Re: [BUG] [BISECTED] [CORRECTION] systemd-devd triggers kernel memleak apparently in drivers/core/dd.c: driver_register()

[Mirsad Goran Todorovac]

On 29.3.2023. 15:35, Thomas Weißschuh wrote:
> Mar 29, 2023 08:31:31 Mirsad Goran Todorovac <mirsad.todorovac@xxxxxxxxxxxx>:
>
> > Hi, again,
> >
> > NOTE: I forgot to rewind to the first bad commit. So please ignore
> > the previous email.
> >
> > On 29.3.2023. 15:22, Mirsad Goran Todorovac wrote:
> > > Hi, Armin, Mr. Greg,
> > > On 29.3.2023. 10:13, Mirsad Goran Todorovac wrote:
> > > > On 28.3.2023. 21:55, Armin Wolf wrote:
> > > > > Am 28.03.23 um 21:06 schrieb Mirsad Goran Todorovac:
> > > > >
> > > > > > On 3/28/2023 6:53 PM, Armin Wolf wrote:
> > > > > > > …
> > > > > >
> > > > > > Hi Armin,
> > > > > >
> > > > > > I tried your suggestion, and though it is an obvious improvement and a
> > > > > > leak fix, this
> > > > > > was not the one we were searching for.
> > > > > >
> > > > > > I tested the following patch:
> > > > > >
> > > > > > diff --git a/drivers/platform/x86/think-lmi.c
> > > > > > b/drivers/platform/x86/think-lmi.c
> > > > > > index c816646eb661..1e77ecb0cba8 100644
> > > > > > --- a/drivers/platform/x86/think-lmi.c
> > > > > > +++ b/drivers/platform/x86/think-lmi.c
> > > > > > @@ -929,8 +929,10 @@ 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))
> > > > > > +       if (!value || value == item || !strlen(value + 1)) {
> > > > > > +               kfree(item);
> > > > > >                  return -EINVAL;
> > > > > > +       }
> > > > > >
> > > > > >          ret = sysfs_emit(buf, "%s\n", value + 1);
> > > > > >          kfree(item);
> > > > > >
> > > > > > (I would also object to the use of strlen() here, for it is inherently
> > > > > > insecure
> > > > > > against SEGFAULT in kernel space.)
> > > > > >
> > > > > > I still get:
> > > > > > [root@pc-mtodorov marvin]# uname -rms
> > > > > > Linux 6.3.0-rc4-armin-patch-00025-g3a93e40326c8-dirty x86_64
> > > > > > [root@pc-mtodorov marvin]# cat /sys/kernel/debug/kmemleak [edited]
> > > > > > unreferenced object 0xffff8eb008ef9260 (size 96):
> > > > > >    comm "systemd-udevd", pid 771, jiffies 4294896499 (age 74.880s)
> > > > > >    hex dump (first 32 bytes):
> > > > > >      53 65 72 69 61 6c 50 6f 72 74 31 41 64 64 72 65 SerialPort1Addre
> > > > > >      73 73 2c 33 46 38 2f 49 52 51 34 3b 5b 4f 70 74 ss,3F8/IRQ4;[Opt
> > > > > >    backtrace:
> > > > > >      [<ffffffff9eafb26c>] slab_post_alloc_hook+0x8c/0x3e0
> > > > > >      [<ffffffff9eb02b49>] __kmem_cache_alloc_node+0x1d9/0x2a0
> > > > > >      [<ffffffff9ea773c9>] __kmalloc_node_track_caller+0x59/0x180
> > > > > >      [<ffffffff9ea66a1a>] kstrdup+0x3a/0x70
> > > > > >      [<ffffffffc0eef9aa>] tlmi_extract_output_string.isra.0+0x2a/0x60
> > > > > > [think_lmi]
> > > > > >      [<ffffffffc0eefb64>] tlmi_setting.constprop.4+0x54/0x90 [think_lmi]
> > > > > >      [<ffffffffc0ef02c1>] tlmi_probe+0x591/0xba0 [think_lmi]
> > > > > >      [<ffffffffc0629c53>] wmi_dev_probe+0x163/0x230 [wmi]
> > > > > >      [<ffffffff9f1987eb>] really_probe+0x17b/0x3d0
> > > > > >      [<ffffffff9f198ad4>] __driver_probe_device+0x84/0x190
> > > > > >      [<ffffffff9f198c14>] driver_probe_device+0x24/0xc0
> > > > > >      [<ffffffff9f198ed2>] __driver_attach+0xc2/0x190
> > > > > >      [<ffffffff9f195ab1>] bus_for_each_dev+0x81/0xd0
> > > > > >      [<ffffffff9f197c62>] driver_attach+0x22/0x30
> > > > > >      [<ffffffff9f197354>] bus_add_driver+0x1b4/0x240
> > > > > >      [<ffffffff9f19a0a2>] driver_register+0x62/0x120
> > > > > > unreferenced object 0xffff8eb018ddbb40 (size 64):
> > > > > >    comm "systemd-udevd", pid 771, jiffies 4294896528 (age 74.780s)
> > > > > >    hex dump (first 32 bytes):
> > > > > >      55 53 42 50 6f 72 74 41 63 63 65 73 73 2c 45 6e USBPortAccess,En
> > > > > >      61 62 6c 65 64 3b 5b 4f 70 74 69 6f 6e 61 6c 3a abled;[Optional:
> > > > > >    backtrace:
> > > > > >      [<ffffffff9eafb26c>] slab_post_alloc_hook+0x8c/0x3e0
> > > > > >      [<ffffffff9eb02b49>] __kmem_cache_alloc_node+0x1d9/0x2a0
> > > > > >      [<ffffffff9ea773c9>] __kmalloc_node_track_caller+0x59/0x180
> > > > > >      [<ffffffff9ea66a1a>] kstrdup+0x3a/0x70
> > > > > >      [<ffffffffc0eef9aa>] tlmi_extract_output_string.isra.0+0x2a/0x60
> > > > > > [think_lmi]
> > > > > >      [<ffffffffc0eefb64>] tlmi_setting.constprop.4+0x54/0x90 [think_lmi]
> > > > > >      [<ffffffffc0ef02c1>] tlmi_probe+0x591/0xba0 [think_lmi]
> > > > > >      [<ffffffffc0629c53>] wmi_dev_probe+0x163/0x230 [wmi]
> > > > > >      [<ffffffff9f1987eb>] really_probe+0x17b/0x3d0
> > > > > >      [<ffffffff9f198ad4>] __driver_probe_device+0x84/0x190
> > > > > >      [<ffffffff9f198c14>] driver_probe_device+0x24/0xc0
> > > > > >      [<ffffffff9f198ed2>] __driver_attach+0xc2/0x190
> > > > > >      [<ffffffff9f195ab1>] bus_for_each_dev+0x81/0xd0
> > > > > >      [<ffffffff9f197c62>] driver_attach+0x22/0x30
> > > > > >      [<ffffffff9f197354>] bus_add_driver+0x1b4/0x240
> > > > > >      [<ffffffff9f19a0a2>] driver_register+0x62/0x120
> > > > > > unreferenced object 0xffff8eb006fe2b40 (size 64):
> > > > > >    comm "systemd-udevd", pid 771, jiffies 4294896542 (age 74.724s)
> > > > > >    hex dump (first 32 bytes):
> > > > > >      55 53 42 42 49 4f 53 53 75 70 70 6f 72 74 2c 45 USBBIOSSupport,E
> > > > > >      6e 61 62 6c 65 64 3b 5b 4f 70 74 69 6f 6e 61 6c nabled;[Optional
> > > > > >    backtrace:
> > > > > >      [<ffffffff9eafb26c>] slab_post_alloc_hook+0x8c/0x3e0
> > > > > >      [<ffffffff9eb02b49>] __kmem_cache_alloc_node+0x1d9/0x2a0
> > > > > >      [<ffffffff9ea773c9>] __kmalloc_node_track_caller+0x59/0x180
> > > > > >      [<ffffffff9ea66a1a>] kstrdup+0x3a/0x70
> > > > > >      [<ffffffffc0eef9aa>] tlmi_extract_output_string.isra.0+0x2a/0x60
> > > > > > [think_lmi]
> > > > > >      [<ffffffffc0eefb64>] tlmi_setting.constprop.4+0x54/0x90 [think_lmi]
> > > > > >      [<ffffffffc0ef02c1>] tlmi_probe+0x591/0xba0 [think_lmi]
> > > > > >      [<ffffffffc0629c53>] wmi_dev_probe+0x163/0x230 [wmi]
> > > > > >      [<ffffffff9f1987eb>] really_probe+0x17b/0x3d0
> > > > > >      [<ffffffff9f198ad4>] __driver_probe_device+0x84/0x190
> > > > > >      [<ffffffff9f198c14>] driver_probe_device+0x24/0xc0
> > > > > >      [<ffffffff9f198ed2>] __driver_attach+0xc2/0x190
> > > > > >      [<ffffffff9f195ab1>] bus_for_each_dev+0x81/0xd0
> > > > > >      [<ffffffff9f197c62>] driver_attach+0x22/0x30
> > > > > >      [<ffffffff9f197354>] bus_add_driver+0x1b4/0x240
> > > > > >      [<ffffffff9f19a0a2>] driver_register+0x62/0x120
> > > > > >
> > > > > > There are currently 84 wmi_dev_probe leaks, sized mostly 64 bytes, and
> > > > > > one 96 and two 192 bytes.
> > > > > >
> > > > > > I also cannot figure out the mechanism by which current_value_show()
> > > > > > is called, when it is static?
> > > > > >
> > > > > > Any idea?
> > > > > >
> > > > > > Thanks.
> > > > > >
> > > > > > Best regards,
> > > > > > Mirsad
> > > > > Can you tell me how many BIOS settings think-lmi provides on your machine? Because according to the stacktrace,
> > > > > the other place where the leak could have occurred is inside tlmi_analyze(), which calls tlmi_setting().
> > > >
> > > > Yes, Sir!
> > > >
> > > > I think these could be the ones you need (totaling 83, which is close to 82 systemd-udevd leaks):
> > > >
> > > > [root@pc-mtodorov marvin]# ls -l /sys/devices/virtual/firmware-attributes/thinklmi/attributes | grep ^d
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 AfterPowerLoss
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 AlarmDate(MM\DD\YYYY)
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 AlarmDayofWeek
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 AlarmTime(HH:MM:SS)
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 ASPMSupport
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 AutomaticBootSequence
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 BIOSPasswordAtBootDeviceList
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 BIOSPasswordAtReboot
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 BIOSPasswordAtUnattendedBoot
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 BootMode
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 BootPriority
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 BootUpNum-LockStatus
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 C1ESupport
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 CardReader
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 ClearTCGSecurityFeature
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 ComputraceModuleActivation
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 ConfigurationChangeDetection
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 ConfigureSATAas
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 CoreMulti-Processing
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 CoverTamperDetected
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 CSM
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 CStateSupport
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 DeviceGuard
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 DustShieldAlert
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 EISTSupport
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 EnhancedPowerSavingMode
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 ErrorBootSequence
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 Friday
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 FrontUSBPorts
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 HardDiskPre-delay
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 Intel(R)SGXControl
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 InternalSpeaker
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 Monday
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 OnboardAudioController
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 OnboardEthernetController
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 OptionKeysDisplay
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 OptionKeysDisplayStyle
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 OSOptimizedDefaults
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 PasswordCountExceededError
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 PCIe16xSlotSpeed
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 PCIe1xSlot1Speed
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 PrimaryBootSequence
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 PXEIPV4NetworkStack
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 PXEIPV6NetworkStack
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 PXEOptionROM
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 RearUSBPorts
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 RequireAdmin.Pass.whenFlashing
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 RequireHDPonSystemBoot
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 SATAController
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 SATADrive1
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 SATADrive2
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 Saturday
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 SecureBoot
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 SecureRollBackPrevention
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 SecurityChip
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 SelectActiveVideo
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 SerialPort1Address
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 SmartUSBProtection
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 StartupDeviceMenuPrompt
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 StartupSequence
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 Sunday
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 Thursday
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 Tuesday
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 TurboMode
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 USBBIOSSupport
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 USBEnumerationDelay
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 USBPort1
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 USBPort2
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 USBPort3
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 USBPort4
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 USBPort5
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 USBPort6
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 USBPort7
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 USBPort8
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 USBPortAccess
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 UserDefinedAlarmTime(HH:MM:SS)
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 VirtualizationTechnology
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 VTdFeature
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 WakefromSerialPortRing
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 WakeOnLAN
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 WakeUponAlarm
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 Wednesday
> > > > drwxr-xr-x 2 root root    0 Mar 29 08:24 WindowsUEFIFirmwareUpdate
> > > > [root@pc-mtodorov marvin]# ls -l /sys/devices/virtual/firmware-attributes/thinklmi/attributes | grep ^d | wc -l
> > > > 83
> > > > [root@pc-mtodorov marvin]#
> > > >
> > > > > However, i have no idea on how *info is somehow leaked, it has to happen inside the for-loop tween the call
> > > > > to tlmi_setting() and strreplace(), because otherwise the strings would not contain the "/" character.
> > > >
> > > > I see. It is the line 1404.
> > > >
> > > > > Can you check if the problem is somehow solved by applying the following commit from the platform-drivers-x86
> > > > > for-next branch:
> > > > > da62908efe80 ("platform/x86: think-lmi: Properly interpret return value of tlmi_setting")
> > > >
> > > > It could possibly be that. But I do not recall seeing these messages in 6.3-rc3 ...
> > > >
> > > > ...
> > > >
> > > > Unfortunately, the build with Thomas' patch you referred to did not work:
> > > >
> > > > unreferenced object 0xffff9dff4d28bbc8 (size 192):
> > > >     comm "systemd-udevd", pid 769, jiffies 4294897473 (age 85.700s)
> > > >     hex dump (first 32 bytes):
> > > >       50 72 69 6d 61 72 79 42 6f 6f 74 53 65 71 75 65  PrimaryBootSeque
> > > >       6e 63 65 2c 4d 2e 32 20 44 72 69 76 65 20 31 3a  nce,M.2 Drive 1:
> > > >     backtrace:
> > > >       [<ffffffffa48fb26c>] slab_post_alloc_hook+0x8c/0x3e0
> > > >       [<ffffffffa4902b49>] __kmem_cache_alloc_node+0x1d9/0x2a0
> > > >       [<ffffffffa48773c9>] __kmalloc_node_track_caller+0x59/0x180
> > > >       [<ffffffffa4866a1a>] kstrdup+0x3a/0x70
> > > >       [<ffffffffc0c7f9aa>] tlmi_extract_output_string.isra.0+0x2a/0x60 [think_lmi]
> > > >       [<ffffffffc0c7fb64>] tlmi_setting.constprop.4+0x54/0x90 [think_lmi]
> > > >       [<ffffffffc0c802c1>] tlmi_probe+0x591/0xba0 [think_lmi]
> > > >       [<ffffffffc03c9c53>] wmi_dev_probe+0x163/0x230 [wmi]
> > > >       [<ffffffffa4f987eb>] really_probe+0x17b/0x3d0
> > > >       [<ffffffffa4f98ad4>] __driver_probe_device+0x84/0x190
> > > >       [<ffffffffa4f98c14>] driver_probe_device+0x24/0xc0
> > > >       [<ffffffffa4f98ed2>] __driver_attach+0xc2/0x190
> > > >       [<ffffffffa4f95ab1>] bus_for_each_dev+0x81/0xd0
> > > >       [<ffffffffa4f97c62>] driver_attach+0x22/0x30
> > > >       [<ffffffffa4f97354>] bus_add_driver+0x1b4/0x240
> > > >       [<ffffffffa4f9a0a2>] driver_register+0x62/0x120
> > > > unreferenced object 0xffff9dff4d28a008 (size 192):
> > > >     comm "systemd-udevd", pid 769, jiffies 4294897517 (age 85.540s)
> > > >     hex dump (first 32 bytes):
> > > >       45 72 72 6f 72 42 6f 6f 74 53 65 71 75 65 6e 63  ErrorBootSequenc
> > > >       65 2c 4e 65 74 77 6f 72 6b 20 31 3a 4d 2e 32 20  e,Network 1:M.2
> > > >     backtrace:
> > > >       [<ffffffffa48fb26c>] slab_post_alloc_hook+0x8c/0x3e0
> > > >       [<ffffffffa4902b49>] __kmem_cache_alloc_node+0x1d9/0x2a0
> > > >       [<ffffffffa48773c9>] __kmalloc_node_track_caller+0x59/0x180
> > > >       [<ffffffffa4866a1a>] kstrdup+0x3a/0x70
> > > >       [<ffffffffc0c7f9aa>] tlmi_extract_output_string.isra.0+0x2a/0x60 [think_lmi]
> > > >       [<ffffffffc0c7fb64>] tlmi_setting.constprop.4+0x54/0x90 [think_lmi]
> > > >       [<ffffffffc0c802c1>] tlmi_probe+0x591/0xba0 [think_lmi]
> > > >       [<ffffffffc03c9c53>] wmi_dev_probe+0x163/0x230 [wmi]
> > > >       [<ffffffffa4f987eb>] really_probe+0x17b/0x3d0
> > > >       [<ffffffffa4f98ad4>] __driver_probe_device+0x84/0x190
> > > >       [<ffffffffa4f98c14>] driver_probe_device+0x24/0xc0
> > > >       [<ffffffffa4f98ed2>] __driver_attach+0xc2/0x190
> > > >       [<ffffffffa4f95ab1>] bus_for_each_dev+0x81/0xd0
> > > >       [<ffffffffa4f97c62>] driver_attach+0x22/0x30
> > > >       [<ffffffffa4f97354>] bus_add_driver+0x1b4/0x240
> > > >       [<ffffffffa4f9a0a2>] driver_register+0x62/0x120
> > > > [root@pc-mtodorov marvin]# uname -rms
> > > > Linux 6.3.0-rc4-armin+tw-patch-00025-g3a93e40326c8-dirty x86_64
> > > > [root@pc-mtodorov marvin]#
> > > >
> > > > What was applied is:
> > > >
> > > > mtodorov@domac:~/linux/kernel/linux_torvalds$ git diff
> > > > diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
> > > > index c816646eb661..9a3015f43aaf 100644
> > > > --- a/drivers/platform/x86/think-lmi.c
> > > > +++ b/drivers/platform/x86/think-lmi.c
> > > > @@ -929,8 +929,10 @@ 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))
> > > > +       if (!value || value == item || !strlen(value + 1)) {
> > > > +               kfree(item);
> > > >                   return -EINVAL;
> > > > +       }
> > > >
> > > >           ret = sysfs_emit(buf, "%s\n", value + 1);
> > > >           kfree(item);
> > > > @@ -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;
> > > >
> > > >
> > > > > Also current_value_show() is used by attr_current_val, the __ATTR_RW_MODE() macro arranges for that.
> > > >
> > > > Thanks.
> > > >
> > > > In this build:
> > > >
> > > > [root@pc-mtodorov marvin]# uname -rms
> > > > Linux 6.3.0-rc34tests-00001-g6981739a967c x86_64
> > > > [root@pc-mtodorov marvin]#
> > > >
> > > > ... the bug isn't present, so it might be something added recently:
> > > >
> > > > commit 8a02d70679fc1c434401863333c8ea7dbf201494
> > > > Author: Mark Pearson <mpearson-lenovo@xxxxxxxxx>
> > > > Date:   Sun Mar 19 20:32:21 2023 -0400
> > > >
> > > >       platform/x86: think-lmi: Add possible_values for ThinkStation
> > > >
> > > > commit cf337f27f3bfc4aeab4954c468239fd6233c7638
> > > > Author: Mark Pearson <mpearson-lenovo@xxxxxxxxx>
> > > > Date:   Sun Mar 19 20:32:20 2023 -0400
> > > >
> > > >       platform/x86: think-lmi: only display possible_values if available
> > > >
> > > > commit 45e21289bfc6e257885514790a8a8887da822d40
> > > > Author: Mark Pearson <mpearson-lenovo@xxxxxxxxx>
> > > > Date:   Sun Mar 19 20:32:19 2023 -0400
> > > >
> > > >       platform/x86: think-lmi: use correct possible_values delimiters
> > > >
> > > > commit 583329dcf22e568a328a944f20427ccfc95dce01
> > > > Author: Mark Pearson <mpearson-lenovo@xxxxxxxxx>
> > > > Date:   Sun Mar 19 20:32:18 2023 -0400
> > > >
> > > >       platform/x86: think-lmi: add missing type attribute
> > > >
> > > > I have CC:-ed the author of the commits.
> > > >
> > > > I can try bisect, but only after my day job.
> > > I seem to have been right about the culprit commit.
> > > Here is the bisect log:
> > > mtodorov@domac:~/linux/kernel/linux_torvalds$ git bisect log
> > > git bisect start '--' './drivers/platform/x86'
> > > # good: [caa0708a81d6a2217c942959ef40d515ec1d3108] bootconfig: Change message if no bootconfig with CONFIG_BOOT_CONFIG_FORCE=y
> > > git bisect good caa0708a81d6a2217c942959ef40d515ec1d3108
> > > # bad: [8a02d70679fc1c434401863333c8ea7dbf201494] platform/x86: think-lmi: Add possible_values for ThinkStation
> > > git bisect bad 8a02d70679fc1c434401863333c8ea7dbf201494
> > > # good: [1a0009abfa7893b9cfcd3884658af1cbee6b26ce] platform: mellanox: mlx-platform: Initialize shift variable to 0
> > > git bisect good 1a0009abfa7893b9cfcd3884658af1cbee6b26ce
> > > # good: [b7c994f8c35e916e27c60803bb21457bc1373500] platform/x86 (gigabyte-wmi): Add support for A320M-S2H V2
> > > git bisect good b7c994f8c35e916e27c60803bb21457bc1373500
> > > # good: [45e21289bfc6e257885514790a8a8887da822d40] platform/x86: think-lmi: use correct possible_values delimiters
> > > git bisect good 45e21289bfc6e257885514790a8a8887da822d40
> > > # good: [cf337f27f3bfc4aeab4954c468239fd6233c7638] platform/x86: think-lmi: only display possible_values if available
> > > git bisect good cf337f27f3bfc4aeab4954c468239fd6233c7638
> > > # first bad commit: [8a02d70679fc1c434401863333c8ea7dbf201494] platform/x86: think-lmi: Add possible_values for ThinkStation
> > > mtodorov@domac:~/linux/kernel/linux_torvalds$
> > > Please see below.
> > > Apparently, this commit broke something on my Lenovo box:
> > > diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
> > > index e190fec26021..3f0641360251 100644
> > > --- a/drivers/platform/x86/think-lmi.c
> > > +++ b/drivers/platform/x86/think-lmi.c
> > > @@ -941,9 +941,6 @@ static ssize_t possible_values_show(struct kobject *kobj, struct kobj_attribute
> > >   {
> > >          struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);
> > > -       if (!tlmi_priv.can_get_bios_selections)
> > > -               return -EOPNOTSUPP;
> > > -
> > >          return sysfs_emit(buf, "%s\n", setting->possible_values);
> > >   }
> > > @@ -1052,6 +1049,18 @@ static struct kobj_attribute attr_current_val = __ATTR_RW_MODE(current_value, 06
> > >   static struct kobj_attribute attr_type = __ATTR_RO(type);
> > > +static umode_t attr_is_visible(struct kobject *kobj,
> > > +                                            struct attribute *attr, int n)
> > > +{
> > > +       struct tlmi_attr_setting *setting = to_tlmi_attr_setting(kobj);
> > > +
> > > +       /* We don't want to display possible_values attributes if not available */
> > > +       if ((attr == &attr_possible_values.attr) && (!setting->possible_values))
> > > +               return 0;
> > > +
> > > +       return attr->mode;
> > > +}
> > > +
> > >   static struct attribute *tlmi_attrs[] = {
> > >          &attr_displ_name.attr,
> > >          &attr_current_val.attr,
> > > @@ -1061,6 +1070,7 @@ static struct attribute *tlmi_attrs[] = {
> > >   };
> > >   static const struct attribute_group tlmi_attr_group = {
> > > +       .is_visible = attr_is_visible,
> > >          .attrs = tlmi_attrs,
> > >   };
> > > Hope this helps narrow down the problem.
> > > Best regards,
> > > Mirsad
> > > Why aren't you looking at the wmi.c driver?  That should be
> > > > > > > …
> >
> > mtodorov@domac:~/linux/kernel/linux_torvalds$ git bisect log
> > git bisect start '--' './drivers/platform/x86'
> > # good: [caa0708a81d6a2217c942959ef40d515ec1d3108] bootconfig: Change message if no bootconfig with CONFIG_BOOT_CONFIG_FORCE=y
> > git bisect good caa0708a81d6a2217c942959ef40d515ec1d3108
> > # bad: [8a02d70679fc1c434401863333c8ea7dbf201494] platform/x86: think-lmi: Add possible_values for ThinkStation
> > git bisect bad 8a02d70679fc1c434401863333c8ea7dbf201494
> > # good: [1a0009abfa7893b9cfcd3884658af1cbee6b26ce] platform: mellanox: mlx-platform: Initialize shift variable to 0
> > git bisect good 1a0009abfa7893b9cfcd3884658af1cbee6b26ce
> > # good: [b7c994f8c35e916e27c60803bb21457bc1373500] platform/x86 (gigabyte-wmi): Add support for A320M-S2H V2
> > git bisect good b7c994f8c35e916e27c60803bb21457bc1373500
> > # good: [45e21289bfc6e257885514790a8a8887da822d40] platform/x86: think-lmi: use correct possible_values delimiters
> > git bisect good 45e21289bfc6e257885514790a8a8887da822d40
> > # good: [cf337f27f3bfc4aeab4954c468239fd6233c7638] platform/x86: think-lmi: only display possible_values if available
> > git bisect good cf337f27f3bfc4aeab4954c468239fd6233c7638
> > # first bad commit: [8a02d70679fc1c434401863333c8ea7dbf201494] platform/x86: think-lmi: Add possible_values for ThinkStation
> > mtodorov@domac:~/linux/kernel/linux_torvalds$
> >
> > So the commit that triggered the bug on the Lenovo desktop box was:
> >
> > diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
> > index 3f0641360251..c816646eb661 100644
> > --- a/drivers/platform/x86/think-lmi.c
> > +++ b/drivers/platform/x86/think-lmi.c
> > @@ -1450,6 +1450,26 @@ static int tlmi_analyze(void)
> >                           if (ret || !setting->possible_values)
> >                                   pr_info("Error retrieving possible values for %d : %s\n",
> >                                                   i, setting->display_name);
> > +               } else {
> > +                       /*
> > +                        * Older Thinkstations don't support the bios_selections API.
> > +                        * Instead they store this as a [Optional:Option1,Option2] section of the
> > +                        * name string.
> > +                        * Try and pull that out if it's available.
> > +                        */
> > +                       char *item, *optstart, *optend;
> > +
> > +                       if (!tlmi_setting(setting->index, &item, LENOVO_BIOS_SETTING_GUID)) {
> > +                               optstart = strstr(item, "[Optional:");
> > +                               if (optstart) {
> > +                                       optstart += strlen("[Optional:");
> > +                                       optend = strstr(optstart, "]");
> > +                                       if (optend)
> > +                                               setting->possible_values =
> > +                                                       kstrndup(optstart, optend - optstart,
> > +                                                                       GFP_KERNEL);
>
> I guess item needs to be freed here.
>
> (Next week I have access to my Lenovo machine again.
> I'll look at it then if it's not solved.)

Yes, thank you, Thomas, I am just building with the following patch:

diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
index c816646eb661..e8c28f4f5a71 100644
--- a/drivers/platform/x86/think-lmi.c
+++ b/drivers/platform/x86/think-lmi.c
@@ -1469,6 +1469,7 @@ static int tlmi_analyze(void)
                                                        kstrndup(optstart, optend - optstart,
                                                                        GFP_KERNEL);
                                }
+                               kfree(item);
                        }
                }
                /*

You were 3 minutes faster ;-)

The build with this patch is finished. Apparently, that was the culprit, for now
I get:

[root@pc-mtodorov marvin]# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff8fa859c89f10 (size 16):
  comm "kworker/u12:5", pid 369, jiffies 4294897651 (age 91.724s)
  hex dump (first 16 bytes):
    6d 65 6d 73 74 69 63 6b 30 00 cc cc cc cc cc cc  memstick0.......
  backtrace:
    [<ffffffff8ef0a8fc>] slab_post_alloc_hook+0x8c/0x3e0
    [<ffffffff8ef12289>] __kmem_cache_alloc_node+0x1d9/0x2a0
    [<ffffffff8ee85719>] __kmalloc_node_track_caller+0x59/0x1f0
    [<ffffffff8ee749da>] kstrdup+0x3a/0x70
    [<ffffffff8ee74a4c>] kstrdup_const+0x2c/0x40
    [<ffffffff8f2c0a3c>] kvasprintf_const+0x7c/0xb0
    [<ffffffff8fc5f427>] kobject_set_name_vargs+0x27/0xa0
    [<ffffffff8f5a79f7>] dev_set_name+0x57/0x80
    [<ffffffffc0cd2f0f>] memstick_check+0x10f/0x3b0 [memstick]
    [<ffffffff8ebd41d0>] process_one_work+0x250/0x600
    [<ffffffff8ebd45d8>] worker_thread+0x48/0x3a0
    [<ffffffff8ebdfdef>] kthread+0x10f/0x140
    [<ffffffff8ea03089>] ret_from_fork+0x29/0x50
unreferenced object 0xffff8fa859c89d90 (size 16):
  comm "kworker/u12:5", pid 369, jiffies 4294897656 (age 91.704s)
  hex dump (first 16 bytes):
    6d 65 6d 73 74 69 63 6b 30 00 cc cc cc cc cc cc  memstick0.......
  backtrace:
    [<ffffffff8ef0a8fc>] slab_post_alloc_hook+0x8c/0x3e0
    [<ffffffff8ef12289>] __kmem_cache_alloc_node+0x1d9/0x2a0
    [<ffffffff8ee85719>] __kmalloc_node_track_caller+0x59/0x1f0
    [<ffffffff8ee749da>] kstrdup+0x3a/0x70
    [<ffffffff8ee74a4c>] kstrdup_const+0x2c/0x40
    [<ffffffff8f2c0a3c>] kvasprintf_const+0x7c/0xb0
    [<ffffffff8fc5f427>] kobject_set_name_vargs+0x27/0xa0
    [<ffffffff8f5a79f7>] dev_set_name+0x57/0x80
    [<ffffffffc0cd2f0f>] memstick_check+0x10f/0x3b0 [memstick]
    [<ffffffff8ebd41d0>] process_one_work+0x250/0x600
    [<ffffffff8ebd45d8>] worker_thread+0x48/0x3a0
    [<ffffffff8ebdfdef>] kthread+0x10f/0x140
    [<ffffffff8ea03089>] ret_from_fork+0x29/0x50
[root@pc-mtodorov marvin]#

So, the "tlmi_setting" memory leak appears to be fixed by this diff.

The next step is to add Armin-suggested patch:

diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
index c816646eb661..1e77ecb0cba8 100644
--- a/drivers/platform/x86/think-lmi.c
+++ b/drivers/platform/x86/think-lmi.c
@@ -929,8 +929,10 @@ 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))
+       if (!value || value == item || !strlen(value + 1)) {
+               kfree(item);
                return -EINVAL;
+       }

        ret = sysfs_emit(buf, "%s\n", value + 1);
        kfree(item);

and Thomas' correction for the return type of the tlmi_setting() function:

diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c
index 86b33b74519be..c924e9e4a6a5b 100644
--- a/drivers/platform/x86/think-lmi.c
+++ b/drivers/platform/x86/think-lmi.c
@@ -1353,7 +1353,6 @@ 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) &&
@@ -1390,8 +1389,8 @@ 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;

A build on top of 6.3-rc4+ fcd476ea6a88 commit is on the way, with all three included.

Best regards,
Mirsad

--
Mirsad Todorovac
System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb
Republic of Croatia, the European Union

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