Re: [PATCH v2 1/2] maple_tree: Disable mas_wr_append() when other readers are possible

[Linux regression tracking #update (Thorsten Leemhuis)]

On 11.09.23 14:27, Linux regression tracking #adding (Thorsten Leemhuis)
wrote:
> On 29.08.23 18:42, Geert Uytterhoeven wrote:
>>
>> On Fri, 18 Aug 2023, Liam R. Howlett wrote:
>>> The current implementation of append may cause duplicate data and/or
>>> incorrect ranges to be returned to a reader during an update.  Although
>>> this has not been reported or seen, disable the append write operation
>>> while the tree is in rcu mode out of an abundance of caution.
>>>
>>> During the analysis of the mas_next_slot() the following was
>>> artificially created by separating the writer and reader code:
>> [...]
>> Thanks for your patch, which is now commit cfeb6ae8bcb96ccf
>> ("maple_tree: disable mas_wr_append() when other readers are
>> possible") in v6.5, and is being backported to stable.
>>
>> On Renesas RZ/A1 and RZ/A2 (single-core Cortex-A9), this causes the
>> following warning:
>>> […]
>> Reverting this commit fixes the issue.

#regzbot fix: cff9b2332ab762
#regzbot ignore-activity

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
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