From 573b3aa6940661dc50c383213d428c27df78be7c Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Mon, 30 Jul 2018 08:49:03 -0700 Subject: [PATCH 1/3] tools/bpftool: fix a percpu_array map dump problem I hit the following problem when I tried to use bpftool to dump a percpu array. $ sudo ./bpftool map show 61: percpu_array name stub flags 0x0 key 4B value 4B max_entries 1 memlock 4096B ... $ sudo ./bpftool map dump id 61 bpftool: malloc.c:2406: sysmalloc: Assertion `(old_top == initial_top (av) && old_size == 0) || \ ((unsigned long) (old_size) >= MINSIZE && \ prev_inuse (old_top) && \ ((unsigned long) old_end & (pagesize - 1)) == 0)' failed. Aborted Further debugging revealed that this is due to miscommunication between bpftool and kernel. For example, for the above percpu_array with value size of 4B. The map info returned to user space has value size of 4B. In bpftool, the values array for lookup is allocated like: info->value_size * get_possible_cpus() = 4 * get_possible_cpus() In kernel (kernel/bpf/syscall.c), the values array size is rounded up to multiple of 8. round_up(map->value_size, 8) * num_possible_cpus() = 8 * num_possible_cpus() So when kernel copies the values to user buffer, the kernel will overwrite beyond user buffer boundary. This patch fixed the issue by allocating and stepping through percpu map value array properly in bpftool. Fixes: 71bb428fe2c19 ("tools: bpf: add bpftool") Signed-off-by: Yonghong Song Signed-off-by: Daniel Borkmann --- tools/bpf/bpftool/map.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index 097b1a5e046b..f74a8bcbda87 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include #include @@ -90,7 +91,8 @@ static bool map_is_map_of_progs(__u32 type) static void *alloc_value(struct bpf_map_info *info) { if (map_is_per_cpu(info->type)) - return malloc(info->value_size * get_possible_cpus()); + return malloc(round_up(info->value_size, 8) * + get_possible_cpus()); else return malloc(info->value_size); } @@ -161,9 +163,10 @@ static void print_entry_json(struct bpf_map_info *info, unsigned char *key, jsonw_name(json_wtr, "value"); print_hex_data_json(value, info->value_size); } else { - unsigned int i, n; + unsigned int i, n, step; n = get_possible_cpus(); + step = round_up(info->value_size, 8); jsonw_name(json_wtr, "key"); print_hex_data_json(key, info->key_size); @@ -176,7 +179,7 @@ static void print_entry_json(struct bpf_map_info *info, unsigned char *key, jsonw_int_field(json_wtr, "cpu", i); jsonw_name(json_wtr, "value"); - print_hex_data_json(value + i * info->value_size, + print_hex_data_json(value + i * step, info->value_size); jsonw_end_object(json_wtr); @@ -207,9 +210,10 @@ static void print_entry_plain(struct bpf_map_info *info, unsigned char *key, printf("\n"); } else { - unsigned int i, n; + unsigned int i, n, step; n = get_possible_cpus(); + step = round_up(info->value_size, 8); printf("key:\n"); fprint_hex(stdout, key, info->key_size, " "); @@ -217,7 +221,7 @@ static void print_entry_plain(struct bpf_map_info *info, unsigned char *key, for (i = 0; i < n; i++) { printf("value (CPU %02d):%c", i, info->value_size > 16 ? '\n' : ' '); - fprint_hex(stdout, value + i * info->value_size, + fprint_hex(stdout, value + i * step, info->value_size, " "); printf("\n"); } From 2d55d614fcf58187e2937dba11643b9471cd64d7 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Fri, 27 Jul 2018 20:20:08 -0700 Subject: [PATCH 2/3] net: xsk: don't return frames via the allocator on error MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit xdp_return_buff() is used when frame has been successfully handled (transmitted) or if an error occurred during delayed processing and there is no way to report it back to xdp_do_redirect(). In case of __xsk_rcv_zc() error is propagated all the way back to the driver, so there is no need to call xdp_return_buff(). Driver will recycle the frame anyway after seeing that error happened. Fixes: 173d3adb6f43 ("xsk: add zero-copy support for Rx") Signed-off-by: Jakub Kicinski Acked-by: Björn Töpel Signed-off-by: Daniel Borkmann --- net/xdp/xsk.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 72335c2e8108..4e937cd7c17d 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -84,10 +84,8 @@ static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len) { int err = xskq_produce_batch_desc(xs->rx, (u64)xdp->handle, len); - if (err) { - xdp_return_buff(xdp); + if (err) xs->rx_dropped++; - } return err; } From 8c85cbdf371f9ddf256ecc5d9548b26ee8fcfe2f Mon Sep 17 00:00:00 2001 From: Mathieu Xhonneux Date: Wed, 1 Aug 2018 15:34:54 +0000 Subject: [PATCH 3/3] selftests/bpf: update test_lwt_seg6local.sh according to iproute2 The shell file for test_lwt_seg6local contains an early iproute2 syntax for installing a seg6local End.BPF route. iproute2 support for this feature has recently been upstreamed, but with an additional keyword required. This patch updates test_lwt_seg6local.sh to the definitive iproute2 syntax Signed-off-by: Mathieu Xhonneux Acked-by: Yonghong Song Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/test_lwt_seg6local.sh | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/bpf/test_lwt_seg6local.sh b/tools/testing/selftests/bpf/test_lwt_seg6local.sh index 270fa8f49573..785eabf2a593 100755 --- a/tools/testing/selftests/bpf/test_lwt_seg6local.sh +++ b/tools/testing/selftests/bpf/test_lwt_seg6local.sh @@ -115,14 +115,14 @@ ip netns exec ns2 ip -6 route add fb00::6 encap bpf in obj test_lwt_seg6local.o ip netns exec ns2 ip -6 route add fd00::1 dev veth3 via fb00::43 scope link ip netns exec ns3 ip -6 route add fc42::1 dev veth5 via fb00::65 -ip netns exec ns3 ip -6 route add fd00::1 encap seg6local action End.BPF obj test_lwt_seg6local.o sec add_egr_x dev veth4 +ip netns exec ns3 ip -6 route add fd00::1 encap seg6local action End.BPF endpoint obj test_lwt_seg6local.o sec add_egr_x dev veth4 -ip netns exec ns4 ip -6 route add fd00::2 encap seg6local action End.BPF obj test_lwt_seg6local.o sec pop_egr dev veth6 +ip netns exec ns4 ip -6 route add fd00::2 encap seg6local action End.BPF endpoint obj test_lwt_seg6local.o sec pop_egr dev veth6 ip netns exec ns4 ip -6 addr add fc42::1 dev lo ip netns exec ns4 ip -6 route add fd00::3 dev veth7 via fb00::87 ip netns exec ns5 ip -6 route add fd00::4 table 117 dev veth9 via fb00::109 -ip netns exec ns5 ip -6 route add fd00::3 encap seg6local action End.BPF obj test_lwt_seg6local.o sec inspect_t dev veth8 +ip netns exec ns5 ip -6 route add fd00::3 encap seg6local action End.BPF endpoint obj test_lwt_seg6local.o sec inspect_t dev veth8 ip netns exec ns6 ip -6 addr add fb00::6/16 dev lo ip netns exec ns6 ip -6 addr add fd00::4/16 dev lo