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| author | Jinjiang Tu <tujinjiang@huawei.com> | 2024-11-13 16:32:35 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-11-22 15:37:30 +0100 |
| commit | 6addb2d9501ec866d7b3a3b4e665307c437e9be2 (patch) | |
| tree | 19ca5db3a5f3c45d51f8dffd3dbe1d0e39ec3fb6 /mm | |
| parent | 69556613d99ba5d848a5fba5d04355a061de5219 (diff) | |
| download | linux-6addb2d9501ec866d7b3a3b4e665307c437e9be2.tar.gz linux-6addb2d9501ec866d7b3a3b4e665307c437e9be2.tar.bz2 linux-6addb2d9501ec866d7b3a3b4e665307c437e9be2.zip | |
mm: fix NULL pointer dereference in alloc_pages_bulk_noprof
commit 8ce41b0f9d77cca074df25afd39b86e2ee3aa68e upstream.
We triggered a NULL pointer dereference for ac.preferred_zoneref->zone in
alloc_pages_bulk_noprof() when the task is migrated between cpusets.
When cpuset is enabled, in prepare_alloc_pages(), ac->nodemask may be
¤t->mems_allowed. when first_zones_zonelist() is called to find
preferred_zoneref, the ac->nodemask may be modified concurrently if the
task is migrated between different cpusets. Assuming we have 2 NUMA Node,
when traversing Node1 in ac->zonelist, the nodemask is 2, and when
traversing Node2 in ac->zonelist, the nodemask is 1. As a result, the
ac->preferred_zoneref points to NULL zone.
In alloc_pages_bulk_noprof(), for_each_zone_zonelist_nodemask() finds a
allowable zone and calls zonelist_node_idx(ac.preferred_zoneref), leading
to NULL pointer dereference.
__alloc_pages_noprof() fixes this issue by checking NULL pointer in commit
ea57485af8f4 ("mm, page_alloc: fix check for NULL preferred_zone") and
commit df76cee6bbeb ("mm, page_alloc: remove redundant checks from alloc
fastpath").
To fix it, check NULL pointer for preferred_zoneref->zone.
Link: https://lkml.kernel.org/r/20241113083235.166798-1-tujinjiang@huawei.com
Fixes: 387ba26fb1cb ("mm/page_alloc: add a bulk page allocator")
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Lobakin <alobakin@pm.me>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page_alloc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b87b350b2f40..58a3f70eb39b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5457,7 +5457,8 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, gfp = alloc_gfp; /* Find an allowed local zone that meets the low watermark. */ - for_each_zone_zonelist_nodemask(zone, z, ac.zonelist, ac.highest_zoneidx, ac.nodemask) { + z = ac.preferred_zoneref; + for_next_zone_zonelist_nodemask(zone, z, ac.highest_zoneidx, ac.nodemask) { unsigned long mark; if (cpusets_enabled() && (alloc_flags & ALLOC_CPUSET) && |