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Subject[PATCH] mm/vmalloc: Add check for KMEM_CACHE
Date
As KMEM_CACHE may return NULL pointer, it should
be better to check the return value in order to
avoid NULL pointer dereference in kmem_cache_zalloc.

Fixes: 68ad4a330433 ("mm/vmalloc.c: keep track of free blocks for vmap allocation")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
---
mm/vmalloc.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index ccaa461998f3..df3e59f614cc 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2426,15 +2426,17 @@ void __init vmalloc_init(void)
}

/* Import existing vmlist entries. */
- for (tmp = vmlist; tmp; tmp = tmp->next) {
- va = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
- if (WARN_ON_ONCE(!va))
- continue;
+ if (!WARN_ON_ONCE(!vmap_area_cachep)) {
+ for (tmp = vmlist; tmp; tmp = tmp->next) {
+ va = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
+ if (WARN_ON_ONCE(!va))
+ continue;

- va->va_start = (unsigned long)tmp->addr;
- va->va_end = va->va_start + tmp->size;
- va->vm = tmp;
- insert_vmap_area(va, &vmap_area_root, &vmap_area_list);
+ va->va_start = (unsigned long)tmp->addr;
+ va->va_end = va->va_start + tmp->size;
+ va->vm = tmp;
+ insert_vmap_area(va, &vmap_area_root, &vmap_area_list);
+ }
}

/*
--
2.25.1
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