From 7984c27c2c5cd3298de8afdba3e1bd46f884e934 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Tue, 10 Jan 2017 16:57:30 -0800 Subject: [PATCH] bpf: do not use KMALLOC_SHIFT_MAX Commit 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@kernel.org Signed-off-by: Michal Hocko Acked-by: Christoph Lameter Cc: Alexei Starovoitov Cc: Andrey Konovalov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/bpf/arraymap.c | 2 +- kernel/bpf/hashtab.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index a2ac051c342f..229a5d5df977 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -56,7 +56,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr) 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 --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 34debc1a9641..3f2bb58952d8 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -274,7 +274,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) */ 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 -- 2.39.5