On Sat, Aug 10, 2024 at 09:30:25PM -0400, Waiman Long wrote: > > On 8/10/24 00:05, Herbert Xu wrote: > > Waiman Long <longman@xxxxxxxxxx> wrote: > > > diff --git a/kernel/padata.c b/kernel/padata.c > > > index 53f4bc912712..0fa6c2895460 100644 > > > --- a/kernel/padata.c > > > +++ b/kernel/padata.c > > > @@ -517,6 +517,13 @@ void __init padata_do_multithreaded(struct padata_mt_job *job) > > > ps.chunk_size = max(ps.chunk_size, job->min_chunk); > > > ps.chunk_size = roundup(ps.chunk_size, job->align); > > > > > > + /* > > > + * chunk_size can be 0 if the caller sets min_chunk to 0. So force it > > > + * to at least 1 to prevent divide-by-0 panic in padata_mt_helper().` > > > + */ > > > + if (!ps.chunk_size) > > > + ps.chunk_size = 1U; > > Perhaps change the first ps.chunk_size assignment to use DIV_ROUND_UP > > instead? > > I think DIV_ROUND_UP() will exactly the same problem that if chunk_size is > 0, you still got a 0 result. round_up() only if the 2nd argument is a power > of 2 while with DIV_ROUND_UP(), the second argument can be any number except > 0. Unless I'm missing something chunk_size cannot be zero before the division because that's the first thing we check upon entry into this function. Cheers, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
