Re: Subject: [PATCH v2] slab: kmalloc_size_roundup() must not return 0 for non-zero size

[Vlastimil Babka]

On 9/11/23 18:38, David Laight wrote:
>> >> So perhaps the best would be to return size for c == NULL, but also do a
>> >> WARN_ONCE?
>> >
>> > That would add a real function call to an otherwise leaf function
>> > and almost certainly require the compiler create a stack frame.
>> 
>> Hm I thought WARN is done by tripping on undefined instruction like BUG
>> these days. Also any code that accepts the call to kmalloc_size_roundup
>> probably could accept that too.
> 
> It's probably just worth removing the c == NULL check and
> assuming there won't be any fallout.
> The NULL pointer deref is an easy to debug as anything else.
> 
> If it gets called in any early init code it'll soon show up.
 
Good point, early crash should be ok.
So how about this with my tweaks, looks ok? I'll put it in -next and
send with another hotfix to 6.6 next week.
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