Commit 4bbb5083 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'bpf-Fix-for-BPF-devmap-percpu-allocation-splat' 



Daniel Borkmann says:

====================
bpf: Fix for BPF devmap percpu allocation splat

The set fixes a splat in devmap percpu allocation when we alloc
the flush bitmap. Patch 1 is a prerequisite for the fix in patch 2,
patch 1 is rather small, so if this could be routed via -net, for
example, with Tejun's Ack that would be good. Patch 3 gets rid of
remaining PCPU_MIN_UNIT_SIZE checks, which are percpu allocator
internals and should not be used.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 3fd3b03b bc6d5031

kernel/bpf/arraymap.c

+1 −1
Original line number Diff line number Diff line
@@ -98,7 +98,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr) 
	array_size += (u64) attr->max_entries * elem_size * num_possible_cpus();



	if (array_size >= U32_MAX - PAGE_SIZE ||

	    elem_size > PCPU_MIN_UNIT_SIZE || bpf_array_alloc_percpu(array)) {

	    bpf_array_alloc_percpu(array)) {

		bpf_map_area_free(array);

		return ERR_PTR(-ENOMEM);

	}

kernel/bpf/devmap.c

+3 −2
Original line number Diff line number Diff line
@@ -111,8 +111,9 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) 
	err = -ENOMEM;



	/* A per cpu bitfield with a bit per possible net device */

	dtab->flush_needed = __alloc_percpu(dev_map_bitmap_size(attr),

					    __alignof__(unsigned long));

	dtab->flush_needed = __alloc_percpu_gfp(dev_map_bitmap_size(attr),

						__alignof__(unsigned long),

						GFP_KERNEL | __GFP_NOWARN);

	if (!dtab->flush_needed)

		goto free_dtab;

kernel/bpf/hashtab.c

+0 −4
Original line number Diff line number Diff line
@@ -317,10 +317,6 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) 
		 */

		goto free_htab;



	if (percpu && round_up(htab->map.value_size, 8) > PCPU_MIN_UNIT_SIZE)

		/* make sure the size for pcpu_alloc() is reasonable */

		goto free_htab;



	htab->elem_size = sizeof(struct htab_elem) +

			  round_up(htab->map.key_size, 8);

	if (percpu)

mm/percpu.c

+10 −5
Original line number Diff line number Diff line
@@ -1329,7 +1329,9 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr) 
 * @gfp: allocation flags

 *

 * Allocate percpu area of @size bytes aligned at @align.  If @gfp doesn't

 * contain %GFP_KERNEL, the allocation is atomic.

 * contain %GFP_KERNEL, the allocation is atomic. If @gfp has __GFP_NOWARN

 * then no warning will be triggered on invalid or failed allocation

 * requests.

 *

 * RETURNS:

 * Percpu pointer to the allocated area on success, NULL on failure.
@@ -1337,10 +1339,11 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr) 
static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,

				 gfp_t gfp)

{

	bool is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL;

	bool do_warn = !(gfp & __GFP_NOWARN);

	static int warn_limit = 10;

	struct pcpu_chunk *chunk;

	const char *err;

	bool is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL;

	int slot, off, cpu, ret;

	unsigned long flags;

	void __percpu *ptr;
@@ -1361,7 +1364,7 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved, 


	if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE ||

		     !is_power_of_2(align))) {

		WARN(true, "illegal size (%zu) or align (%zu) for percpu allocation\n",

		WARN(do_warn, "illegal size (%zu) or align (%zu) for percpu allocation\n",

		     size, align);

		return NULL;

	}
@@ -1482,7 +1485,7 @@ fail_unlock: 
fail:

	trace_percpu_alloc_percpu_fail(reserved, is_atomic, size, align);



	if (!is_atomic && warn_limit) {

	if (!is_atomic && do_warn && warn_limit) {

		pr_warn("allocation failed, size=%zu align=%zu atomic=%d, %s\n",

			size, align, is_atomic, err);

		dump_stack();
@@ -1507,7 +1510,9 @@ fail: 
 *

 * Allocate zero-filled percpu area of @size bytes aligned at @align.  If

 * @gfp doesn't contain %GFP_KERNEL, the allocation doesn't block and can

 * be called from any context but is a lot more likely to fail.

 * be called from any context but is a lot more likely to fail. If @gfp

 * has __GFP_NOWARN then no warning will be triggered on invalid or failed

 * allocation requests.

 *

 * RETURNS:

 * Percpu pointer to the allocated area on success, NULL on failure.

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