Re: [PATCH v2 12/32] mm/vmalloc: vmalloc_to_page() use pte_offset_kernel()

Linux regression tracking #adding (Thorsten Leemhuis)
2023-07-11T14:49:03Z

[CCing the regression list, as it should be in the loop for regressions:
https://docs.kernel.org/admin-guide/reporting-regressions.html]

[TLDR: I'm adding this report to the list of tracked Linux kernel
regressions; the text you find below is based on a few templates
paragraphs you might have encountered already in similar form.
See link in footer if these mails annoy you.]

On 10.07.23 16:42, Mark Brown wrote:
> On Thu, Jun 08, 2023 at 06:21:41PM -0700, Hugh Dickins wrote:
>> vmalloc_to_page() was using pte_offset_map() (followed by pte_unmap()),
>> but it's intended for userspace page tables: prefer pte_offset_kernel().
>>
>> Signed-off-by: Hugh Dickins <hughd@google.com>
>> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
>
> Currently Linus' tree is reliably failing to boot on pine64plus, an
> arm64 SBC. Most other boards seem fine, though I am seeing some
> additional instability on Tritium which is another Allwinner platform,
> I've not dug into that yet and Tritium is generally less stable.
>
> We end up seeing NULL or otherwise bad pointer dereferences, the
> [...]
> # first bad commit: [0d1c81edc61e553ed7a5db18fb8074c8b78e1538] mm/vmalloc: vmalloc_to_page() use pte_offset_kernel()

Thanks for the report. To be sure the issue doesn't fall through the
cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression
tracking bot:

#regzbot ^introduced 0d1c81edc61e553ed7a5db18fb8074c8
#regzbot title mm/vmalloc: NULL or otherwise bad pointer dereferences on
ARM64
#regzbot ignore-activity

This isn't a regression? This issue or a fix for it are already
discussed somewhere else? It was fixed already? You want to clarify when
the regression started to happen? Or point out I got the title or
something else totally wrong? Then just reply and tell me -- ideally
while also telling regzbot about it, as explained by the page listed in
the footer of this mail.

Developers: When fixing the issue, remember to add 'Link:' tags pointing
to the report (the parent of this mail). See page linked in footer for
details.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
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