Re: [PATCH] cxl/core: fix test_bit misuse with CXL_DECODER_F_ bitmask flags
From: Dave Jiang
Date: Mon Feb 23 2026 - 13:05:13 EST
On 2/23/26 10:45 AM, Gregory Price wrote:
> On Mon, Feb 23, 2026 at 11:33:13AM -0600, Cheatham, Benjamin wrote:
>> On 2/20/2026 8:18 PM, Gregory Price wrote:
>>> CXL_DECODER_F_LOCK (BIT(4) = 16) and CXL_DECODER_F_NORMALIZED_ADDRESSING
>>> (BIT(6) = 64) are bit masks, but three call sites pass them to test_bit()
>>> which expects a bit number.
>>>
>>> Replace test_bit() with direct bitmask tests, consistent with every other
>>> use of these flags.
>>>
>>> Fixes: 2230c4bdc412 ("cxl: Add handling of locked CXL decoder")
>>> Signed-off-by: Gregory Price <gourry@xxxxxxxxxx>
>>
>> Alison sent out a patch [1] two weeks ago for this. I suspect you found this bug
>> independently, so I figured I should point it out. Otherwise, I would add a Reported-by (or some
>> other tag) with her name.
>>
>> Thanks,
>> Ben
>>
>> [1]: https://lore.kernel.org/linux-cxl/20260206181404.1025991-1-alison.schofield@xxxxxxxxx/
>
> Ah, yeah, missed this, and did find independently when testing unbinds.
>
> Wasn't on cxl/next so I thought it hadn't been found yet.
Yeah waiting on 7.0-rc1 for cxl/fixes. I also asked her to split the patches into 2 fixes. But if you don't mind go add your review tag that'd be great! :)
>
> Cool, thanks!
> ~Gregory