Re: [BUG?] unchecked MSR access error: WRMSR to 0x19c

[Borislav Petkov]

CCing more appropiate people and quoting the whole mail...

On Wed, Apr 05, 2023 at 11:14:45PM +0100, Rui Salvaterra wrote:
> Hi, everyone,
> 
> I have a Haswell (Core i7-4770R) machine running Linux 6.3-rc5 on
> which, after a while under load (say, compiling the kernel), I get
> this trace…
> 
> [  832.549630] unchecked MSR access error: WRMSR to 0x19c (tried to
> write 0x000000000000aaa8) at rIP: 0xffffffff816f66a6
> (throttle_active_work+0xa6/0x1d0)
> [  832.549652] Call Trace:
> [  832.549654]  <TASK>
> [  832.549655]  process_one_work+0x1ab/0x300
> [  832.549661]  worker_thread+0x4b/0x340
> [  832.549664]  ? process_one_work+0x300/0x300
> [  832.549676]  kthread+0xac/0xc0
> [  832.549679]  ? kthread_exit+0x20/0x20
> [  832.549682]  ret_from_fork+0x1f/0x30
> [  832.549693]  </TASK>
> 
> … after which I get these from time to time in dmesg.
> 
> [  836.709562] CPU7: Core temperature is above threshold, cpu clock is
> throttled (total events = 219)
> [  836.709569] CPU3: Core temperature is above threshold, cpu clock is
> throttled (total events = 219)
> [ 1272.792138] CPU2: Core temperature is above threshold, cpu clock is
> throttled (total events = 1)
> [ 1272.792156] CPU6: Core temperature is above threshold, cpu clock is
> throttled (total events = 1)
> 
> This is the microcode revision on the CPU.
> 
> [    0.000000] microcode: updated early: 0xe -> 0x1c, date = 2019-11-12
> 
> Note that I have the exact same issue on an Ivy Bridge (Core
> i7-3720QM) machine, but not on an Ivy Bridge laptop (Celeron 1007U).
> Maybe this is a legitimate warning, but please note that I've
> thorughly cleaned the machines before retesting to see if, by
> coincidence, I had any airway/cooling issues. The fact that it started
> happening recently (since Linux 6.1, I believe), and the fact that
> running stress-ng --cpu 16 before the unchecked WRMSR error happens
> doesn't cause any thermal throttling events, lead me to believe this
> is possibly some unintended oversight.
> 
> Please let me know if you need any additional information (.config, or
> anything else).
> 
> Thanks in advance,
> Rui

-- 
Regards/Gruss,
    Boris.

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