linux-kernel - Re: [PATCH] scsi: ufs: ufshcd-pltfrm: fix memory leak due to probe defer

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Date:   Wed, 20 Oct 2021 16:47:47 +0100
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     alim.akhtar@...sung.com, avri.altman@....com, jejb@...ux.ibm.com,
        martin.petersen@...cle.com
Cc:     draviv@...eaurora.org, sthumma@...eaurora.org,
        linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
        bjorn.andersson@...aro.org
Subject: Re: [PATCH] scsi: ufs: ufshcd-pltfrm: fix memory leak due to probe
 defer



On 14/09/2021 10:22, Srinivas Kandagatla wrote:
> UFS drivers that probe defer will endup leaking memory allocated for
> clk and regulator names via kstrdup because the structure that is
> holding this memory is allocated via devm_* variants which will be
> freed during probe defer but the names are never freed.
> 
> Use same devm_* variant of kstrdup to free the memory allocated to
> name when driver probe defers.
> 
> Kmemleak found around 11 leaks on Qualcomm Dragon Board RB5:
> 
> unreferenced object 0xffff66f243fb2c00 (size 128):
>    comm "kworker/u16:0", pid 7, jiffies 4294893319 (age 94.848s)
>    hex dump (first 32 bytes):
>      63 6f 72 65 5f 63 6c 6b 00 76 69 72 74 75 61 6c  core_clk.virtual
>      2f 77 6f 72 6b 71 75 65 75 65 2f 73 63 73 69 5f  /workqueue/scsi_
>    backtrace:
>      [<000000006f788cd1>] slab_post_alloc_hook+0x88/0x410
>      [<00000000cfd1372b>] __kmalloc_track_caller+0x138/0x230
>      [<00000000a92ab17b>] kstrdup+0xb0/0x110
>      [<0000000037263ab6>] ufshcd_pltfrm_init+0x1a8/0x500
>      [<00000000a20a5caa>] ufs_qcom_probe+0x20/0x58
>      [<00000000a5e43067>] platform_probe+0x6c/0x118
>      [<00000000ef686e3f>] really_probe+0xc4/0x330
>      [<000000005b18792c>] __driver_probe_device+0x88/0x118
>      [<00000000a5d295e8>] driver_probe_device+0x44/0x158
>      [<000000007e83f58d>] __device_attach_driver+0xb4/0x128
>      [<000000004bfa4470>] bus_for_each_drv+0x68/0xd0
>      [<00000000b89a83bc>] __device_attach+0xec/0x170
>      [<00000000ada2beea>] device_initial_probe+0x14/0x20
>      [<0000000079921612>] bus_probe_device+0x9c/0xa8
>      [<00000000d268bf7c>] deferred_probe_work_func+0x90/0xd0
>      [<000000009ef64bfa>] process_one_work+0x29c/0x788
> unreferenced object 0xffff66f243fb2c80 (size 128):
>    comm "kworker/u16:0", pid 7, jiffies 4294893319 (age 94.848s)
>    hex dump (first 32 bytes):
>      62 75 73 5f 61 67 67 72 5f 63 6c 6b 00 00 00 00  bus_aggr_clk....
>      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> 
> with this patch no memory leaks are reported.
> Fixes: aa4976130934 ("ufs: Add regulator enable support")
> Fixes: c6e79dacd86f ("ufs: Add clock initialization support")
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
> ---

Gentle Ping ?

This is not a critical issue, but it will be nice to get this fixed 
atleast in 5.16 release.

--srini

>   drivers/scsi/ufs/ufshcd-pltfrm.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
> index 8859c13f4e09..eaeae83b999f 100644
> --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
> +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
> @@ -91,7 +91,7 @@ static int ufshcd_parse_clock_info(struct ufs_hba *hba)
>   
>   		clki->min_freq = clkfreq[i];
>   		clki->max_freq = clkfreq[i+1];
> -		clki->name = kstrdup(name, GFP_KERNEL);
> +		clki->name = devm_kstrdup(dev, name, GFP_KERNEL);
>   		if (!strcmp(name, "ref_clk"))
>   			clki->keep_link_active = true;
>   		dev_dbg(dev, "%s: min %u max %u name %s\n", "freq-table-hz",
> @@ -126,7 +126,7 @@ static int ufshcd_populate_vreg(struct device *dev, const char *name,
>   	if (!vreg)
>   		return -ENOMEM;
>   
> -	vreg->name = kstrdup(name, GFP_KERNEL);
> +	vreg->name = devm_kstrdup(dev, name, GFP_KERNEL);
>   
>   	snprintf(prop_name, MAX_PROP_SIZE, "%s-max-microamp", name);
>   	if (of_property_read_u32(np, prop_name, &vreg->max_uA)) {
>