Re: [PATCH 1/1] mm: sysctl: add panic_on_inconsistent_mm sysctl

[Vlastimil Babka]

On 1/30/20 8:28 PM, Kees Cook wrote:
> On Thu, Jan 30, 2020 at 03:44:50PM +0100, Vlastimil Babka wrote:
>> On 1/29/20 7:08 PM, Grzegorz Halat wrote:
>>> Memory management subsystem performs various checks at runtime,
>>> if an inconsistency is detected then such event is being logged and kernel
>>> continues to run. While debugging such problems it is helpful to collect
>>> memory dump as early as possible. Currently, there is no easy way to panic
>>> kernel when such error is detected.
>>>
>>> It was proposed[1] to panic the kernel if panic_on_oops is set but this
>>> approach was not accepted. One of alternative proposals was introduction of
>>> a new sysctl.
>>>
>>> Add a new sysctl - panic_on_inconsistent_mm. If the sysctl is set then the
>>> kernel will be crashed when an inconsistency is detected by memory
>>> management. This currently means panic when bad page or bad PTE
>>> is detected(this may be extended to other places in MM).
>>
>> I wonder, should enabling the sysctl also effectively convert VM_WARN...
>> to VM_BUG... ?
> 
> There is already panic_on_warn sysctl... wouldn't that be sufficient?

True, forgot about it. Thanks.