From: Michal Hocko <mhocko@xxxxxxxx>
Subject: bpf: do not use KMALLOC_SHIFT_MAX
01b3f52157ff ("bpf: fix allocation warnings in bpf maps and integer
overflow") has added checks for the maximum allocateable size. It
(ab)used KMALLOC_SHIFT_MAX for that purpose. While this is not incorrect
it is not very clean because we already have KMALLOC_MAX_SIZE for this
very reason so let's change both checks to use KMALLOC_MAX_SIZE instead.
The original motivation for using KMALLOC_SHIFT_MAX was to work around an
incorrect KMALLOC_MAX_SIZE which could lead to allocation warnings but it
is no longer needed since "slab: make sure that KMALLOC_MAX_SIZE will fit
into MAX_ORDER".
Link: http://lkml.kernel.org/r/20161220130659.16461-3-mhocko@xxxxxxxxxx
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Christoph Lameter <cl@xxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/bpf/arraymap.c | 2 +-
kernel/bpf/hashtab.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff -puN kernel/bpf/arraymap.c~bpf-do-not-use-kmalloc_shift_max kernel/bpf/arraymap.c
--- a/kernel/bpf/arraymap.c~bpf-do-not-use-kmalloc_shift_max
+++ a/kernel/bpf/arraymap.c
@@ -56,7 +56,7 @@ static struct bpf_map *array_map_alloc(u
attr->value_size == 0 || attr->map_flags)
return ERR_PTR(-EINVAL);
- if (attr->value_size >= 1 << (KMALLOC_SHIFT_MAX - 1))
+ if (attr->value_size > KMALLOC_MAX_SIZE)
/* if value_size is bigger, the user space won't be able to
* access the elements.
*/
diff -puN kernel/bpf/hashtab.c~bpf-do-not-use-kmalloc_shift_max kernel/bpf/hashtab.c
--- a/kernel/bpf/hashtab.c~bpf-do-not-use-kmalloc_shift_max
+++ a/kernel/bpf/hashtab.c
@@ -274,7 +274,7 @@ static struct bpf_map *htab_map_alloc(un
*/
goto free_htab;
- if (htab->map.value_size >= (1 << (KMALLOC_SHIFT_MAX - 1)) -
+ if (htab->map.value_size >= KMALLOC_MAX_SIZE -
MAX_BPF_STACK - sizeof(struct htab_elem))
/* if value_size is bigger, the user space won't be able to
* access the elements via bpf syscall. This check also makes
_
--
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