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Message-ID: <0bbab386-70ef-5c1a-1007-d2e26346bdd3@gmx.de>
Date: Fri, 31 Mar 2023 23:30:15 +0200
From: Armin Wolf <W_Armin@....de>
To: Mirsad Goran Todorovac <mirsad.todorovac@....unizg.hr>,
markpearson@...ovo.com
Cc: hdegoede@...hat.com, markgross@...nel.org, thomas@...ch.de,
gregkh@...uxfoundation.org, rafael@...nel.org,
platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] platform/x86: think-lmi: Fix memory leak when showing
current settings
Am 31.03.23 um 22:23 schrieb Mirsad Goran Todorovac:
> On 31. 03. 2023. 20:09, Armin Wolf wrote:
>> When retriving a item string with tlmi_setting(), the result has to be
>> freed using kfree(). In current_value_show() however, malformed
>> item strings are not freed, causing a memory leak.
>> Fix this by eliminating the early return responsible for this.
>>
>> Reported-by: Mirsad Goran Todorovac <mirsad.todorovac@....unizg.hr>
>> Link: https://lore.kernel.org/platform-driver-x86/01e920bc-5882-ba0c-dd15-868bf0eca0b8@alu.unizg.hr/T/#t
>> Fixes: a40cd7ef22fb ("platform/x86: think-lmi: Add WMI interface support on Lenovo platforms")
>> Signed-off-by: Armin Wolf <W_Armin@....de>
>> ---
>> Changes in v2:
>> - Add Reported-by: and Link: tags
>> ---
>> drivers/platform/x86/think-lmi.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
>> index cc66f7cbccf2..8cafb9d4016c 100644
>> --- a/drivers/platform/x86/think-lmi.c
>> +++ b/drivers/platform/x86/think-lmi.c
>> @@ -930,10 +930,12 @@ static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *a
>> /* validate and split from `item,value` -> `value` */
>> value = strpbrk(item, ",");
>> if (!value || value == item || !strlen(value + 1))
>> - return -EINVAL;
>> + ret = -EINVAL;
>> + else
>> + ret = sysfs_emit(buf, "%s\n", value + 1);
>>
>> - ret = sysfs_emit(buf, "%s\n", value + 1);
>> kfree(item);
>> +
>> return ret;
>> }
>>
>> --
>> 2.30.2
> I can confirm that the test passed in the original environment that caused the kmemleak.
>
> [root@...mtodorov marvin]# cat /sys/kernel/debug/kmemleak
> unreferenced object 0xffff8e614889e390 (size 16):
> comm "kworker/u12:5", pid 366, jiffies 4294896428 (age 93.704s)
> hex dump (first 16 bytes):
> 6d 65 6d 73 74 69 63 6b 30 00 cc cc cc cc cc cc memstick0.......
> backtrace:
> [<ffffffff860fb26c>] slab_post_alloc_hook+0x8c/0x3e0
> [<ffffffff86102b49>] __kmem_cache_alloc_node+0x1d9/0x2a0
> [<ffffffff860773c9>] __kmalloc_node_track_caller+0x59/0x180
> [<ffffffff86066a1a>] kstrdup+0x3a/0x70
> [<ffffffff86066a8c>] kstrdup_const+0x2c/0x40
> [<ffffffff864a987c>] kvasprintf_const+0x7c/0xb0
> [<ffffffff86e3b427>] kobject_set_name_vargs+0x27/0xa0
> [<ffffffff8678ed17>] dev_set_name+0x57/0x80
> [<ffffffffc0e49f0f>] memstick_check+0x10f/0x3b0 [memstick]
> [<ffffffff85dcb4c0>] process_one_work+0x250/0x530
> [<ffffffff85dcb7f8>] worker_thread+0x48/0x3a0
> [<ffffffff85dd6dff>] kthread+0x10f/0x140
> [<ffffffff85c02fa9>] ret_from_fork+0x29/0x50
> unreferenced object 0xffff8e6158f93b90 (size 16):
> comm "kworker/u12:5", pid 366, jiffies 4294896433 (age 93.684s)
> hex dump (first 16 bytes):
> 6d 65 6d 73 74 69 63 6b 30 00 cc cc cc cc cc cc memstick0.......
> backtrace:
> [<ffffffff860fb26c>] slab_post_alloc_hook+0x8c/0x3e0
> [<ffffffff86102b49>] __kmem_cache_alloc_node+0x1d9/0x2a0
> [<ffffffff860773c9>] __kmalloc_node_track_caller+0x59/0x180
> [<ffffffff86066a1a>] kstrdup+0x3a/0x70
> [<ffffffff86066a8c>] kstrdup_const+0x2c/0x40
> [<ffffffff864a987c>] kvasprintf_const+0x7c/0xb0
> [<ffffffff86e3b427>] kobject_set_name_vargs+0x27/0xa0
> [<ffffffff8678ed17>] dev_set_name+0x57/0x80
> [<ffffffffc0e49f0f>] memstick_check+0x10f/0x3b0 [memstick]
> [<ffffffff85dcb4c0>] process_one_work+0x250/0x530
> [<ffffffff85dcb7f8>] worker_thread+0x48/0x3a0
> [<ffffffff85dd6dff>] kthread+0x10f/0x140
> [<ffffffff85c02fa9>] ret_from_fork+0x29/0x50
> [root@...mtodorov marvin]# uname -rms
> Linux 6.3.0-rc4-00034-gfcd476ea6a88-dirty x86_64
> [root@...mtodorov marvin]#
>
> NOTE: The leaks here belong to drivers/memstick/core/memstick.c leak for which I have
> proposed a fix in message <df560535-2a8e-de21-d45d-805159d70954@....unizg.hr>.
>
> This test was built on the 6.3-rc4+ commit fcd476ea6a88 Torvalds tree + the following
> patches (Armin's, and Thomas's).
>
> drivers/platform/x86/think-lmi.c | 18 ++++++++++--------
> drivers/usb/host/xhci.c | 1 +
> 2 files changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
> index c816646eb661..c2146add88ab 100644
> --- a/drivers/platform/x86/think-lmi.c
> +++ b/drivers/platform/x86/think-lmi.c
> @@ -930,10 +930,12 @@ static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *a
> /* validate and split from `item,value` -> `value` */
> value = strpbrk(item, ",");
> if (!value || value == item || !strlen(value + 1))
> - return -EINVAL;
> + ret = -EINVAL;
> + else
> + ret = sysfs_emit(buf, "%s\n", value + 1);
>
> - ret = sysfs_emit(buf, "%s\n", value + 1);
> kfree(item);
> +
> return ret;
> }
>
> @@ -1380,7 +1382,6 @@ static struct tlmi_pwd_setting *tlmi_create_auth(const char *pwd_type,
>
> static int tlmi_analyze(void)
> {
> - acpi_status status;
> int i, ret;
>
> if (wmi_has_guid(LENOVO_SET_BIOS_SETTINGS_GUID) &&
> @@ -1417,8 +1418,8 @@ static int tlmi_analyze(void)
> char *p;
>
> tlmi_priv.setting[i] = NULL;
> - status = tlmi_setting(i, &item, LENOVO_BIOS_SETTING_GUID);
> - if (ACPI_FAILURE(status))
> + ret = tlmi_setting(i, &item, LENOVO_BIOS_SETTING_GUID);
> + if (ret)
> break;
> if (!item)
> break;
> @@ -1457,10 +1458,10 @@ static int tlmi_analyze(void)
> * name string.
> * Try and pull that out if it's available.
> */
> - char *item, *optstart, *optend;
> + char *optitem, *optstart, *optend;
>
> - if (!tlmi_setting(setting->index, &item, LENOVO_BIOS_SETTING_GUID)) {
> - optstart = strstr(item, "[Optional:");
> + if (!tlmi_setting(setting->index, &optitem, LENOVO_BIOS_SETTING_GUID)) {
> + optstart = strstr(optitem, "[Optional:");
> if (optstart) {
> optstart += strlen("[Optional:");
> optend = strstr(optstart, "]");
> @@ -1469,6 +1470,7 @@ static int tlmi_analyze(void)
> kstrndup(optstart, optend - optstart,
> GFP_KERNEL);
> }
> + kfree(optitem);
> }
> }
> /*
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 6183ce8574b1..905f1e89ead8 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -4438,6 +4438,7 @@ static int __maybe_unused xhci_change_max_exit_latency(struct xhci_hcd *xhci,
>
> if (!virt_dev || max_exit_latency == virt_dev->current_mel) {
> spin_unlock_irqrestore(&xhci->lock, flags);
> + xhci_free_command(xhci, command);
> return 0;
> }
>
> Xhci patch from Mathias is included because it is well tested and already submitted and acked.
>
> At your convenience and according to the Code of Conduct, you can add:
>
> Tested-by: Mirsad Goran Todorovac <mirsad.todorovac@....unizg.hr>
>
> Otherwise, Armin, I think you should submit this patch rightly because all idea to search in
> think-lmi.c was yours.
>
> Bisect was also much faster and in fewer steps.
>
> Thanks,
> Mirsad
>
Thank you for reporting the memory leak issues and testing the patches.
I will send a v3 of my patch soon which will contain your Tested-by: tag.
Armin Wolf
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