[PATCH net v3 0/2] net: stmmac: misc fixes

[PATCH net v3 0/2] net: stmmac: misc fixes

[Konrad Leszczynski]

This series adds two fixes addressing KASAN panic on ethtool usage and
flow stop on TC block setup when interface down.

Patchset has been created as a result of discussion at [1].

v2 can be found at [2].

[1] https://lore.kernel.org/netdev/20250826113247.3481273-1-konrad.leszczynski@intel.com/
[2] https://lore.kernel.org/netdev/20250828100237.4076570-1-konrad.leszczynski@intel.com/

v2 -> v3:
- replace strcpy with ethtool_puts per suggestion
- removed extension patch for printing enhanced descriptors

v1 -> v2:
- add missing Fixes lines
- add missing SoB lines
- removed all non-fix patches. These will be sent in separate series

Karol Jurczenia (1):
  net: stmmac: check if interface is running before TC block setup

Konrad Leszczynski (1):
  net: stmmac: replace memcpy with ethtool_puts in ethtool

 drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c | 2 +-
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c    | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

-- 
2.34.1

[PATCH net v3 1/2] net: stmmac: replace memcpy with ethtool_puts in ethtool

[Konrad Leszczynski]

Fix kernel exception by replacing memcpy with ethtool_puts when used with
safety feature strings in ethtool logic.

[  +0.000023] BUG: KASAN: global-out-of-bounds in stmmac_get_strings+0x17d/0x520 [stmmac]
[  +0.000115] Read of size 32 at addr ffffffffc0cfab20 by task ethtool/2571

[  +0.000005] Call Trace:
[  +0.000004]  <TASK>
[  +0.000003]  dump_stack_lvl+0x6c/0x90
[  +0.000016]  print_report+0xce/0x610
[  +0.000011]  ? stmmac_get_strings+0x17d/0x520 [stmmac]
[  +0.000108]  ? kasan_addr_to_slab+0xd/0xa0
[  +0.000008]  ? stmmac_get_strings+0x17d/0x520 [stmmac]
[  +0.000101]  kasan_report+0xd4/0x110
[  +0.000010]  ? stmmac_get_strings+0x17d/0x520 [stmmac]
[  +0.000102]  kasan_check_range+0x3a/0x1c0
[  +0.000010]  __asan_memcpy+0x24/0x70
[  +0.000008]  stmmac_get_strings+0x17d/0x520 [stmmac]

Reviewed-by: Sebastian Basierski <sebastian.basierski@intel.com>
Signed-off-by: Konrad Leszczynski <konrad.leszczynski@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index 77758a7299b4..d5a2b7e9b2a9 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -752,7 +752,7 @@ static void stmmac_get_strings(struct net_device *dev, u32 stringset, u8 *data)
 				if (!stmmac_safety_feat_dump(priv,
 							&priv->sstats, i,
 							NULL, &desc)) {
-					memcpy(p, desc, ETH_GSTRING_LEN);
+					ethtool_puts(&p, desc);
 					p += ETH_GSTRING_LEN;
 				}
 			}
-- 
2.34.1

[PATCH net v3 2/2] net: stmmac: check if interface is running before TC block setup

[Konrad Leszczynski]

From: Karol Jurczenia <karol.jurczenia@intel.com>

If the interface is down before setting a TC block, the queues are already
disabled and setup cannot proceed.

Reviewed-by: Konrad Leszczynski <konrad.leszczynski@intel.com>
Reviewed-by: Sebastian Basierski <sebastian.basierski@intel.com>
Signed-off-by: Karol Jurczenia <karol.jurczenia@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 7b16d1207b80..133ffdc91153 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -6247,6 +6247,9 @@ static int stmmac_setup_tc_block_cb(enum tc_setup_type type, void *type_data,
 	struct stmmac_priv *priv = cb_priv;
 	int ret = -EOPNOTSUPP;
 
+	if (!netif_running(priv->dev))
+		return -EINVAL;
+
 	if (!tc_cls_can_offload_and_chain0(priv->dev, type_data))
 		return ret;
 
-- 
2.34.1

Re: [PATCH net v3 1/2] net: stmmac: replace memcpy with ethtool_puts in ethtool

[Simon Horman]

On Tue, Sep 16, 2025 at 11:25:06AM +0200, Konrad Leszczynski wrote:
> Fix kernel exception by replacing memcpy with ethtool_puts when used with
> safety feature strings in ethtool logic.
> 
> [  +0.000023] BUG: KASAN: global-out-of-bounds in stmmac_get_strings+0x17d/0x520 [stmmac]
> [  +0.000115] Read of size 32 at addr ffffffffc0cfab20 by task ethtool/2571
> 
> [  +0.000005] Call Trace:
> [  +0.000004]  <TASK>
> [  +0.000003]  dump_stack_lvl+0x6c/0x90
> [  +0.000016]  print_report+0xce/0x610
> [  +0.000011]  ? stmmac_get_strings+0x17d/0x520 [stmmac]
> [  +0.000108]  ? kasan_addr_to_slab+0xd/0xa0
> [  +0.000008]  ? stmmac_get_strings+0x17d/0x520 [stmmac]
> [  +0.000101]  kasan_report+0xd4/0x110
> [  +0.000010]  ? stmmac_get_strings+0x17d/0x520 [stmmac]
> [  +0.000102]  kasan_check_range+0x3a/0x1c0
> [  +0.000010]  __asan_memcpy+0x24/0x70
> [  +0.000008]  stmmac_get_strings+0x17d/0x520 [stmmac]

I think it would be worth adding some commentary around
why memcpy results in this problem in this case.

> 
> Reviewed-by: Sebastian Basierski <sebastian.basierski@intel.com>
> Signed-off-by: Konrad Leszczynski <konrad.leszczynski@intel.com>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
> index 77758a7299b4..d5a2b7e9b2a9 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
> @@ -752,7 +752,7 @@ static void stmmac_get_strings(struct net_device *dev, u32 stringset, u8 *data)
>  				if (!stmmac_safety_feat_dump(priv,
>  							&priv->sstats, i,
>  							NULL, &desc)) {
> -					memcpy(p, desc, ETH_GSTRING_LEN);
> +					ethtool_puts(&p, desc);
>  					p += ETH_GSTRING_LEN;

ethtool_puts() increments p, so I think the line above should be removed.

>  				}
>  			}
> -- 
> 2.34.1
> 
> 

Re: [PATCH net v3 0/2] net: stmmac: misc fixes

[Jakub Kicinski]

On Tue, 16 Sep 2025 11:25:05 +0200 Konrad Leszczynski wrote:
> This series adds two fixes addressing KASAN panic on ethtool usage and
> flow stop on TC block setup when interface down.
> 
> Patchset has been created as a result of discussion at [1].

Please make sure you wait 24h between repostings, per:
https://www.kernel.org/doc/html/next/process/maintainer-netdev.html
-- 
pv-bot: 24h