June 2025 - Linux-kselftest-mirror

[PATCH net v2] net: clear the dst when changing skb protocol

by Jakub Kicinski

A not-so-careful NAT46 BPF program can crash the kernel if it indiscriminately flips ingress packets from v4 to v6: BUG: kernel NULL pointer dereference, address: 0000000000000000 ip6_rcv_core (net/ipv6/ip6_input.c:190:20) ipv6_rcv (net/ipv6/ip6_input.c:306:8) process_backlog (net/core/dev.c:6186:4) napi_poll (net/core/dev.c:6906:9) net_rx_action (net/core/dev.c:7028:13) do_softirq (kernel/softirq.c:462:3) netif_rx (net/core/dev.c:5326:3) dev_loopback_xmit (net/core/dev.c:4015:2) ip_mc_finish_output (net/ipv4/ip_output.c:363:8) NF_HOOK (./include/linux/netfilter.h:314:9) ip_mc_output (net/ipv4/ip_output.c:400:5) dst_output (./include/net/dst.h:459:9) ip_local_out (net/ipv4/ip_output.c:130:9) ip_send_skb (net/ipv4/ip_output.c:1496:8) udp_send_skb (net/ipv4/udp.c:1040:8) udp_sendmsg (net/ipv4/udp.c:1328:10) The output interface has a 4->6 program attached at ingress. We try to loop the multicast skb back to the sending socket. Ingress BPF runs as part of netif_rx(), pushes a valid v6 hdr and changes skb->protocol to v6. We enter ip6_rcv_core which tries to use skb_dst(). But the dst is still an IPv4 one left after IPv4 mcast output. Clear the dst in all BPF helpers which change the protocol. Also clear the dst if we did an encap or decap as those will most likely make the dst stale. Try to preserve metadata dsts, those may carry non-routing metadata. Reviewed-by: Maciej Żenczykowski <maze(a)google.com> Acked-by: Daniel Borkmann <daniel(a)iogearbox.net> Fixes: d219df60a70e ("bpf: Add ipip6 and ip6ip decap support for bpf_skb_adjust_room()") Fixes: 1b00e0dfe7d0 ("bpf: update skb->protocol in bpf_skb_net_grow") Fixes: 6578171a7ff0 ("bpf: add bpf_skb_change_proto helper") Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> --- v2: - drop on encap/decap - fix typo (protcol) - add the test to the Makefile v1: https://lore.kernel.org/20250604210604.257036-1-kuba@kernel.org I wonder if we should not skip ingress (tc_skip_classify?) for looped back packets in the first place. But that doesn't seem robust enough vs multiple redirections to solve the crash. Ignoring LOOPBACK packets (like the NAT46 prog should) doesn't work either, since BPF can change pkt_type arbitrarily. CC: martin.lau(a)linux.dev CC: daniel(a)iogearbox.net CC: john.fastabend(a)gmail.com CC: eddyz87(a)gmail.com CC: sdf(a)fomichev.me CC: haoluo(a)google.com CC: willemb(a)google.com CC: william.xuanziyang(a)huawei.com CC: alan.maguire(a)oracle.com CC: bpf(a)vger.kernel.org CC: edumazet(a)google.com CC: maze(a)google.com CC: shuah(a)kernel.org CC: linux-kselftest(a)vger.kernel.org CC: yonghong.song(a)linux.dev --- tools/testing/selftests/net/Makefile | 1 + net/core/filter.c | 31 +++++++++++++++++++------- tools/testing/selftests/net/nat6to4.sh | 15 +++++++++++++ 3 files changed, 39 insertions(+), 8 deletions(-) create mode 100755 tools/testing/selftests/net/nat6to4.sh diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index ea84b88bcb30..ab996bd22a5f 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -27,6 +27,7 @@ TEST_PROGS += amt.sh TEST_PROGS += unicast_extensions.sh TEST_PROGS += udpgro_fwd.sh TEST_PROGS += udpgro_frglist.sh +TEST_PROGS += nat6to4.sh TEST_PROGS += veth.sh TEST_PROGS += ioam6.sh TEST_PROGS += gro.sh diff --git a/net/core/filter.c b/net/core/filter.c index 327ca73f9cd7..d5917d6446f2 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3406,8 +3406,14 @@ BPF_CALL_3(bpf_skb_change_proto, struct sk_buff *, skb, __be16, proto, * need to be verified first. */ ret = bpf_skb_proto_xlat(skb, proto); + if (ret) + return ret; + bpf_compute_data_pointers(skb); - return ret; + if (skb_valid_dst(skb)) + skb_dst_drop(skb); + + return 0; } static const struct bpf_func_proto bpf_skb_change_proto_proto = { @@ -3554,6 +3560,9 @@ static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff, else if (skb->protocol == htons(ETH_P_IPV6) && flags & BPF_F_ADJ_ROOM_ENCAP_L3_IPV4) skb->protocol = htons(ETH_P_IP); + + if (skb_valid_dst(skb)) + skb_dst_drop(skb); } if (skb_is_gso(skb)) { @@ -3581,6 +3590,7 @@ static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff, static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff, u64 flags) { + bool decap = flags & BPF_F_ADJ_ROOM_DECAP_L3_MASK; int ret; if (unlikely(flags & ~(BPF_F_ADJ_ROOM_FIXED_GSO | @@ -3603,13 +3613,18 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff, if (unlikely(ret < 0)) return ret; - /* Match skb->protocol to new outer l3 protocol */ - if (skb->protocol == htons(ETH_P_IP) && - flags & BPF_F_ADJ_ROOM_DECAP_L3_IPV6) - skb->protocol = htons(ETH_P_IPV6); - else if (skb->protocol == htons(ETH_P_IPV6) && - flags & BPF_F_ADJ_ROOM_DECAP_L3_IPV4) - skb->protocol = htons(ETH_P_IP); + if (decap) { + /* Match skb->protocol to new outer l3 protocol */ + if (skb->protocol == htons(ETH_P_IP) && + flags & BPF_F_ADJ_ROOM_DECAP_L3_IPV6) + skb->protocol = htons(ETH_P_IPV6); + else if (skb->protocol == htons(ETH_P_IPV6) && + flags & BPF_F_ADJ_ROOM_DECAP_L3_IPV4) + skb->protocol = htons(ETH_P_IP); + + if (skb_valid_dst(skb)) + skb_dst_drop(skb); + } if (skb_is_gso(skb)) { struct skb_shared_info *shinfo = skb_shinfo(skb); diff --git a/tools/testing/selftests/net/nat6to4.sh b/tools/testing/selftests/net/nat6to4.sh new file mode 100755 index 000000000000..0ee859b622a4 --- /dev/null +++ b/tools/testing/selftests/net/nat6to4.sh @@ -0,0 +1,15 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +NS="ns-peer-$(mktemp -u XXXXXX)" + +ip netns add "${NS}" +ip -netns "${NS}" link set lo up +ip -netns "${NS}" route add default via 127.0.0.2 dev lo + +tc -n "${NS}" qdisc add dev lo ingress +tc -n "${NS}" filter add dev lo ingress prio 4 protocol ip \ + bpf object-file nat6to4.bpf.o section schedcls/egress4/snat4 direct-action + +ip netns exec "${NS}" \ + bash -c 'echo 012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789abc | socat - UDP4-DATAGRAM:224.1.0.1:6666,ip-multicast-loop=1' -- 2.49.0

6 months

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ATS 2025 Schedule Now Live – Register Today!

by Gustavo Padovan

Hello everyone, The schedule for the Automated Testing Summit (ATS) 2025 is now live! You can now explore the full program and speaker list at: 🔗 https://ats25.sched.com/ This year’s ATS will be packed with talks and discussions focused on scaling test infrastructure, improving collaboration across projects, and pushing the boundaries of automation in the Linux ecosystem. 📍 ATS 2025 will take place as a co-located event at the Open Source Summit North America, on June 26th in Denver, CO. If you haven’t yet registered, you can do so here: 🔗 https://events.linuxfoundation.org/open-source-summit-north-america/feature… You can attend in person or virtually. We look forward to seeing you there! Best regards, The KernelCI Team -- Gustavo Padovan Collabora Ltd.

6 months

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[RFC net-next 6/6] selftests: drv-net: add test for RSS on flow label

by Jakub Kicinski

Add a simple test for checking that RSS on flow label works, and that its rejected for IPv4 flows. # ./tools/testing/selftests/drivers/net/hw/rss_flow_label.py TAP version 13 1..2 ok 1 rss_flow_label.test_rss_flow_label ok 2 rss_flow_label.test_rss_flow_label_6only # Totals: pass:2 fail:0 xfail:0 xpass:0 skip:0 error:0 Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> --- CC: shuah(a)kernel.org CC: sdf(a)fomichev.me CC: linux-kselftest(a)vger.kernel.org --- .../testing/selftests/drivers/net/hw/Makefile | 1 + .../drivers/net/hw/rss_flow_label.py | 151 ++++++++++++++++++ 2 files changed, 152 insertions(+) create mode 100755 tools/testing/selftests/drivers/net/hw/rss_flow_label.py diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile index df2c047ffa90..56bf1f1b8377 100644 --- a/tools/testing/selftests/drivers/net/hw/Makefile +++ b/tools/testing/selftests/drivers/net/hw/Makefile @@ -17,6 +17,7 @@ TEST_PROGS = \ loopback.sh \ pp_alloc_fail.py \ rss_ctx.py \ + rss_flow_label.py \ rss_input_xfrm.py \ tso.py \ xsk_reconfig.py \ diff --git a/tools/testing/selftests/drivers/net/hw/rss_flow_label.py b/tools/testing/selftests/drivers/net/hw/rss_flow_label.py new file mode 100755 index 000000000000..e471e13160ae --- /dev/null +++ b/tools/testing/selftests/drivers/net/hw/rss_flow_label.py @@ -0,0 +1,151 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0 + +""" +Tests for RSS hashing on IPv6 Flow Label. +""" + +import glob +import socket +from lib.py import CmdExitFailure +from lib.py import ksft_run, ksft_exit, ksft_eq, ksft_ge, ksft_in, \ + ksft_not_in, ksft_raises, KsftSkipEx +from lib.py import bkg, cmd, defer, fd_read_timeout, rand_port +from lib.py import NetDrvEpEnv + + +def _ethtool_get_cfg(cfg, fl_type): + descr = cmd(f"ethtool -n {cfg.ifname} rx-flow-hash {fl_type}").stdout + + converter = { + "IP SA": "s", + "IP DA": "d", + "L3 proto": "t", + "L4 bytes 0 & 1 [TCP/UDP src port]": "f", + "L4 bytes 2 & 3 [TCP/UDP dst port]": "n", + "IPv6 Flow Label": "l", + } + + ret = "" + for line in descr.split("\n")[1:-2]: + # if this raises we probably need to add more keys to converter above + ret += converter[line] + return ret + + +def _traffic(cfg, one_sock, one_cpu): + local_port = rand_port(socket.SOCK_DGRAM) + remote_port = rand_port(socket.SOCK_DGRAM) + + sock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM) + sock.bind(("", local_port)) + sock.connect((cfg.remote_addr_v["6"], 0)) + if one_sock: + send = f"exec 5<>/dev/udp/{cfg.addr_v['6']}/{local_port}; " \ + "for i in `seq 20`; do echo a >&5; sleep 0.02; done; exec 5>&-" + else: + send = "for i in `seq 20`; do echo a | socat -t0.02 - UDP6:" \ + f"[{cfg.addr_v['6']}]:{local_port},sourceport={remote_port}; done" + + cpus = set() + with bkg(send, shell=True, host=cfg.remote, exit_wait=True): + for _ in range(20): + fd_read_timeout(sock.fileno(), 1) + cpu = sock.getsockopt(socket.SOL_SOCKET, socket.SO_INCOMING_CPU) + cpus.add(cpu) + + if one_cpu: + ksft_eq(len(cpus), 1, + f"{one_sock=} - expected one CPU, got traffic on: {cpus=}") + else: + ksft_ge(len(cpus), 2, + f"{one_sock=} - expected many CPUs, got traffic on: {cpus=}") + + +def test_rss_flow_label(cfg): + """ + Test hashing on IPv6 flow label. Send traffic over a single socket + and over multiple sockets. Depend on the remote having auto-label + enabled so that it randomizes the label per socket. + """ + + cfg.require_ipver("6") + cfg.require_cmd("socat", remote=True) + if not hasattr(socket, "SO_INCOMING_CPU"): + raise KsftSkipEx("socket.SO_INCOMING_CPU was added in Python 3.11") + + # 1 is the default, if someone changed it we probably shouldn"t mess with it + af = cmd("cat /proc/sys/net/ipv6/auto_flowlabels", host=cfg.remote).stdout + if af.strip() != "1": + raise KsftSkipEx("Remote does not have auto_flowlabels enabled") + + qcnt = len(glob.glob(f"/sys/class/net/{cfg.ifname}/queues/rx-*")) + if qcnt < 2: + raise KsftSkipEx(f"Local has only {qcnt} queues") + + # Enable flow label hashing for UDP6 + initial = _ethtool_get_cfg(cfg, "udp6") + no_lbl = initial.replace("l", "") + if "l" not in initial: + try: + cmd(f"ethtool -N {cfg.ifname} rx-flow-hash udp6 l{no_lbl}") + except CmdExitFailure as exc: + raise KsftSkipEx("Device doesn't support Flow Label for UDP6") from exc + + defer(cmd, f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {initial}") + + _traffic(cfg, one_sock=True, one_cpu=True) + _traffic(cfg, one_sock=False, one_cpu=False) + + # Disable it, we should see no hashing (reset was already defer()ed) + cmd(f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {no_lbl}") + + _traffic(cfg, one_sock=False, one_cpu=True) + + +def _check_v4_flow_types(cfg): + for fl_type in ["tcp4", "udp4", "ah4", "esp4", "sctp4"]: + try: + cur = cmd(f"ethtool -n {cfg.ifname} rx-flow-hash {fl_type}").stdout + ksft_not_in("Flow Label", cur, + comment=f"{fl_type=} has Flow Label:" + cur) + except CmdExitFailure: + # Probably does not support this flow type + pass + + +def test_rss_flow_label_6only(cfg): + """ + Test interactions with IPv4 flow types. It should not be possible to set + IPv6 Flow Label hashing for an IPv4 flow type. The Flow Label should also + not appear in the IPv4 "current config". + """ + + with ksft_raises(CmdExitFailure) as cm: + cmd(f"ethtool -N {cfg.ifname} rx-flow-hash tcp4 sdfnl") + ksft_in("Invalid argument", cm.exception.cmd.stderr) + + _check_v4_flow_types(cfg) + + # Try to enable Flow Labels and check again, in case it leaks thru + initial = _ethtool_get_cfg(cfg, "udp6") + changed = initial.replace("l", "") if "l" in initial else initial + "l" + + cmd(f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {changed}") + restore = defer(cmd, f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {initial}") + + _check_v4_flow_types(cfg) + restore.exec() + _check_v4_flow_types(cfg) + + +def main() -> None: + with NetDrvEpEnv(__file__, nsim_test=False) as cfg: + ksft_run([test_rss_flow_label, + test_rss_flow_label_6only], + args=(cfg, )) + ksft_exit() + + +if __name__ == "__main__": + main() -- 2.49.0

6 months

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[RFC net-next 5/6] selftests: drv-net: import things in lib one by one

by Jakub Kicinski

pylint doesn't understand our path hacks, and it generates a lot of warnings for driver tests. Import what we use one by one, this is hopefully not too tedious and it makes pylint happy. Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> --- CC: shuah(a)kernel.org CC: mohan.prasad(a)microchip.com CC: sdf(a)fomichev.me CC: dw(a)davidwei.uk CC: linux-kselftest(a)vger.kernel.org --- .../selftests/drivers/net/hw/lib/py/__init__.py | 17 +++++++++++++++++ .../selftests/drivers/net/lib/py/__init__.py | 14 ++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py b/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py index b582885786f5..56ff11074b55 100644 --- a/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py +++ b/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py @@ -7,8 +7,25 @@ KSFT_DIR = (Path(__file__).parent / "../../../../..").resolve() try: sys.path.append(KSFT_DIR.as_posix()) + from net.lib.py import * from drivers.net.lib.py import * + + # Import one by one to avoid pylint false positives + from net.lib.py import EthtoolFamily, NetdevFamily, NetshaperFamily, \ + NlError, RtnlFamily + from net.lib.py import CmdExitFailure + from net.lib.py import bkg, cmd, defer, ethtool, fd_read_timeout, ip, \ + rand_port, tool, wait_port_listen + from net.lib.py import fd_read_timeout + from net.lib.py import KsftSkipEx, KsftFailEx, KsftXfailEx + from net.lib.py import ksft_disruptive, ksft_exit, ksft_pr, ksft_run, \ + ksft_setup + from net.lib.py import ksft_eq, ksft_ge, ksft_in, ksft_is, ksft_lt, \ + ksft_ne, ksft_not_in, ksft_raises, ksft_true + from net.lib.py import NetNSEnter + from drivers.net.lib.py import GenerateTraffic + from drivers.net.lib.py import NetDrvEnv, NetDrvEpEnv except ModuleNotFoundError as e: ksft_pr("Failed importing `net` library from kernel sources") ksft_pr(str(e)) diff --git a/tools/testing/selftests/drivers/net/lib/py/__init__.py b/tools/testing/selftests/drivers/net/lib/py/__init__.py index 401e70f7f136..9ed1d8f70524 100644 --- a/tools/testing/selftests/drivers/net/lib/py/__init__.py +++ b/tools/testing/selftests/drivers/net/lib/py/__init__.py @@ -7,7 +7,21 @@ KSFT_DIR = (Path(__file__).parent / "../../../..").resolve() try: sys.path.append(KSFT_DIR.as_posix()) + from net.lib.py import * + + # Import one by one to avoid pylint false positives + from net.lib.py import EthtoolFamily, NetdevFamily, NetshaperFamily, \ + NlError, RtnlFamily + from net.lib.py import CmdExitFailure + from net.lib.py import bkg, cmd, defer, ethtool, fd_read_timeout, ip, \ + rand_port, tool, wait_port_listen + from net.lib.py import fd_read_timeout + from net.lib.py import KsftSkipEx, KsftFailEx, KsftXfailEx + from net.lib.py import ksft_disruptive, ksft_exit, ksft_pr, ksft_run, \ + ksft_setup + from net.lib.py import ksft_eq, ksft_ge, ksft_in, ksft_is, ksft_lt, \ + ksft_ne, ksft_not_in, ksft_raises, ksft_true except ModuleNotFoundError as e: ksft_pr("Failed importing `net` library from kernel sources") ksft_pr(str(e)) -- 2.49.0

6 months

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[PATCH] selftests: ir_decoder: Convert header comment to proper multi-line block

by Abdelrahman Fekry

The test file for the IR decoder used single-line comments at the top to document its purpose and licensing, which is inconsistent with the style used throughout the Linux kernel. in this patch i converted the file header to a proper multi-line comment block (/*) that aligns with standard kernel practices. This improves readability, consistency across selftests, and ensures the license and documentation are clearly visible in a familiar format. No functional changes have been made. Signed-off-by: Abdelrahman Fekry <Abdelrahmanfekry375(a)gmail.com> --- tools/testing/selftests/ir/ir_loopback.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/ir/ir_loopback.c b/tools/testing/selftests/ir/ir_loopback.c index f4a15cbdd5ea..2de4a6296f35 100644 --- a/tools/testing/selftests/ir/ir_loopback.c +++ b/tools/testing/selftests/ir/ir_loopback.c @@ -1,14 +1,15 @@ // SPDX-License-Identifier: GPL-2.0 -// test ir decoder -// -// Copyright (C) 2018 Sean Young <sean(a)mess.org> - -// When sending LIRC_MODE_SCANCODE, the IR will be encoded. rc-loopback -// will send this IR to the receiver side, where we try to read the decoded -// IR. Decoding happens in a separate kernel thread, so we will need to -// wait until that is scheduled, hence we use poll to check for read -// readiness. - +/* Copyright (C) 2018 Sean Young <sean(a)mess.org> + * + * Selftest for IR decoder + * + * + * When sending LIRC_MODE_SCANCODE, the IR will be encoded. rc-loopback + * will send this IR to the receiver side, where we try to read the decoded + * IR. Decoding happens in a separate kernel thread, so we will need to + * wait until that is scheduled, hence we use poll to check for read + * readiness. +*/ #include <linux/lirc.h> #include <errno.h> #include <stdio.h> -- 2.25.1

6 months

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[PATCH v6 0/2] x86/fred: Prevent immediate repeat of single step trap on return from SIGTRAP handler

by Xin Li (Intel)

IDT event delivery has a debug hole in which it does not generate #DB upon returning to userspace before the first userspace instruction is executed if the Trap Flag (TF) is set. FRED closes this hole by introducing a software event flag, i.e., bit 17 of the augmented SS: if the bit is set and ERETU would result in RFLAGS.TF = 1, a single-step trap will be pending upon completion of ERETU. However I overlooked properly setting and clearing the bit in different situations. Thus when FRED is enabled, if the Trap Flag (TF) is set without an external debugger attached, it can lead to an infinite loop in the SIGTRAP handler. To avoid this, the software event flag in the augmented SS must be cleared, ensuring that no single-step trap remains pending when ERETU completes. This patch set combines the fix [1] and its corresponding selftest [2] (requested by Dave Hansen) into one patch set. [1] https://lore.kernel.org/lkml/20250523050153.3308237-1-xin@zytor.com/ [2] https://lore.kernel.org/lkml/20250530230707.2528916-1-xin@zytor.com/ This patch set is based on tip/x86/urgent branch. Link to v5 of this patch set: https://lore.kernel.org/lkml/20250606174528.1004756-1-xin@zytor.com/ Changes in v6: *) Replace a "sub $128, %rsp" with "add $-128, %rsp" (hpa). *) Declared loop_count_on_same_ip inside sigtrap() (Sohil). *) s/sigtrap/SIGTRAP (Sohil). *) Add TB from Sohil to the first patch. Xin Li (Intel) (2): x86/fred/signal: Prevent immediate repeat of single step trap on return from SIGTRAP handler selftests/x86: Add a test to detect infinite SIGTRAP handler loop arch/x86/include/asm/sighandling.h | 22 +++++ arch/x86/kernel/signal_32.c | 4 + arch/x86/kernel/signal_64.c | 4 + tools/testing/selftests/x86/Makefile | 2 +- tools/testing/selftests/x86/sigtrap_loop.c | 101 +++++++++++++++++++++ 5 files changed, 132 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/x86/sigtrap_loop.c base-commit: dd2922dcfaa3296846265e113309e5f7f138839f -- 2.49.0

6 months

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[PATCH 0/2] kselftest/arm64: Add coverage for the interaction of vfork() and GCS

by Mark Brown

I had cause to look at the vfork() support for GCS and realised that we don't have any direct test coverage, this series does so by adding vfork() to nolibc and then using that in basic-gcs to provide some simple vfork() coverage. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Mark Brown (2): tools/nolibc: Provide vfork() kselftest/arm64: Add a test for vfork() with GCS tools/include/nolibc/sys.h | 29 ++++++++++++ tools/testing/selftests/arm64/gcs/basic-gcs.c | 63 +++++++++++++++++++++++++++ 2 files changed, 92 insertions(+) --- base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494 change-id: 20250528-arm64-gcs-vfork-exit-4a7daf7652ee Best regards, -- Mark Brown <broonie(a)kernel.org>

6 months

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[PATCH v2] selftests/bpf: Validate UDP length in cls_redirect test

by Suchit Karunakaran

From: Suchit <suchitkarunakaran(a)gmail.com> Add validation step to ensure that the UDP payload is long enough to contain the expected GUE and UNIGUE encapsulation headers Signed-off-by: Suchit <suchitkarunakaran(a)gmail.com> --- Changes since v2: - Rebase tools/testing/selftests/bpf/progs/test_cls_redirect.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/progs/test_cls_redirect.c b/tools/testing/selftests/bpf/progs/test_cls_redirect.c index f344c6835e84..c1d2eaee2e77 100644 --- a/tools/testing/selftests/bpf/progs/test_cls_redirect.c +++ b/tools/testing/selftests/bpf/progs/test_cls_redirect.c @@ -978,7 +978,14 @@ int cls_redirect(struct __sk_buff *skb) return TC_ACT_OK; } - /* TODO Check UDP length? */ + uint16_t udp_len = bpf_ntohs(encap->udp.len); + uint16_t min_encap_len = sizeof(encap->udp) + sizeof(encap->gue) + sizeof(encap->unigue); + + if (udp_len < min_encap_len) { + metrics->errors_total_malformed_encapsulation++; + return TC_ACT_SHOT; + } + if (encap->udp.dest != ENCAPSULATION_PORT) { return TC_ACT_OK; } -- 2.49.0

6 months, 1 week

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[PATCH v5 0/2] x86/fred: Prevent immediate repeat of single step trap on return from SIGTRAP handler

by Xin Li (Intel)

IDT event delivery has a debug hole in which it does not generate #DB upon returning to userspace before the first userspace instruction is executed if the Trap Flag (TF) is set. FRED closes this hole by introducing a software event flag, i.e., bit 17 of the augmented SS: if the bit is set and ERETU would result in RFLAGS.TF = 1, a single-step trap will be pending upon completion of ERETU. However I overlooked properly setting and clearing the bit in different situations. Thus when FRED is enabled, if the Trap Flag (TF) is set without an external debugger attached, it can lead to an infinite loop in the SIGTRAP handler. To avoid this, the software event flag in the augmented SS must be cleared, ensuring that no single-step trap remains pending when ERETU completes. This patch set combines the fix [1] and its corresponding selftest [2] (requested by Dave Hansen) into one patch set. [1] https://lore.kernel.org/lkml/20250523050153.3308237-1-xin@zytor.com/ [2] https://lore.kernel.org/lkml/20250530230707.2528916-1-xin@zytor.com/ This patch set is based on tip/x86/urgent branch as of today. Link to v4 of this patch set: https://lore.kernel.org/lkml/20250605181020.590459-1-xin@zytor.com/ Changes in v5: *) Accurately rephrase the shortlog (hpa). *) Do "sub $-128, %rsp" rather than "add $128, %rsp", which is more efficient in code size (hpa). *) Add TB from Sohil. *) Add Cc: stable(a)vger.kernel.org to all patches. Xin Li (Intel) (2): x86/fred/signal: Prevent immediate repeat of single step trap on return from SIGTRAP handler selftests/x86: Add a test to detect infinite sigtrap handler loop arch/x86/include/asm/sighandling.h | 22 +++++ arch/x86/kernel/signal_32.c | 4 + arch/x86/kernel/signal_64.c | 4 + tools/testing/selftests/x86/Makefile | 2 +- tools/testing/selftests/x86/sigtrap_loop.c | 98 ++++++++++++++++++++++ 5 files changed, 129 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/x86/sigtrap_loop.c base-commit: dd2922dcfaa3296846265e113309e5f7f138839f -- 2.49.0

6 months, 1 week

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[PATCH RFC bpf-next 0/4] bpf, arm64: support up to 12 arguments

by Alexis Lothoré (eBPF Foundation)

Hello, this series is a revival of Xu Kuhoai's work to enable larger arguments count for BPF programs on ARM64 ([1]). His initial series received some positive feedback, but lacked some specific case handling around arguments alignment (see AAPCS64 C.14 rule in section 6.8.2, [2]). There as been another attempt from Puranjay Mohan, which was unfortunately missing the same thing ([3]). Since there has been some time between those series and this new one, I chose to send it as a new series rather than a new revision of the existing series. To support the increased argument counts and arguments larger than registers size (eg: structures), the trampoline does the following: - for bpf programs: arguments are retrieved from both registers and the function stack, and pushed in the trampoline stack as an array of u64 to generate the programs context. It is then passed by pointer to the bpf programs - when the trampoline is in charge of calling the original function: it restores the registers content, and generates a new stack layout for the additional arguments that do not fit in registers. This new attempt is based on Xu's series and aims to handle the missing alignment concern raised in the reviews discussions. The main novelties are then around arguments alignments: - the first commit is exposing some new info in the BTF function model passed to the JIT compiler to allow it to deduce the needed alignment when configuring the trampoline stack - the second commit is taken from Xu's series, and received the following modifications: - the calc_aux_args computes an expected alignment for each argument - the calc_aux_args computes two different stack space sizes: the one needed to store the bpf programs context, and the original function stacked arguments (which needs alignment). Those stack sizes are in bytes instead of "slots" - when saving/restoring arguments for bpf program or for the original function, make sure to align the load/store accordingly, when relevant - a few typos fixes and some rewording, raised by the review on the original series - the last commit introduces some explicit tests that ensure that the needed alignment is enforced by the trampoline I marked the series as RFC because it appears that the new tests trigger some failures in CI on x86 and s390, despite the series not touching any code related to those architectures. Some very early investigation/gdb debugging on the x86 side seems to hint that it could be related to the same missing alignment too (based on section 3.2.3 in [4], and so the x86 trampoline would need the same alignment handling ?). For s390 it looks less clear, as all values captured from the bpf test program are set to 0 in the CI output, and I don't have the proper setup yet to check the low level details. I am tempted to isolate those new tests (which were actually useful to spot real issues while tuning the ARM64 trampoline) and add them to the relevant DENYLIST files for x86/s390, but I guess this is not the right direction, so I would gladly take a second opinion on this. [1] https://lore.kernel.org/all/20230917150752.69612-1-xukuohai@huaweicloud.com… [2] https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst#id82 [3] https://lore.kernel.org/bpf/20240705125336.46820-1-puranjay@kernel.org/ [4] https://refspecs.linuxbase.org/elf/x86_64-abi-0.99.pdf Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore(a)bootlin.com> --- Alexis Lothoré (eBPF Foundation) (3): bpf: add struct largest member size in func model bpf/selftests: add tests to validate proper arguments alignment on ARM64 bpf/selftests: enable tracing tests for ARM64 Xu Kuohai (1): bpf, arm64: Support up to 12 function arguments arch/arm64/net/bpf_jit_comp.c | 235 ++++++++++++++++----- include/linux/bpf.h | 1 + kernel/bpf/btf.c | 25 +++ tools/testing/selftests/bpf/DENYLIST.aarch64 | 3 - .../selftests/bpf/prog_tests/tracing_struct.c | 23 ++ tools/testing/selftests/bpf/progs/tracing_struct.c | 10 +- .../selftests/bpf/progs/tracing_struct_many_args.c | 67 ++++++ .../testing/selftests/bpf/test_kmods/bpf_testmod.c | 50 +++++ 8 files changed, 357 insertions(+), 57 deletions(-) --- base-commit: 91e7eb701b4bc389e7ddfd80ef6e82d1a6d2d368 change-id: 20250220-many_args_arm64-8bd3747e6948 Best regards, -- Alexis Lothoré, Bootlin Embedded Linux and Kernel engineering https://bootlin.com

6 months, 1 week

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