This is a note to let you know that I've just added the patch titled
bpf: fix mlock precharge on arraymaps
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: bpf-fix-mlock-precharge-on-arraymaps.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Fri Mar 9 14:20:51 PST 2018
From: Daniel Borkmann daniel@iogearbox.net Date: Thu, 8 Mar 2018 16:17:33 +0100 Subject: bpf: fix mlock precharge on arraymaps To: gregkh@linuxfoundation.org Cc: ast@kernel.org, daniel@iogearbox.net, stable@vger.kernel.org, Dennis Zhou dennisszhou@gmail.com Message-ID: 56632230ccbd31f06f33af4c6ac9fcbc88506825.1520521792.git.daniel@iogearbox.net
From: Daniel Borkmann daniel@iogearbox.net
[ upstream commit 9c2d63b843a5c8a8d0559cc067b5398aa5ec3ffc ]
syzkaller recently triggered OOM during percpu map allocation; while there is work in progress by Dennis Zhou to add __GFP_NORETRY semantics for percpu allocator under pressure, there seems also a missing bpf_map_precharge_memlock() check in array map allocation.
Given today the actual bpf_map_charge_memlock() happens after the find_and_alloc_map() in syscall path, the bpf_map_precharge_memlock() is there to bail out early before we go and do the map setup work when we find that we hit the limits anyway. Therefore add this for array map as well.
Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements") Fixes: a10423b87a7e ("bpf: introduce BPF_MAP_TYPE_PERCPU_ARRAY map") Reported-by: syzbot+adb03f3f0bb57ce3acda@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Cc: Dennis Zhou dennisszhou@gmail.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/bpf/arraymap.c | 29 ++++++++++++++++++----------- 1 file changed, 18 insertions(+), 11 deletions(-)
--- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -48,8 +48,9 @@ static struct bpf_map *array_map_alloc(u bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY; u32 elem_size, index_mask, max_entries; bool unpriv = !capable(CAP_SYS_ADMIN); + u64 cost, array_size, mask64; struct bpf_array *array; - u64 array_size, mask64; + int ret;
/* check sanity of attributes */ if (attr->max_entries == 0 || attr->key_size != 4 || @@ -92,8 +93,19 @@ static struct bpf_map *array_map_alloc(u array_size += (u64) max_entries * elem_size;
/* make sure there is no u32 overflow later in round_up() */ - if (array_size >= U32_MAX - PAGE_SIZE) + cost = array_size; + if (cost >= U32_MAX - PAGE_SIZE) return ERR_PTR(-ENOMEM); + if (percpu) { + cost += (u64)attr->max_entries * elem_size * num_possible_cpus(); + if (cost >= U32_MAX - PAGE_SIZE) + return ERR_PTR(-ENOMEM); + } + cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; + + ret = bpf_map_precharge_memlock(cost); + if (ret < 0) + return ERR_PTR(ret);
/* allocate all map elements and zero-initialize them */ array = bpf_map_area_alloc(array_size); @@ -108,20 +120,15 @@ static struct bpf_map *array_map_alloc(u array->map.value_size = attr->value_size; array->map.max_entries = attr->max_entries; array->map.map_flags = attr->map_flags; + array->map.pages = cost; array->elem_size = elem_size;
- if (!percpu) - goto out; - - 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)) { + if (percpu && + (elem_size > PCPU_MIN_UNIT_SIZE || + bpf_array_alloc_percpu(array))) { bpf_map_area_free(array); return ERR_PTR(-ENOMEM); } -out: - array->map.pages = round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT;
return &array->map; }
Patches currently in stable-queue which might be from daniel@iogearbox.net are
queue-4.9/bpf-fix-mlock-precharge-on-arraymaps.patch queue-4.9/bpf-x64-implement-retpoline-for-tail-call.patch queue-4.9/bpf-arm64-fix-out-of-bounds-access-in-tail-call.patch queue-4.9/bpf-fix-wrong-exposure-of-map_flags-into-fdinfo-for-lpm.patch queue-4.9/bpf-ppc64-fix-out-of-bounds-access-in-tail-call.patch queue-4.9/bpf-add-schedule-points-in-percpu-arrays-management.patch