net: hns3: fix double free issue for tx spare buffer

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In hns3_set_ringparam(), a temporary copy (tmp_rings) of the ring structure
is created for rollback. However, the tx_spare pointer in the original
ring handle is incorrectly left pointing to the old backup memory.

Later, if memory allocation fails in hns3_init_all_ring() during the setup,
the error path attempts to free all newly allocated rings. Since tx_spare
contains a stale (non-NULL) pointer from the backup, it is mistaken for
a newly allocated buffer and is erroneously freed, leading to a double-free
of the backup memory.

The root cause is that the tx_spare field was not cleared after its value
was saved in tmp_rings, leaving a dangling pointer.

Fix this by setting tx_spare to NULL in the original ring structure
when the creation of the new `tx_spare` fails. This ensures the
error cleanup path only frees genuinely newly allocated buffers.

Fixes: 907676b130 ("net: hns3: use tx bounce buffer for small packets")
Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260205121719.3285730-1-shaojijie@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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Jian Shen 2026-02-05 20:17:19 +08:00 • committed by Jakub Kicinski

parent 5d41f95f5d

commit 6d2f142b1e

1 changed files with 9 additions and 2 deletions

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drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

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