From: Tariq Toukan <tariqt@nvidia.com>
To: Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, <netdev@vger.kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: Carolina Jubran <cjubran@nvidia.com>, Chris Mi <cmi@nvidia.com>,
"Gal Pressman" <gal@nvidia.com>, Kees Cook <kees@kernel.org>,
Leon Romanovsky <leon@kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-rdma@vger.kernel.org>, Mark Bloch <mbloch@nvidia.com>,
Oz Shlomo <ozsh@nvidia.com>, Saeed Mahameed <saeedm@nvidia.com>,
Shahar Shitrit <shshitrit@nvidia.com>,
Tariq Toukan <tariqt@nvidia.com>
Subject: [PATCH net] net/mlx5e: Fix use-after-free race in sample_restore_put()
Date: Wed, 2 Sep 2026 22:33:41 +0300 [thread overview]
Message-ID: <20260902193341.3668809-1-tariqt@nvidia.com> (raw)
From: Carolina Jubran <cjubran@nvidia.com>
Concurrent teardown of TC sample rules sharing the same restore
context may re-read restore->count after dropping restore_lock.
At that point another thread may already have completed cleanup and
freed the restore object.
Use the result of the refcount decrement while holding restore_lock to
determine whether cleanup is needed.
Fixes: 36a3196256bf ("net/mlx5e: TC, Add sampler restore handle API")
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
drivers/net/ethernet/mellanox/mlx5/core/en/tc/sample.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc/sample.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc/sample.c
index 89490f687a9c..93c62d3f3e5b 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc/sample.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc/sample.c
@@ -311,12 +311,15 @@ sample_restore_get(struct mlx5e_tc_psample *tc_psample, u32 obj_id,
static void
sample_restore_put(struct mlx5e_tc_psample *tc_psample, struct mlx5e_sample_restore *restore)
{
+ bool last;
+
mutex_lock(&tc_psample->restore_lock);
- if (--restore->count == 0)
+ last = --restore->count == 0;
+ if (last)
hash_del(&restore->hlist);
mutex_unlock(&tc_psample->restore_lock);
- if (!restore->count) {
+ if (last) {
mlx5_del_flow_rules(restore->rule);
mlx5_modify_header_dealloc(tc_psample->esw->dev, restore->modify_hdr);
kfree(restore);
--
2.44.0
reply other threads:[~2026-09-02 19:34 UTC|newest]
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