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mm/vmalloc: set area's page_order after allocation succeeds

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__vmalloc_area_node() calls set_vm_area_page_order() to set area's
page_order before actually allocating pages to populate the area.

If allocation of large pages in HUGE_VMAP case fails midway, this leaves
the area with elevated page_order throughout the cleanup path.

There is no actual issue with this because the only place that currently
relies on area->page_order on the cleanup path is the loop calculating the
direct map alias range in vm_reset_perms() and it anyway skips unpopulated
pages.

But having set_vm_area_page_order() in the middle of __vmalloc_area_node()
makes things very obscure, hard to reason about and error prone against
future changes of the cleanup path.

Move the call to set_vm_area_page_order() just before the successful
return from __vmalloc_area_node() where page order is guaranteed.

While on it, initialize local page_order variable with its declaration.

Link: https://lore.kernel.org/20260903-execmem-set-vm-perms-v0-2-v3-2-949b64a9f755@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
This commit is contained in:
Mike Rapoport (Microsoft) 2026-09-03 12:28:28 +03:00 committed by Andrew Morton
parent be7dacb9c1
commit 40702f168a
1 changed files with 2 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
mm/vmalloc.c
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@ -3873,7 +3873,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
unsigned long size = get_vm_area_size(area);
unsigned long array_size;
unsigned long nr_small_pages = size >> PAGE_SHIFT;
unsigned int page_order;
unsigned int page_order = page_shift - PAGE_SHIFT;
unsigned int flags;
int ret;
@ -3901,9 +3901,6 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
goto fail;
}
set_vm_area_page_order(area, page_shift - PAGE_SHIFT);
page_order = vm_area_page_order(area);
/*
* High-order nofail allocations are really expensive and
* potentially dangerous (pre-mature OOM, disruptive reclaim
@ -3958,6 +3955,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
goto fail;
}
set_vm_area_page_order(area, page_order);
return area->addr;
fail: