RE: [net PATCH] net: fec: free fec queue when fec_enet_mii_init() fails

[Wei Fang]

> -----Original Message-----
> From: Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx>
> Sent: 2024年5月22日 10:13
> To: Wei Fang <wei.fang@xxxxxxx>; Shenwei Wang
> <shenwei.wang@xxxxxxx>; Clark Wang <xiaoning.wang@xxxxxxx>;
> davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx;
> pabeni@xxxxxxxxxx
> Cc: imx@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: [net PATCH] net: fec: free fec queue when fec_enet_mii_init() fails
> 
> commit 63e3cc2b87c2 ("arm64: dts: imx93-11x11-evk: add
> reset gpios for ethernet PHYs") the rese-gpios attribute
nit: reset-gpios

> is added, but this pcal6524 is loaded later, which causes
> fec driver defer, the following memory leak occurs.
> 
> unreferenced object 0xffffff8010350000 (size 8192):
>   comm "kworker/u8:3", pid 39, jiffies 4294893562
>   hex dump (first 32 bytes):
>     02 00 00 00 00 00 00 00 00 50 06 8a c0 ff ff ff  .........P......
>     e0 6f 06 8a c0 ff ff ff 00 50 06 8a c0 ff ff ff  .o.......P......
>   backtrace (crc f1b8b79f):
>     [<0000000057d2c6ae>] kmemleak_alloc+0x34/0x40
>     [<000000003c413e60>] kmalloc_trace+0x2f8/0x460
>     [<00000000663f64e6>] fec_probe+0x1364/0x3a04
>     [<0000000024d7e427>] platform_probe+0xc4/0x198
>     [<00000000293aa124>] really_probe+0x17c/0x4f0
>     [<00000000dfd1e0f3>] __driver_probe_device+0x158/0x2c4
>     [<000000004ae0034a>] driver_probe_device+0x60/0x18c
>     [<00000000fa3ad0e1>] __device_attach_driver+0x168/0x208
>     [<00000000394a38d3>] bus_for_each_drv+0x104/0x190
>     [<00000000c44e3dea>] __device_attach+0x1f8/0x33c
>     [<000000004db69c14>] device_initial_probe+0x14/0x20
>     [<00000000f4705309>] bus_probe_device+0x128/0x158
>     [<00000000f7115919>] deferred_probe_work_func+0x12c/0x1d8
>     [<0000000012315b3b>] process_scheduled_works+0x6c0/0x164c
>     [<0000000089b2b6e1>] worker_thread+0x370/0x95c
>     [<000000004dbe3d1a>] kthread+0x360/0x420
> 
> Fixes: 63e3cc2b87c2 ("arm64: dts: imx93-11x11-evk: add reset gpios for
> ethernet PHYs")

I don't think this commit should be blamed, because this issue should
have existed earlier, it is just pcal6524 driver is loaded later than the
fec driver, which triggers this issue.

The commit 59d0f7465644 ("net: fec: init multi queue date structure")
was the first to introduce this issue, commit 619fee9eb13b
("net: fec: fix the potential memory leak in fec_enet_init() ")
fixed this, but it does not seem to be completely fixed.

We should find the correct blamed commit so that stable maintainers
can backport to the correct kernel version.

> Signed-off-by: Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx>
> ---
>  drivers/net/ethernet/freescale/fec_main.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c
> index a72d8a2eb0b3..2b3534d434d8 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -4524,6 +4524,7 @@ fec_probe(struct platform_device *pdev)
>  	fec_enet_mii_remove(fep);
>  failed_mii_init:
>  failed_irq:
> +	fec_enet_free_queue(ndev);
>  failed_init:
>  	fec_ptp_stop(pdev);
>  failed_reset:
> --
> 2.25.1