From d937fc3fb151b278a191d447ea7cf1df8b76616f Mon Sep 17 00:00:00 2001 From: Kamlesh Gurudasani Date: Thu, 22 Aug 2024 02:32:52 +0530 Subject: [PATCH] padata: Honor the caller's alignment in case of chunk_size 0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit 24cc57d8faaa4060fd58adf810b858fcfb71a02f ] In the case where we are forcing the ps.chunk_size to be at least 1, we are ignoring the caller's alignment. Move the forcing of ps.chunk_size to be at least 1 before rounding it up to caller's alignment, so that caller's alignment is honored. While at it, use max() to force the ps.chunk_size to be at least 1 to improve readability. Fixes: 6d45e1c948a8 ("padata: Fix possible divide-by-0 panic in padata_mt_helper()") Signed-off-by: Kamlesh Gurudasani Acked-by:  Waiman Long Acked-by: Daniel Jordan Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin --- kernel/padata.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/padata.c b/kernel/padata.c index 2a514cf83..41d5bf2fa 100755 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -516,9 +516,12 @@ void __init padata_do_multithreaded(struct padata_mt_job *job) * thread function. Load balance large jobs between threads by * increasing the number of chunks, guarantee at least the minimum * chunk size from the caller, and honor the caller's alignment. + * Ensure chunk_size is at least 1 to prevent divide-by-0 + * panic in padata_mt_helper(). */ ps.chunk_size = job->size / (ps.nworks * load_balance_factor); ps.chunk_size = max(ps.chunk_size, job->min_chunk); + ps.chunk_size = max(ps.chunk_size, 1ul); ps.chunk_size = roundup(ps.chunk_size, job->align); /*