Re: [PATCH] platform/x86: think-lmi: Fix "Call Trace" error warning

[Ilpo Järvinen]

On Wed, 8 Jul 2026, Gou Tongchen wrote:
> On 7/7/26 21:31, Mark Pearson wrote:
> > On Tue, Jul 7, 2026, at 5:15 AM, goutongchen@xxxxxxxxxxxxx wrote:
> > > From: goutongchen <goutongchen@xxxxxxxxxxxxx>
> > > 
> > > The maximum BIOS password length returned by the Lenovo platform BIOS/WMI
> > > exceeded the size assumed by the think_lmi driver's internal static
> > > buffer, causing the driver to trigger a WARN_ON() during self-checks.
> > > 
> > > Increase TLMI_PWD_BUFSIZE from 128 to 256 to eliminate the recurring
> > > Call Trace warnings.
> > > 
> > > Here is the kernel warning triggered by the bug:
> > > 
> > >    kernel: WARNING: CPU: 4 PID: 665 at
> > > drivers/platform/x86/think-lmi.c:326
> > >    kernel:        tlmi_get_pwd_settings.constprop.0+0xe6/0x130 [think_lmi]
> > >    kernel: Call Trace:
> > >    kernel:  tlmi_analyze+0x31c/0x640 [think_lmi]
> > >    ...
> > > 
> > > Fixes: 651b57dd4087 ("platform/x86: Move Lenovo files into lenovo subdir")
> > Minor - but I don't think this is really the culprit :)
>
> Gou Tongchen - Because it was initially discovered on an older kernel version,
> the path hadn't been changed at that time.

Please try to find the commit past that. You can use e.g.

git annotate 651b57dd4087^

to start annotating from right before that commit.

> > > Signed-off-by: goutongchen <goutongchen@xxxxxxxxxxxxx>
> > > ---
> > >   drivers/platform/x86/lenovo/think-lmi.h | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/platform/x86/lenovo/think-lmi.h
> > > b/drivers/platform/x86/lenovo/think-lmi.h
> > > index 017644323d46..d643cf3b81b0 100644
> > > --- a/drivers/platform/x86/lenovo/think-lmi.h
> > > +++ b/drivers/platform/x86/lenovo/think-lmi.h
> > > @@ -8,7 +8,7 @@
> > > 
> > >   #define TLMI_SETTINGS_COUNT  256
> > >   #define TLMI_SETTINGS_MAXLEN 512
> > > -#define TLMI_PWD_BUFSIZE     129
> > > +#define TLMI_PWD_BUFSIZE     256
> > >   #define TLMI_LANG_MAXLEN       4
> > >   #define TLMI_INDEX_MAX        32
> > > 
> > > -- 
> > > 2.20.1
> > Which platform are you seeing this on please? The maxlen for passwords from
> > the BIOS is supposed to be 128 so I'm intrigued as to where you're seeing
> > different. It maybe should be fixed in a platform BIOS?
> > 
> > Mark
> 
> The hardware platform is a Lenovo X7h with a Hygon 4 CPU. The specific
> model and BIOS version are as follows:
>
> kernel: DMI: KaiTian /LXKT-HG4M-X7, BIOS W0WKT1FA 11/18/2025

This kind of information should be in the changelog, but lets wait a bit 
if Mark wants to check this internally.

We'll probably need to make this change anyway to avoid triggering 
the WARN_ON() even if it would be fixed by some version of the BIOS.

> I found through kernel log printing that the BIOS returned a password
> length of 255, so I increased TLMI_PWD_BUFSIZE to 256.


-- 
 i.