_data

[Jijie Shao]

When devm_kcalloc() fails for priv->tqp_vector after get_vector() has
already acquired MSI-X vectors, the error path returns without calling
put_vector() to release them, leaving the hclge/hclgevf bookkeeping
(num_msi_used, num_msi_left, vector_status[]) inconsistent.

Call put_vector() for every acquired vector before returning the error,
and reset priv->vector_num to 0 so the count never describes vectors
that were already handed back.

Fixes: dd38c72604dc ("net: hns3: fix for coalesce configuration lost during reset")
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
---
Changes in v4:
  - Correct the reason for resetting priv->vector_num.  Sashiko pointed
    out that hns3_nic_dealloc_vector_data() is not reachable after
    hns3_nic_alloc_vector_data() fails, so the reset is not protecting
    that path; it keeps the count from describing vectors that were
    already handed back.
v3: https://lore.kernel.org/all/20261030095633.377289-2-shaojijie@huawei.com/
Changes in v3:
  - Simplify commit message: drop the accumulated-leak consequence
    paragraph and clarify that the vector_num reset avoids a NULL
    deref in hns3_nic_dealloc_vector_data().
v2: https://lore.kernel.org/all/20261021121426.3096838-2-shaojijie@huawei.com/
---
 drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 47788be64be6..2f3aeade558c 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -4854,7 +4854,7 @@ static int hns3_nic_alloc_vector_data(struct hns3_nic_priv *priv)
 			     GFP_KERNEL);
 	if (!priv->tqp_vector) {
 		ret = -ENOMEM;
-		goto out;
+		goto err_put_vector;
 	}
 
 	for (i = 0; i < priv->vector_num; i++) {
@@ -4865,7 +4865,13 @@ static int hns3_nic_alloc_vector_data(struct hns3_nic_priv *priv)
 		hns3_vector_coalesce_init(tqp_vector, priv);
 	}
 
-out:
+	devm_kfree(&pdev->dev, vector);
+	return 0;
+
+err_put_vector:
+	for (i = 0; i < vector_num; i++)
+		h->ae_algo->ops->put_vector(h, vector[i].vector);
+	priv->vector_num = 0;
 	devm_kfree(&pdev->dev, vector);
 	return ret;
 }
-- 
2.43.0

[PATCH v4 net 2/4] net: hns3: fix page_pool leak in hns3_alloc_ring_memory error path

[Jijie Shao]

In hns3_alloc_ring_memory(), when hns3_alloc_ring_buffers() fails for
an RX ring, the error path jumps to out_with_desc, which frees the
descriptor ring but does not destroy the page_pool that was just
allocated by hns3_alloc_page_pool(). The page_pool and its pages are
leaked.

Destroy the page_pool in that error path as well. The pool is torn down
before the descriptor ring here, which is the opposite of the order in
hns3_fini_ring(); that is safe because hns3_alloc_ring_buffers() has
already detached every buffer it attached, so hns3_free_desc() walks
descriptors whose dma is zero and never hands a page back to the pool.

Fixes: 93188e9642c3 ("net: hns3: support skb's frag page recycling based on page pool")
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
---
Changes in v4:
  - Name hns3_fini_ring() instead of the non-existent
    hns3_free_ring_memory(), and drop "mirroring" because the destroy
    order differs.  The pool is destroyed before the descriptor ring
    here, which is safe because hns3_alloc_ring_buffers() has already
    detached every buffer.
v3: https://lore.kernel.org/all/20261030095633.377289-3-shaojijie@huawei.com/
---
 drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 2f3aeade558c..dbf32c00bb7f 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -5078,6 +5078,8 @@ static int hns3_alloc_ring_memory(struct hns3_enet_ring *ring)
 	return 0;
 
 out_with_desc:
+	page_pool_destroy(ring->page_pool);
+	ring->page_pool = NULL;
 	hns3_free_desc(ring);
 out_with_desc_cb:
 	devm_kfree(ring_to_dev(ring), ring->desc_cb);
-- 
2.43.0

[PATCH v4 net 3/4] net: hns3: fix interface stuck after OOM with full hardware rx queue

[Jijie Shao]

NAPI polling on hns3 is driven by hardware RX interrupts. Under
memory pressure, RX skb and frag allocations fail, packets are no
longer reaped from the hardware rx ring. Once the ring fills, the
hardware stops generating RX interrupts and NAPI is never scheduled
again -- even after memory becomes available, leaving the interface
deadlocked.

Break the deadlock by adding a software recovery path that re-arms
NAPI via a 250ms delayed_work, independent of hardware interrupts.
A per-ring bitmap tracks which RX rings are in OOM state; the work
function schedules NAPI for the vector backing each affected ring.
OOM state is marked at every RX allocation failure site and cleared
when the delayed_work fires.

This supersedes the busy-poll recovery from commit 68752b24f51a
("net: hns3: schedule the polling again when allocation fails"),
which returned budget on allocation failure to keep NAPI polling
and caused CPU spinning under prolonged memory pressure. Now
hns3_clean_rx_ring() returns recv_pkts instead of budget on
allocation failure, letting NAPI exit and the delayed_work take
over. The exit refill is still attempted, so the descriptors cleaned
by this poll stay armed. Add rx_oom_cnt ethtool counter, incremented
once per OOM event (on the 0 -> 1 bitmap transition) for diagnostics.
It counts OOM episodes rather than individual allocation failures,
so it is not the standard rx-alloc-fail counter.

The bitmap is allocated in hns3_init_all_ring() and freed in
hns3_uninit_all_ring(). It is allocated after every ring is set up,
so a failure inside hns3_init_all_ring() leaves nothing behind, and
it is reused because hns3_set_ringparam() calls hns3_init_all_ring()
without hns3_uninit_all_ring(). The delayed_work is cancelled in
hns3_nic_uninit_vector_data(), which every teardown path reaches
before the bitmap is freed.

hns3_nic_net_down() does not cancel the work, so a pending work may
still run after the interface goes down. If it runs while DOWN is
set, it zeroes the bitmap and returns without scheduling NAPI. If
the interface is brought back up within the 250ms window, it sees
the stale bits with DOWN cleared and schedules NAPI for those rings
once, ending in a single extra poll round with no packet to clean.
Both outcomes are harmless.

Fixes: 68752b24f51a ("net: hns3: schedule the polling again when allocation fails")
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
---
Changes in v4:
  - Allocate rx_ring_oom_bm in hns3_init_all_ring() only after every
    ring has been set up, and free it in hns3_uninit_all_ring().  This
    fixes the leak and the NULL bitmap dereference in the
    hns3_set_ringparam() path, which calls hns3_init_all_ring()
    without a matching hns3_uninit_all_ring(), and reuses the existing
    allocation on a ring resize.
  - Cancel the delayed work in hns3_nic_uninit_vector_data() instead
    of hns3_nic_net_down(), so every teardown path cancels it before
    the bitmap is freed.  The self-test and external loopback paths
    set DOWN without going through hns3_nic_net_down().
  - Drop the cancel and bitmap_zero from hns3_nic_net_down().  A
    pending work that runs while DOWN is set zeroes the bitmap and
    exits, and one that runs after the interface is brought back up
    only schedules a single extra poll round.
  - Always attempt the exit refill in hns3_clean_rx_ring(), so the
    descriptors cleaned by this poll stay armed and the head pointer
    is written as before.
  - Document why rx_oom_cnt is not the standard rx-alloc-fail counter.
v3: https://lore.kernel.org/all/20261030095633.377289-4-shaojijie@huawei.com/
Changes in v3:
  - Rework the OOM bitmap from per-vector to per-ring, indexed by
    ring->queue_index, so each ring's OOM event is counted exactly
    once per oom_task firing cycle regardless of vector sharing.
  - Add cancel_delayed_work_sync(&priv->oom_task) to
    hns3_nic_net_down(), placed after hns3_disable_irqs_and_tqps(),
    eliminating the stop/open window where a preempted worker could
    clear a bit newly set by NAPI on the reopened interface.
  - Remove the hns3_ring_set_oom_state() call from
    hns3_handle_rx_copybreak(): napi_alloc_frag() failure returns
    -ENOMEM but the packet is still delivered via the original page,
    so it should not drive the OOM recovery work.
v2: https://lore.kernel.org/all/20261021121426.3096838-3-shaojijie@huawei.com/
Changes in v2:
  - Clear per-vector OOM bitmap when device is DOWN to avoid
    spurious napi_schedule() on next up event.
  - Move rx_oom_cnt accounting to hns3_ring_set_oom_state() with
    test_and_set_bit() for per-event counting.
  - Expand changelog: reference commit 68752b24f51a, explain
    hns3_clean_rx_ring() return value change, document rx_oom_cnt
    per-event counting semantics.
v1: https://lore.kernel.org/all/20260915132434.1141742-3-shaojijie@huawei.com/
---
 .../net/ethernet/hisilicon/hns3/hns3_enet.c   | 61 ++++++++++++++++++-
 .../net/ethernet/hisilicon/hns3/hns3_enet.h   | 18 ++++++
 .../ethernet/hisilicon/hns3/hns3_ethtool.c    |  1 +
 3 files changed, 77 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index dbf32c00bb7f..90f0a8ac9295 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -78,6 +78,8 @@ module_param(page_pool_enabled, bool, 0400);
 #define HNS3_MIN_TX_LEN		33U
 #define HNS3_MIN_TUN_PKT_LEN	65U
 
+#define HNS3_OOM_POLL_INTERVAL_MS	250
+
 /* hns3_pci_tbl - PCI Device ID Table
  *
  * Last entry must be all 0s
@@ -4162,6 +4164,7 @@ static int hns3_add_frag(struct hns3_enet_ring *ring)
 			if (unlikely(!new_skb)) {
 				hns3_rl_err(ring_to_netdev(ring),
 					    "alloc rx fraglist skb fail\n");
+				hns3_ring_set_oom_state(ring);
 				return -ENXIO;
 			}
 
@@ -4451,6 +4454,35 @@ static int hns3_handle_rx_bd(struct hns3_enet_ring *ring)
 	return 0;
 }
 
+static void hns3_oom_task(struct work_struct *work)
+{
+	struct hns3_nic_priv *priv = container_of(work, struct hns3_nic_priv,
+						  oom_task.work);
+	struct hnae3_handle *h = priv->ae_handle;
+	struct hns3_enet_ring *ring;
+	u16 i;
+
+	if (test_bit(HNS3_NIC_STATE_DOWN, &priv->state)) {
+		bitmap_zero(priv->rx_ring_oom_bm, h->kinfo.num_tqps);
+		return;
+	}
+
+	for (i = 0; i < h->kinfo.num_tqps; i++)
+		if (test_and_clear_bit(i, priv->rx_ring_oom_bm)) {
+			ring = &priv->ring[i + h->kinfo.num_tqps];
+			napi_schedule(&ring->tqp_vector->napi);
+		}
+}
+
+static void hns3_oom_task_schedule(struct hns3_enet_ring *ring)
+{
+	struct hns3_nic_priv *priv = netdev_priv(ring_to_netdev(ring));
+
+	hns3_ring_set_oom_state(ring);
+	schedule_delayed_work(&priv->oom_task,
+			      msecs_to_jiffies(HNS3_OOM_POLL_INTERVAL_MS));
+}
+
 int hns3_clean_rx_ring(struct hns3_enet_ring *ring, int budget,
 		       void (*rx_fn)(struct hns3_enet_ring *, struct sk_buff *))
 {
@@ -4472,6 +4504,9 @@ int hns3_clean_rx_ring(struct hns3_enet_ring *ring, int budget,
 
 		/* Poll one pkt */
 		err = hns3_handle_rx_bd(ring);
+		if (unlikely(err == -ENOMEM))
+			failure = true;
+
 		/* Do not get FE for the packet or failed to alloc skb */
 		if (unlikely(!ring->skb || err == -ENXIO)) {
 			goto out;
@@ -4490,10 +4525,12 @@ int hns3_clean_rx_ring(struct hns3_enet_ring *ring, int budget,
 	 * FBD number with head pointer
 	 */
 	if (unused_count > 0)
-		failure = failure ||
-			  hns3_nic_alloc_rx_buffers(ring, unused_count);
+		failure |= hns3_nic_alloc_rx_buffers(ring, unused_count);
 
-	return failure ? budget : recv_pkts;
+	if (unlikely(failure || hns3_ring_is_oom_state(ring)))
+		hns3_oom_task_schedule(ring);
+
+	return recv_pkts;
 }
 
 static void hns3_update_rx_int_coalesce(struct hns3_enet_tqp_vector *tqp_vector)
@@ -4788,6 +4825,7 @@ static int hns3_nic_init_vector_data(struct hns3_nic_priv *priv)
 			       hns3_nic_common_poll);
 	}
 
+	INIT_DELAYED_WORK(&priv->oom_task, hns3_oom_task);
 	return 0;
 
 map_ring_fail:
@@ -4889,6 +4927,8 @@ static void hns3_nic_uninit_vector_data(struct hns3_nic_priv *priv)
 	struct hns3_enet_tqp_vector *tqp_vector;
 	int i;
 
+	cancel_delayed_work_sync(&priv->oom_task);
+
 	for (i = 0; i < priv->vector_num; i++) {
 		tqp_vector = &priv->tqp_vector[i];
 
@@ -5204,6 +5244,16 @@ int hns3_init_all_ring(struct hns3_nic_priv *priv)
 		cond_resched();
 	}
 
+	/* hns3_set_ringparam() calls this without hns3_uninit_all_ring(). */
+	if (!priv->rx_ring_oom_bm) {
+		priv->rx_ring_oom_bm = bitmap_zalloc(h->kinfo.num_tqps,
+						     GFP_KERNEL);
+		if (!priv->rx_ring_oom_bm) {
+			ret = -ENOMEM;
+			goto out_when_alloc_ring_memory;
+		}
+	}
+
 	return 0;
 
 out_when_alloc_ring_memory:
@@ -5222,6 +5272,11 @@ static void hns3_uninit_all_ring(struct hns3_nic_priv *priv)
 		hns3_fini_ring(&priv->ring[i]);
 		hns3_fini_ring(&priv->ring[i + h->kinfo.num_tqps]);
 	}
+
+	if (priv->rx_ring_oom_bm) {
+		bitmap_free(priv->rx_ring_oom_bm);
+		priv->rx_ring_oom_bm = NULL;
+	}
 }
 
 /* Set mac addr if it is configured. or leave it to the AE driver */
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
index 933e3527ed82..5470df5d8efb 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
@@ -449,6 +449,7 @@ struct ring_stats {
 			u64 non_reuse_pg;
 			u64 frag_alloc_err;
 			u64 frag_alloc;
+			u64 rx_oom_cnt;
 		};
 		__le16 csum;
 	};
@@ -585,6 +586,8 @@ struct hns3_nic_priv {
 	struct hns3_enet_tqp_vector *tqp_vector;
 	u16 vector_num;
 	u8 max_non_tso_bd_num;
+	struct delayed_work oom_task;
+	unsigned long *rx_ring_oom_bm;
 
 	u64 tx_timeout_count;
 
@@ -711,6 +714,21 @@ static inline unsigned int hns3_page_order(struct hns3_enet_ring *ring)
 #define hns3_rl_usec_to_reg(int_rl) ((int_rl) >> 2)
 #define hns3_rl_round_down(int_rl) round_down(int_rl, 4)
 
+static inline void hns3_ring_set_oom_state(struct hns3_enet_ring *ring)
+{
+	struct hns3_nic_priv *priv = netdev_priv(ring_to_netdev(ring));
+
+	if (!test_and_set_bit(ring->queue_index, priv->rx_ring_oom_bm))
+		hns3_ring_stats_update(ring, rx_oom_cnt);
+}
+
+static inline bool hns3_ring_is_oom_state(struct hns3_enet_ring *ring)
+{
+	struct hns3_nic_priv *priv = netdev_priv(ring_to_netdev(ring));
+
+	return test_bit(ring->queue_index, priv->rx_ring_oom_bm);
+}
+
 void hns3_ethtool_set_ops(struct net_device *netdev);
 int hns3_set_channels(struct net_device *netdev,
 		      struct ethtool_channels *ch);
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
index 7b92a3c73ef6..14642f81efe1 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
@@ -62,6 +62,7 @@ static const struct hns3_stats hns3_rxq_stats[] = {
 	HNS3_TQP_STAT("non_reuse_pg", non_reuse_pg),
 	HNS3_TQP_STAT("frag_alloc_err", frag_alloc_err),
 	HNS3_TQP_STAT("frag_alloc", frag_alloc),
+	HNS3_TQP_STAT("rx_oom_cnt", rx_oom_cnt),
 };
 
 #define HNS3_PRIV_FLAGS_LEN ARRAY_SIZE(hns3_priv_flags)
-- 
2.43.0

[PATCH v4 net 4/4] net: hns3: fix use-after-free in debugfs read during reset/unload

[Jijie Shao]

The seq_file refactoring of hns3 debugfs removed the per-file entry
state checks. Without them, debugfs show callbacks can access
priv->ring, priv->tqp_vector, and ring->desc while these resources
are being freed by reset, driver unload, or ethtool ring resize.

Plain state-bit checks leave a TOCTOU window between check and use.

Fix by adding a mutex (dbg_mutex) to struct hnae3_handle, used by
enet-layer debugfs callbacks. Readers acquire the mutex, then check
device state per iteration -- this lets an in-flight reader exit
promptly when reset begins mid-dump, keeping reset latency bounded
by one iteration, and also rejects a reader that arrives after the
writer has finished tearing down resources (priv->ring is NULL by
then). The dbg_uninit() call stays outside the mutex to avoid
deadlock with debugfs_remove_recursive().

Two kinds of writer paths are protected:

  * hns3_client_uninit() and hns3_reset_notify_uninit_enet() clear
    HNS3_NIC_STATE_INITED first so that readers running outside the
    mutex see the device as busy and return -EBUSY early, then take
    dbg_mutex before freeing resources.

  * hns3_set_ringparam() calls ndo_stop() first (which sets
    HNS3_NIC_STATE_DOWN) and then takes dbg_mutex around the ring
    re-allocation. The busy check does not test the DOWN bit, so
    readers that arrive here are blocked by the mutex itself rather
    than by the INITED signal.

Userspace-visible change: debugfs reads under
/sys/kernel/debug/hns3/*/ that race with reset, driver unload, or
ethtool ring resize now return -EBUSY instead of potentially reading
freed or zero-filled memory.

Fixes: a723fb8efe29d3 ("net: hns3: refine for set ring parameters")
Fixes: eced3d1c41db ("net: hns3: use seq_file for files in queue/ in debugfs")
Closes: https://lore.kernel.org/all/a0853cd9-cab5-441d-b181-8ba97f2f58b0@huawei.com/
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
---
Changes in v4:
  - Describe both writer paths (client_uninit/reset_uninit vs
    set_ringparam) explicitly and note the -EBUSY user-visible change.
  - Return -EBUSY from hns3_dbg_page_pool_info() instead of -EFAULT
    when priv->ring is NULL, matching the sibling readers.
v3: https://lore.kernel.org/all/20261030095633.377289-5-shaojijie@huawei.com/
Changes in v3:
  - Add Fixes tag for a723fb8efe29d3 ("net: hns3: refine for set ring
    parameters"): the ring resize path it introduced is the writer that
    can free and rebuild rings, which is the root cause of the UAF
    window exposed by the seq_file refactoring.
  - Add per-ring page_pool NULL check at the entry of
    hns3_dump_page_pool_info(), avoiding a NULL deref while holding
    dbg_mutex (which would deadlock reset on the mutex).
v2: https://lore.kernel.org/all/20261021121426.3096838-4-shaojijie@huawei.com/
Changes in v2:
  - Drop hclge_debugfs.c changes; mutex only protects enet-layer
    debugfs callbacks.
  - Replace guard(mutex) with explicit mutex_lock/unlock and
    "goto unlock" error-path labels.
  - Remove redundant if (!priv->ring) checks in
    hns3_dbg_rx_queue_info() and hns3_dbg_tx_queue_info().
  - Unify per-iteration return values from -EPERM to -EBUSY.
  - Reorder local variables to reverse-Christmas-tree order.
  - Reword changelog to drop the "PF-layer" description.
v1: https://lore.kernel.org/all/20260915132434.1141742-4-shaojijie@huawei.com/
---
 drivers/net/ethernet/hisilicon/hns3/hnae3.h   |   1 +
 .../ethernet/hisilicon/hns3/hns3_debugfs.c    | 127 +++++++++++-------
 .../net/ethernet/hisilicon/hns3/hns3_enet.c   |   7 +
 .../ethernet/hisilicon/hns3/hns3_ethtool.c    |   2 +
 4 files changed, 92 insertions(+), 45 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hnae3.h b/drivers/net/ethernet/hisilicon/hns3/hnae3.h
index 4286af9239b0..e94cc33da864 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hnae3.h
+++ b/drivers/net/ethernet/hisilicon/hns3/hnae3.h
@@ -944,6 +944,7 @@ struct hnae3_handle {
 
 	u8 netdev_flags;
 	struct dentry *hnae3_dbgfs;
+	struct mutex dbg_mutex;	/* protect debugfs against reset/unload */
 
 	/* Network interface message level enabled bits */
 	u32 msg_enable;
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
index 1347edac7699..a58ca42dbcd9 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
@@ -389,6 +389,12 @@ static const char * const dim_state_str[] = { "START", "IN_PROG", "APPLY" };
 static const char * const
 dim_tune_stat_str[] = { "ON_TOP", "TIRED", "RIGHT", "LEFT" };
 
+static bool hns3_dbg_is_device_busy(struct hns3_nic_priv *priv)
+{
+	return !test_bit(HNS3_NIC_STATE_INITED, &priv->state) ||
+	       test_bit(HNS3_NIC_STATE_RESETTING, &priv->state);
+}
+
 static void hns3_get_coal_info(struct hns3_enet_tqp_vector *tqp_vector,
 			       struct seq_file *s, int i, bool is_tx)
 {
@@ -434,7 +440,7 @@ static void hns3_get_coal_info(struct hns3_enet_tqp_vector *tqp_vector,
 	}
 }
 
-static void hns3_dump_coal_info(struct seq_file *s, bool is_tx)
+static int hns3_dump_coal_info(struct seq_file *s, bool is_tx)
 {
 	struct hnae3_handle *h = hnae3_seq_file_to_handle(s);
 	struct hns3_enet_tqp_vector *tqp_vector;
@@ -448,18 +454,34 @@ static void hns3_dump_coal_info(struct seq_file *s, bool is_tx)
 	seq_puts(s, "HW_GL  HW_QL\n");
 
 	for (i = 0; i < priv->vector_num; i++) {
+		/* Per-iteration check bounds reset latency to one iteration. */
+		if (hns3_dbg_is_device_busy(priv))
+			return -EBUSY;
+
 		tqp_vector = &priv->tqp_vector[i];
 		hns3_get_coal_info(tqp_vector, s, i, is_tx);
 	}
+
+	return 0;
 }
 
 static int hns3_dbg_coal_info(struct seq_file *s, void *data)
 {
-	hns3_dump_coal_info(s, true);
+	struct hnae3_handle *h = hnae3_seq_file_to_handle(s);
+	struct hns3_nic_priv *priv = h->priv;
+	int ret;
+
+	mutex_lock(&priv->ae_handle->dbg_mutex);
+	ret = hns3_dump_coal_info(s, true);
+	if (ret)
+		goto unlock;
+
 	seq_puts(s, "\n");
-	hns3_dump_coal_info(s, false);
+	ret = hns3_dump_coal_info(s, false);
 
-	return 0;
+unlock:
+	mutex_unlock(&priv->ae_handle->dbg_mutex);
+	return ret;
 }
 
 static void hns3_dump_rx_queue_info(struct hns3_enet_ring *ring,
@@ -504,27 +526,22 @@ static int hns3_dbg_rx_queue_info(struct seq_file *s, void *data)
 	struct hns3_enet_ring *ring;
 	u32 i;
 
-	if (!priv->ring) {
-		dev_err(&h->pdev->dev, "priv->ring is NULL\n");
-		return -EFAULT;
-	}
-
+	mutex_lock(&priv->ae_handle->dbg_mutex);
 	seq_puts(s, "QUEUE_ID  BD_NUM  BD_LEN  TAIL  HEAD  FBDNUM  ");
 	seq_puts(s, "PKTNUM     COPYBREAK  RING_EN  RX_RING_EN  BASE_ADDR\n");
 
 	for (i = 0; i < h->kinfo.num_tqps; i++) {
-		/* Each cycle needs to determine whether the instance is reset,
-		 * to prevent reference to invalid memory. And need to ensure
-		 * that the following code is executed within 100ms.
-		 */
-		if (!test_bit(HNS3_NIC_STATE_INITED, &priv->state) ||
-		    test_bit(HNS3_NIC_STATE_RESETTING, &priv->state))
-			return -EPERM;
+		/* Per-iteration check bounds reset latency to one iteration. */
+		if (hns3_dbg_is_device_busy(priv)) {
+			mutex_unlock(&priv->ae_handle->dbg_mutex);
+			return -EBUSY;
+		}
 
 		ring = &priv->ring[(u32)(i + h->kinfo.num_tqps)];
 		hns3_dump_rx_queue_info(ring, s, i);
 	}
 
+	mutex_unlock(&priv->ae_handle->dbg_mutex);
 	return 0;
 }
 
@@ -569,27 +586,22 @@ static int hns3_dbg_tx_queue_info(struct seq_file *s, void *data)
 	struct hns3_enet_ring *ring;
 	u32 i;
 
-	if (!priv->ring) {
-		dev_err(&h->pdev->dev, "priv->ring is NULL\n");
-		return -EFAULT;
-	}
-
+	mutex_lock(&priv->ae_handle->dbg_mutex);
 	seq_puts(s, "QUEUE_ID  BD_NUM  TC  TAIL  HEAD  FBDNUM  OFFSET  ");
 	seq_puts(s, "PKTNUM     RING_EN  TX_RING_EN  BASE_ADDR\n");
 
 	for (i = 0; i < h->kinfo.num_tqps; i++) {
-		/* Each cycle needs to determine whether the instance is reset,
-		 * to prevent reference to invalid memory. And need to ensure
-		 * that the following code is executed within 100ms.
-		 */
-		if (!test_bit(HNS3_NIC_STATE_INITED, &priv->state) ||
-		    test_bit(HNS3_NIC_STATE_RESETTING, &priv->state))
-			return -EPERM;
+		/* Per-iteration check bounds reset latency to one iteration. */
+		if (hns3_dbg_is_device_busy(priv)) {
+			mutex_unlock(&priv->ae_handle->dbg_mutex);
+			return -EBUSY;
+		}
 
 		ring = &priv->ring[i];
 		hns3_dump_tx_queue_info(ring, s, i);
 	}
 
+	mutex_unlock(&priv->ae_handle->dbg_mutex);
 	return 0;
 }
 
@@ -604,14 +616,23 @@ static int hns3_dbg_queue_map(struct seq_file *s, void *data)
 
 	seq_puts(s, "local_queue_id  global_queue_id  vector_id\n");
 
+	mutex_lock(&priv->ae_handle->dbg_mutex);
 	for (i = 0; i < h->kinfo.num_tqps; i++) {
+		/* Per-iteration check bounds reset latency to one iteration. */
+		if (hns3_dbg_is_device_busy(priv)) {
+			mutex_unlock(&priv->ae_handle->dbg_mutex);
+			return -EBUSY;
+		}
+
 		if (!priv->ring || !priv->ring[i].tqp_vector)
 			continue;
+
 		seq_printf(s, "%-16u%-17u%d\n", i,
 			   h->ae_algo->ops->get_global_queue_id(h, i),
 			   priv->ring[i].tqp_vector->vector_irq);
 	}
 
+	mutex_unlock(&priv->ae_handle->dbg_mutex);
 	return 0;
 }
 
@@ -661,8 +682,11 @@ static int hns3_dbg_rx_bd_info(struct seq_file *s, void *private)
 
 	ring = &priv->ring[data->qid + data->handle->kinfo.num_tqps];
 	for (i = 0; i < ring->desc_num; i++) {
-		desc = &ring->desc[i];
+		/* Per-iteration check bounds reset latency to one iteration. */
+		if (hns3_dbg_is_device_busy(priv))
+			return -EBUSY;
 
+		desc = &ring->desc[i];
 		hns3_dump_rx_bd_info(priv, desc, s, i);
 	}
 
@@ -706,8 +730,11 @@ static int hns3_dbg_tx_bd_info(struct seq_file *s, void *private)
 
 	ring = &priv->ring[data->qid];
 	for (i = 0; i < ring->desc_num; i++) {
-		desc = &ring->desc[i];
+		/* Per-iteration check bounds reset latency to one iteration. */
+		if (hns3_dbg_is_device_busy(priv))
+			return -EBUSY;
 
+		desc = &ring->desc[i];
 		hns3_dump_tx_bd_info(desc, s, i);
 	}
 
@@ -779,6 +806,11 @@ static int hns3_dbg_dev_info(struct seq_file *s, void *data)
 static void hns3_dump_page_pool_info(struct hns3_enet_ring *ring,
 				     struct seq_file *s, u32 index)
 {
+	if (!ring->page_pool) {
+		seq_printf(s, "%-10u %s\n", index, "page pool not initialized");
+		return;
+	}
+
 	seq_printf(s, "%-10u%-14u%-14d%-21u%-7u%-9d%uK\n",
 		   index,
 		   READ_ONCE(ring->page_pool->pages_state_hold_cnt),
@@ -796,28 +828,27 @@ static int hns3_dbg_page_pool_info(struct seq_file *s, void *data)
 	struct hns3_enet_ring *ring;
 	u32 i;
 
+	mutex_lock(&priv->ae_handle->dbg_mutex);
 	if (!priv->ring) {
-		dev_err(&h->pdev->dev, "priv->ring is NULL\n");
-		return -EFAULT;
-	}
-
-	if (!priv->ring[h->kinfo.num_tqps].page_pool) {
-		dev_err(&h->pdev->dev, "page pool is not initialized\n");
-		return -EFAULT;
+		mutex_unlock(&priv->ae_handle->dbg_mutex);
+		return -EBUSY;
 	}
 
 	seq_puts(s, "QUEUE_ID  ALLOCATE_CNT  FREE_CNT      ");
 	seq_puts(s, "POOL_SIZE(PAGE_NUM)  ORDER  NUMA_ID  MAX_LEN\n");
 
 	for (i = 0; i < h->kinfo.num_tqps; i++) {
-		if (!test_bit(HNS3_NIC_STATE_INITED, &priv->state) ||
-		    test_bit(HNS3_NIC_STATE_RESETTING, &priv->state))
-			return -EPERM;
+		/* Per-iteration check bounds reset latency to one iteration. */
+		if (hns3_dbg_is_device_busy(priv)) {
+			mutex_unlock(&priv->ae_handle->dbg_mutex);
+			return -EBUSY;
+		}
 
 		ring = &priv->ring[(u32)(i + h->kinfo.num_tqps)];
 		hns3_dump_page_pool_info(ring, s, i);
 	}
 
+	mutex_unlock(&priv->ae_handle->dbg_mutex);
 	return 0;
 }
 
@@ -826,17 +857,23 @@ static int hns3_dbg_bd_info_show(struct seq_file *s, void *private)
 	struct hns3_dbg_data *data = s->private;
 	struct hnae3_handle *h = data->handle;
 	struct hns3_nic_priv *priv = h->priv;
+	int ret;
 
-	if (!test_bit(HNS3_NIC_STATE_INITED, &priv->state) ||
-	    test_bit(HNS3_NIC_STATE_RESETTING, &priv->state))
+	mutex_lock(&priv->ae_handle->dbg_mutex);
+	if (hns3_dbg_is_device_busy(priv)) {
+		mutex_unlock(&priv->ae_handle->dbg_mutex);
 		return -EBUSY;
+	}
 
 	if (data->cmd == HNAE3_DBG_CMD_TX_BD)
-		return hns3_dbg_tx_bd_info(s, private);
+		ret = hns3_dbg_tx_bd_info(s, private);
 	else if (data->cmd == HNAE3_DBG_CMD_RX_BD)
-		return hns3_dbg_rx_bd_info(s, private);
+		ret = hns3_dbg_rx_bd_info(s, private);
+	else
+		ret = -EOPNOTSUPP;
 
-	return -EOPNOTSUPP;
+	mutex_unlock(&priv->ae_handle->dbg_mutex);
+	return ret;
 }
 DEFINE_SHOW_ATTRIBUTE(hns3_dbg_bd_info);
 
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 90f0a8ac9295..472194ba3fcb 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -5456,6 +5456,7 @@ static int hns3_client_init(struct hnae3_handle *handle)
 	priv->min_tx_copybreak = 0;
 	priv->min_tx_spare_buf_size = 0;
 	set_bit(HNS3_NIC_STATE_DOWN, &priv->state);
+	mutex_init(&handle->dbg_mutex);
 
 	handle->msg_enable = netif_msg_init(debug, DEFAULT_MSG_LEVEL);
 
@@ -5569,6 +5570,7 @@ static int hns3_client_init(struct hnae3_handle *handle)
 	priv->ring = NULL;
 out_get_ring_cfg:
 	priv->ae_handle = NULL;
+	mutex_destroy(&handle->dbg_mutex);
 	free_netdev(netdev);
 	return ret;
 }
@@ -5592,6 +5594,7 @@ static void hns3_client_uninit(struct hnae3_handle *handle, bool reset)
 
 	hns3_free_rx_cpu_rmap(netdev);
 
+	mutex_lock(&handle->dbg_mutex);
 	hns3_nic_uninit_irq(priv);
 
 	hns3_clear_all_ring(handle, true);
@@ -5603,9 +5606,11 @@ static void hns3_client_uninit(struct hnae3_handle *handle, bool reset)
 	hns3_uninit_all_ring(priv);
 
 	hns3_put_ring_config(priv);
+	mutex_unlock(&handle->dbg_mutex);
 
 out_netdev_free:
 	hns3_dbg_uninit(handle);
+	mutex_destroy(&handle->dbg_mutex);
 	free_netdev(netdev);
 }
 
@@ -5882,6 +5887,7 @@ static int hns3_reset_notify_uninit_enet(struct hnae3_handle *handle)
 		return 0;
 	}
 
+	mutex_lock(&handle->dbg_mutex);
 	hns3_free_rx_cpu_rmap(netdev);
 	hns3_nic_uninit_irq(priv);
 	hns3_clear_all_ring(handle, true);
@@ -5894,6 +5900,7 @@ static int hns3_reset_notify_uninit_enet(struct hnae3_handle *handle)
 	hns3_uninit_all_ring(priv);
 
 	hns3_put_ring_config(priv);
+	mutex_unlock(&handle->dbg_mutex);
 
 	return 0;
 }
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
index 14642f81efe1..7005d8b2d010 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
@@ -1252,6 +1252,7 @@ static int hns3_set_ringparam(struct net_device *ndev,
 	if (if_running)
 		ndev->netdev_ops->ndo_stop(ndev);
 
+	mutex_lock(&h->dbg_mutex);
 	hns3_change_all_ring_bd_num(priv, new_ringparam.tx_desc_num,
 				    new_ringparam.rx_desc_num);
 	hns3_change_rx_buf_len(ndev, new_ringparam.rx_buf_len);
@@ -1270,6 +1271,7 @@ static int hns3_set_ringparam(struct net_device *ndev,
 		for (i = 0; i < h->kinfo.num_tqps * 2; i++)
 			hns3_fini_ring(&tmp_rings[i]);
 	}
+	mutex_unlock(&h->dbg_mutex);
 
 	kfree(tmp_rings);
 
-- 
2.43.0

Re: [PATCH v4 net 0/4] net: hns3: fix multiple bugs in reset/error paths

[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 LLM and not proven at runtime). If it was triggered
   please include the symptoms, like the stack trace or kernel messages.

 - What hardware the change was tested on. For driver fixes please
   mention the device (and if relevant firmware version) used for
   testing, or say that the change was not tested on real hardware.

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.