Re: [PATCH v15 00/23] Generic page walk and ptdump

[Qian Cai]

> On Dec 4, 2019, at 11:32 AM, Steven Price <Steven.Price@xxxxxxx> wrote:
> 
> I've bisected this problem and it's a merge conflict with:
> 
> ace88f1018b8 ("mm: pagewalk: Take the pagetable lock in walk_pte_range()")

Sigh, how does that commit end up merging in the mainline without going through Andrewâs tree and missed all the linux-next testing? It was merged into the mainline Oct 4th?

> Reverting that commit "fixes" the problem. That commit adds a call to
> pte_offset_map_lock(), however that isn't necessarily safe when
> considering an "unusual" mapping in the kernel. Combined with my patch
> set this leads to the BUG when walking the kernel's page tables.
> 
> At this stage I think it's best if Andrew drops my series and I'll try
> to rework it on top -rc1 fixing up this conflict and the other x86
> 32-bit issue that has cropped up.