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kmsan: remove hard-coded GFP_KERNEL flags 

kmsan_vmap_pages_range_noflush() allocates its temp s_pages/o_pages arrays
with GFP_KERNEL, which may sleep.  This is inconsistent with vmalloc() as
it will support non-blocking requests later.

Plumb gfp_mask through the kmsan_vmap_pages_range_noflush(), so it can use
it internally for its demand.

Please note, the subsequent __vmap_pages_range_noflush() still uses
GFP_KERNEL and can sleep.  If a caller runs under reclaim constraints,
sleeping is forbidden, it must establish the appropriate memalloc scope
API.

Link: https://lkml.kernel.org/r/20251007122035.56347-8-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Uladzislau Rezki (Sony) 2025-10-07 14:20:32 +02:00 committed by Andrew Morton
parent ad435e79f8
commit b186a94227
5 changed files with 27 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/linux/kmsan.h
View File

@ -133,6 +133,7 @@ void kmsan_kfree_large(const void *ptr);
* @prot: page protection flags used for vmap.
* @pages: array of pages.
* @page_shift: page_shift passed to vmap_range_noflush().
* @gfp_mask: gfp_mask to use internally.
*
* KMSAN maps shadow and origin pages of @pages into contiguous ranges in
* vmalloc metadata address range. Returns 0 on success, callers must check
@ -142,7 +143,8 @@ int __must_check kmsan_vmap_pages_range_noflush(unsigned long start,
unsigned long end,
pgprot_t prot,
struct page **pages,
unsigned int page_shift);
unsigned int page_shift,
gfp_t gfp_mask);
/**
* kmsan_vunmap_kernel_range_noflush() - Notify KMSAN about a vunmap.
@ -347,7 +349,7 @@ static inline void kmsan_kfree_large(const void *ptr)
static inline int __must_check kmsan_vmap_pages_range_noflush(
unsigned long start, unsigned long end, pgprot_t prot,
struct page **pages, unsigned int page_shift)
struct page **pages, unsigned int page_shift, gfp_t gfp_mask)
{
return 0;
}

4
mm/internal.h
View File

@ -1355,7 +1355,7 @@ size_t splice_folio_into_pipe(struct pipe_inode_info *pipe,
#ifdef CONFIG_MMU
void __init vmalloc_init(void);
int __must_check vmap_pages_range_noflush(unsigned long addr, unsigned long end,
pgprot_t prot, struct page **pages, unsigned int page_shift);
pgprot_t prot, struct page **pages, unsigned int page_shift, gfp_t gfp_mask);
unsigned int get_vm_area_page_order(struct vm_struct *vm);
#else
static inline void vmalloc_init(void)
@ -1364,7 +1364,7 @@ static inline void vmalloc_init(void)
static inline
int __must_check vmap_pages_range_noflush(unsigned long addr, unsigned long end,
pgprot_t prot, struct page **pages, unsigned int page_shift)
pgprot_t prot, struct page **pages, unsigned int page_shift, gfp_t gfp_mask)
{
return -EINVAL;
}

6
mm/kmsan/shadow.c
View File

@ -215,7 +215,7 @@ void kmsan_free_page(struct page *page, unsigned int order)
int kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end,
pgprot_t prot, struct page **pages,
unsigned int page_shift)
unsigned int page_shift, gfp_t gfp_mask)
{
unsigned long shadow_start, origin_start, shadow_end, origin_end;
struct page **s_pages, **o_pages;
@ -230,8 +230,8 @@ int kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end,
return 0;
nr = (end - start) / PAGE_SIZE;
s_pages = kcalloc(nr, sizeof(*s_pages), GFP_KERNEL);
o_pages = kcalloc(nr, sizeof(*o_pages), GFP_KERNEL);
s_pages = kcalloc(nr, sizeof(*s_pages), gfp_mask);
o_pages = kcalloc(nr, sizeof(*o_pages), gfp_mask);
if (!s_pages || !o_pages) {
err = -ENOMEM;
goto ret;

2
mm/percpu-vm.c
View File

@ -194,7 +194,7 @@ static int __pcpu_map_pages(unsigned long addr, struct page **pages,
int nr_pages)
{
return vmap_pages_range_noflush(addr, addr + (nr_pages << PAGE_SHIFT),
PAGE_KERNEL, pages, PAGE_SHIFT);
PAGE_KERNEL, pages, PAGE_SHIFT, GFP_KERNEL);
}
/**

26
mm/vmalloc.c
View File

@ -671,16 +671,28 @@ int __vmap_pages_range_noflush(unsigned long addr, unsigned long end,
}
int vmap_pages_range_noflush(unsigned long addr, unsigned long end,
pgprot_t prot, struct page **pages, unsigned int page_shift)
pgprot_t prot, struct page **pages, unsigned int page_shift,
gfp_t gfp_mask)
{
int ret = kmsan_vmap_pages_range_noflush(addr, end, prot, pages,
page_shift);
page_shift, gfp_mask);
if (ret)
return ret;
return __vmap_pages_range_noflush(addr, end, prot, pages, page_shift);
}
static int __vmap_pages_range(unsigned long addr, unsigned long end,
pgprot_t prot, struct page **pages, unsigned int page_shift,
gfp_t gfp_mask)
{
int err;
err = vmap_pages_range_noflush(addr, end, prot, pages, page_shift, gfp_mask);
flush_cache_vmap(addr, end);
return err;
}
/**
* vmap_pages_range - map pages to a kernel virtual address
* @addr: start of the VM area to map
@ -696,11 +708,7 @@ int vmap_pages_range_noflush(unsigned long addr, unsigned long end,
int vmap_pages_range(unsigned long addr, unsigned long end,
pgprot_t prot, struct page **pages, unsigned int page_shift)
{
int err;
err = vmap_pages_range_noflush(addr, end, prot, pages, page_shift);
flush_cache_vmap(addr, end);
return err;
return __vmap_pages_range(addr, end, prot, pages, page_shift, GFP_KERNEL);
}
static int check_sparse_vm_area(struct vm_struct *area, unsigned long start,
@ -3839,8 +3847,8 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
*/
flags = memalloc_apply_gfp_scope(gfp_mask);
do {
ret = vmap_pages_range(addr, addr + size, prot, area->pages,
page_shift);
ret = __vmap_pages_range(addr, addr + size, prot, area->pages,
page_shift, nested_gfp);
if (nofail && (ret < 0))
schedule_timeout_uninterruptible(1);
} while (nofail && (ret < 0));