From: Wei Yang <richard.weiyang@gmail.com>
Date: Tue, 16 Apr 2024 01:25:59 +0000 (+0000)
Subject: mm/sparse: guard the size of mem_section is power of 2
X-Git-Tag: v6.10-rc1~105^2~113
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=122ff80e12b3aa586d702b7fb651a99d443e7777;p=thirdparty%2Flinux.git

mm/sparse: guard the size of mem_section is power of 2

We usually have this check, while commit 2a3cb8baef71 ("mm/sparse: delete
old sparse_init and enable new one") missed to take it.

Link: https://lkml.kernel.org/r/20240416012559.4536-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: "Mike Rapoport (IBM)" <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/sparse.c b/mm/sparse.c
index 46e88549d1a6a..de40b2c734067 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -560,6 +560,8 @@ void __init sparse_init(void)
 	unsigned long pnum_end, pnum_begin, map_count = 1;
 	int nid_begin;
 
+	/* see include/linux/mmzone.h 'struct mem_section' definition */
+	BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section)));
 	memblocks_present();
 
 	pnum_begin = first_present_section_nr();