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Message-ID: <20240724181916.31776-1-hailong.liu@oppo.com>
Date: Thu, 25 Jul 2024 02:19:12 +0800
From: <hailong.liu@...o.com>
To: Andrew Morton <akpm@...ux-foundation.org>, Uladzislau Rezki
<urezki@...il.com>, Christoph Hellwig <hch@...radead.org>, Lorenzo Stoakes
<lstoakes@...il.com>, Vlastimil Babka <vbabka@...e.cz>, Michal Hocko
<mhocko@...e.com>
CC: Hailong.Liu <hailong.liu@...o.com>, Barry Song <21cnbao@...il.com>,
"Tangquan . Zheng" <zhengtangquan@...o.com>, <linux-mm@...ck.org>,
<linux-kernel@...r.kernel.org>
Subject: [RFC PATCH v1] mm/vmalloc: fix incorrect __vmap_pages_range_noflush() if vm_area_alloc_pages() from high order fallback to order0
From: "Hailong.Liu" <hailong.liu@...o.com>
The scenario where the issue occurs is as follows:
CONFIG: vmap_allow_huge = true && 2M is for PMD_SIZE
kvmalloc(2M)
__vmalloc_node_range(vm_flags=VM_ALLOW_HUGE_VMAP)
vm_area_alloc_pages(order=9) --->allocs order9 failed and fallback to order0
and phys_addr is aligned with PMD_SIZE
vmap_pages_range
vmap_pages_range_noflush
__vmap_pages_range_noflush(page_shift = 21) ----> incorrect vmap *huge* here
Fix it by introducing VM_AREA_ALLOC_PAGES_FALLBACK in page->private if fallback to 0.
Fixes: e9c3cda4d86e ("mm, vmalloc: fix high order __GFP_NOFAIL allocations")
CC: Barry Song <21cnbao@...il.com>
Reported-by: Tangquan.Zheng <zhengtangquan@...o.com>
Signed-off-by: Hailong.Liu <hailong.liu@...o.com>
---
mm/vmalloc.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 03c78fae06f3..b35dfd3eeee3 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -75,6 +75,8 @@ early_param("nohugevmalloc", set_nohugevmalloc);
static const bool vmap_allow_huge = false;
#endif /* CONFIG_HAVE_ARCH_HUGE_VMALLOC */
+#define VM_AREA_ALLOC_PAGES_FALLBACK 0x1
+
bool is_vmalloc_addr(const void *x)
{
unsigned long addr = (unsigned long)kasan_reset_tag(x);
@@ -604,8 +606,13 @@ int __vmap_pages_range_noflush(unsigned long addr, unsigned long end,
WARN_ON(page_shift < PAGE_SHIFT);
if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMALLOC) ||
- page_shift == PAGE_SHIFT)
- return vmap_small_pages_range_noflush(addr, end, prot, pages);
+ page_shift == PAGE_SHIFT ||
+ page_private(pages[0]) == VM_AREA_ALLOC_PAGES_FALLBACK) {
+ int ret = vmap_small_pages_range_noflush(addr, end, prot, pages);
+
+ set_page_private(pages[0], 0);
+ return ret;
+ }
for (i = 0; i < nr; i += 1U << (page_shift - PAGE_SHIFT)) {
int err;
@@ -3583,6 +3590,7 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
/* fall back to the zero order allocations */
alloc_gfp |= __GFP_NOFAIL;
+ fallback = true;
order = 0;
continue;
}
@@ -3608,6 +3616,8 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
cond_resched();
nr_allocated += 1U << order;
}
+ if (nr_allocated && fallback)
+ set_page_private(pages[0], VM_AREA_ALLOC_PAGES_FALLBACK);
return nr_allocated;
}
--
2.34.1
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