Commit 7984c27c authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds

bpf: do not use KMALLOC_SHIFT_MAX

Commit 01b3f521 ("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@kernel.orgSigned-off-by: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarChristoph Lameter <cl@linux.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bb1107f7
...@@ -56,7 +56,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr) ...@@ -56,7 +56,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr)
attr->value_size == 0 || attr->map_flags) attr->value_size == 0 || attr->map_flags)
return ERR_PTR(-EINVAL); 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 /* if value_size is bigger, the user space won't be able to
* access the elements. * access the elements.
*/ */
......
...@@ -274,7 +274,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) ...@@ -274,7 +274,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
*/ */
goto free_htab; 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)) MAX_BPF_STACK - sizeof(struct htab_elem))
/* if value_size is bigger, the user space won't be able to /* if value_size is bigger, the user space won't be able to
* access the elements via bpf syscall. This check also makes * access the elements via bpf syscall. This check also makes
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment