This is a note to let you know that I've just added the patch titled
mm/vmalloc: fix page mapping if vm_area_alloc_pages() with high order fallback to order 0
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-vmalloc-fix-page-mapping-if-vm_area_alloc_pages-w.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 09369399e55a001e315d20eb951f822b702dc628
Author: Hailong Liu <hailong.liu@xxxxxxxx>
Date: Thu Aug 8 20:19:56 2024 +0800
mm/vmalloc: fix page mapping if vm_area_alloc_pages() with high order fallback to order 0
[ Upstream commit 61ebe5a747da649057c37be1c37eb934b4af79ca ]
The __vmap_pages_range_noflush() assumes its argument pages** contains
pages with the same page shift. However, since commit e9c3cda4d86e ("mm,
vmalloc: fix high order __GFP_NOFAIL allocations"), if gfp_flags includes
__GFP_NOFAIL with high order in vm_area_alloc_pages() and page allocation
failed for high order, the pages** may contain two different page shifts
(high order and order-0). This could lead __vmap_pages_range_noflush() to
perform incorrect mappings, potentially resulting in memory corruption.
Users might encounter this as follows (vmap_allow_huge = true, 2M is for
PMD_SIZE):
kvmalloc(2M, __GFP_NOFAIL|GFP_X)
__vmalloc_node_range_noprof(vm_flags=VM_ALLOW_HUGE_VMAP)
vm_area_alloc_pages(order=9) ---> order-9 allocation failed and fallback to order-0
vmap_pages_range()
vmap_pages_range_noflush()
__vmap_pages_range_noflush(page_shift = 21) ----> wrong mapping happens
We can remove the fallback code because if a high-order allocation fails,
__vmalloc_node_range_noprof() will retry with order-0. Therefore, it is
unnecessary to fallback to order-0 here. Therefore, fix this by removing
the fallback code.
Link: https://lkml.kernel.org/r/20240808122019.3361-1-hailong.liu@xxxxxxxx
Fixes: e9c3cda4d86e ("mm, vmalloc: fix high order __GFP_NOFAIL allocations")
Signed-off-by: Hailong Liu <hailong.liu@xxxxxxxx>
Reported-by: Tangquan Zheng <zhengtangquan@xxxxxxxx>
Reviewed-by: Baoquan He <bhe@xxxxxxxxxx>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Acked-by: Barry Song <baohua@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 078f6b53f8d50..732ff66d1b513 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3079,15 +3079,8 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
page = alloc_pages(alloc_gfp, order);
else
page = alloc_pages_node(nid, alloc_gfp, order);
- if (unlikely(!page)) {
- if (!nofail)
- break;
-
- /* fall back to the zero order allocations */
- alloc_gfp |= __GFP_NOFAIL;
- order = 0;
- continue;
- }
+ if (unlikely(!page))
+ break;
/*
* Higher order allocations must be able to be treated as
