From 6304a613a97d6dcd49b93fbad31e9f39d1e138d6 Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Wed, 2 Feb 2022 14:01:58 +0800 Subject: [PATCH] bpf: Use VM_MAP instead of VM_ALLOC for ringbuf commit b293dcc473d22a62dc6d78de2b15e4f49515db56 upstream. After commit 2fd3fb0be1d1 ("kasan, vmalloc: unpoison VM_ALLOC pages after mapping"), non-VM_ALLOC mappings will be marked as accessible in __get_vm_area_node() when KASAN is enabled. But now the flag for ringbuf area is VM_ALLOC, so KASAN will complain out-of-bound access after vmap() returns. Because the ringbuf area is created by mapping allocated pages, so use VM_MAP instead. After the change, info in /proc/vmallocinfo also changes from [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmalloc user to [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmap user Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it") Reported-by: syzbot+5ad567a418794b9b5983@syzkaller.appspotmail.com Signed-off-by: Hou Tao Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220202060158.6260-1-houtao1@huawei.com Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/ringbuf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c index f9913bc65ef8..1e4bf23528a3 100644 --- a/kernel/bpf/ringbuf.c +++ b/kernel/bpf/ringbuf.c @@ -108,7 +108,7 @@ static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node) } rb = vmap(pages, nr_meta_pages + 2 * nr_data_pages, - VM_ALLOC | VM_USERMAP, PAGE_KERNEL); + VM_MAP | VM_USERMAP, PAGE_KERNEL); if (rb) { kmemleak_not_leak(pages); rb->pages = pages;