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[PATCH 6.6] ipv6: Fix soft lockups in fib6_select_path under high next hop churn

by Rajani kantha

From: Omid Ehtemam-Haghighi <omid.ehtemamhaghighi(a)menlosecurity.com> [ Upstream commit d9ccb18f83ea2bb654289b6ecf014fd267cc988b ] Soft lockups have been observed on a cluster of Linux-based edge routers located in a highly dynamic environment. Using the `bird` service, these routers continuously update BGP-advertised routes due to frequently changing nexthop destinations, while also managing significant IPv6 traffic. The lockups occur during the traversal of the multipath circular linked-list in the `fib6_select_path` function, particularly while iterating through the siblings in the list. The issue typically arises when the nodes of the linked list are unexpectedly deleted concurrently on a different core—indicated by their 'next' and 'previous' elements pointing back to the node itself and their reference count dropping to zero. This results in an infinite loop, leading to a soft lockup that triggers a system panic via the watchdog timer. Apply RCU primitives in the problematic code sections to resolve the issue. Where necessary, update the references to fib6_siblings to annotate or use the RCU APIs. Include a test script that reproduces the issue. The script periodically updates the routing table while generating a heavy load of outgoing IPv6 traffic through multiple iperf3 clients. It consistently induces infinite soft lockups within a couple of minutes. Kernel log: 0 [ffffbd13003e8d30] machine_kexec at ffffffff8ceaf3eb 1 [ffffbd13003e8d90] __crash_kexec at ffffffff8d0120e3 2 [ffffbd13003e8e58] panic at ffffffff8cef65d4 3 [ffffbd13003e8ed8] watchdog_timer_fn at ffffffff8d05cb03 4 [ffffbd13003e8f08] __hrtimer_run_queues at ffffffff8cfec62f 5 [ffffbd13003e8f70] hrtimer_interrupt at ffffffff8cfed756 6 [ffffbd13003e8fd0] __sysvec_apic_timer_interrupt at ffffffff8cea01af 7 [ffffbd13003e8ff0] sysvec_apic_timer_interrupt at ffffffff8df1b83d -- <IRQ stack> -- 8 [ffffbd13003d3708] asm_sysvec_apic_timer_interrupt at ffffffff8e000ecb [exception RIP: fib6_select_path+299] RIP: ffffffff8ddafe7b RSP: ffffbd13003d37b8 RFLAGS: 00000287 RAX: ffff975850b43600 RBX: ffff975850b40200 RCX: 0000000000000000 RDX: 000000003fffffff RSI: 0000000051d383e4 RDI: ffff975850b43618 RBP: ffffbd13003d3800 R8: 0000000000000000 R9: ffff975850b40200 R10: 0000000000000000 R11: 0000000000000000 R12: ffffbd13003d3830 R13: ffff975850b436a8 R14: ffff975850b43600 R15: 0000000000000007 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 9 [ffffbd13003d3808] ip6_pol_route at ffffffff8ddb030c 10 [ffffbd13003d3888] ip6_pol_route_input at ffffffff8ddb068c 11 [ffffbd13003d3898] fib6_rule_lookup at ffffffff8ddf02b5 12 [ffffbd13003d3928] ip6_route_input at ffffffff8ddb0f47 13 [ffffbd13003d3a18] ip6_rcv_finish_core.constprop.0 at ffffffff8dd950d0 14 [ffffbd13003d3a30] ip6_list_rcv_finish.constprop.0 at ffffffff8dd96274 15 [ffffbd13003d3a98] ip6_sublist_rcv at ffffffff8dd96474 16 [ffffbd13003d3af8] ipv6_list_rcv at ffffffff8dd96615 17 [ffffbd13003d3b60] __netif_receive_skb_list_core at ffffffff8dc16fec 18 [ffffbd13003d3be0] netif_receive_skb_list_internal at ffffffff8dc176b3 19 [ffffbd13003d3c50] napi_gro_receive at ffffffff8dc565b9 20 [ffffbd13003d3c80] ice_receive_skb at ffffffffc087e4f5 [ice] 21 [ffffbd13003d3c90] ice_clean_rx_irq at ffffffffc0881b80 [ice] 22 [ffffbd13003d3d20] ice_napi_poll at ffffffffc088232f [ice] 23 [ffffbd13003d3d80] __napi_poll at ffffffff8dc18000 24 [ffffbd13003d3db8] net_rx_action at ffffffff8dc18581 25 [ffffbd13003d3e40] __do_softirq at ffffffff8df352e9 26 [ffffbd13003d3eb0] run_ksoftirqd at ffffffff8ceffe47 27 [ffffbd13003d3ec0] smpboot_thread_fn at ffffffff8cf36a30 28 [ffffbd13003d3ee8] kthread at ffffffff8cf2b39f 29 [ffffbd13003d3f28] ret_from_fork at ffffffff8ce5fa64 30 [ffffbd13003d3f50] ret_from_fork_asm at ffffffff8ce03cbb Fixes: 66f5d6ce53e6 ("ipv6: replace rwlock with rcu and spinlock in fib6_table") Reported-by: Adrian Oliver <kernel(a)aoliver.ca> Signed-off-by: Omid Ehtemam-Haghighi <omid.ehtemamhaghighi(a)menlosecurity.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Ido Schimmel <idosch(a)idosch.org> Cc: Kuniyuki Iwashima <kuniyu(a)amazon.com> Cc: Simon Horman <horms(a)kernel.org> Reviewed-by: David Ahern <dsahern(a)kernel.org> Link: https://patch.msgid.link/20241106010236.1239299-1-omid.ehtemamhaghighi@menl… Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> Signed-off-by: Rajani Kantha <rajanikantha(a)engineer.com> --- net/ipv6/ip6_fib.c | 8 +- net/ipv6/route.c | 45 ++- tools/testing/selftests/net/Makefile | 1 + .../net/ipv6_route_update_soft_lockup.sh | 262 ++++++++++++++++++ 4 files changed, 297 insertions(+), 19 deletions(-) create mode 100755 tools/testing/selftests/net/ipv6_route_update_soft_lockup.sh diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index afa9073567dc..023ac39041a2 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -1179,8 +1179,8 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, while (sibling) { if (sibling->fib6_metric == rt->fib6_metric && rt6_qualify_for_ecmp(sibling)) { - list_add_tail(&rt->fib6_siblings, - &sibling->fib6_siblings); + list_add_tail_rcu(&rt->fib6_siblings, + &sibling->fib6_siblings); break; } sibling = rcu_dereference_protected(sibling->fib6_next, @@ -1241,7 +1241,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, fib6_siblings) sibling->fib6_nsiblings--; rt->fib6_nsiblings = 0; - list_del_init(&rt->fib6_siblings); + list_del_rcu(&rt->fib6_siblings); rt6_multipath_rebalance(next_sibling); return err; } @@ -1954,7 +1954,7 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn, &rt->fib6_siblings, fib6_siblings) sibling->fib6_nsiblings--; rt->fib6_nsiblings = 0; - list_del_init(&rt->fib6_siblings); + list_del_rcu(&rt->fib6_siblings); rt6_multipath_rebalance(next_sibling); } diff --git a/net/ipv6/route.c b/net/ipv6/route.c index fc5c53462025..c5cee40a658b 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -418,8 +418,8 @@ void fib6_select_path(const struct net *net, struct fib6_result *res, struct flowi6 *fl6, int oif, bool have_oif_match, const struct sk_buff *skb, int strict) { - struct fib6_info *sibling, *next_sibling; struct fib6_info *match = res->f6i; + struct fib6_info *sibling; if (!match->nh && (!match->fib6_nsiblings || have_oif_match)) goto out; @@ -445,8 +445,8 @@ void fib6_select_path(const struct net *net, struct fib6_result *res, if (fl6->mp_hash <= atomic_read(&match->fib6_nh->fib_nh_upper_bound)) goto out; - list_for_each_entry_safe(sibling, next_sibling, &match->fib6_siblings, - fib6_siblings) { + list_for_each_entry_rcu(sibling, &match->fib6_siblings, + fib6_siblings) { const struct fib6_nh *nh = sibling->fib6_nh; int nh_upper_bound; @@ -5186,14 +5186,18 @@ static void ip6_route_mpath_notify(struct fib6_info *rt, * nexthop. Since sibling routes are always added at the end of * the list, find the first sibling of the last route appended */ + rcu_read_lock(); + if ((nlflags & NLM_F_APPEND) && rt_last && rt_last->fib6_nsiblings) { - rt = list_first_entry(&rt_last->fib6_siblings, - struct fib6_info, - fib6_siblings); + rt = list_first_or_null_rcu(&rt_last->fib6_siblings, + struct fib6_info, + fib6_siblings); } if (rt) inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags); + + rcu_read_unlock(); } static bool ip6_route_mpath_should_notify(const struct fib6_info *rt) @@ -5538,17 +5542,21 @@ static size_t rt6_nlmsg_size(struct fib6_info *f6i) nexthop_for_each_fib6_nh(f6i->nh, rt6_nh_nlmsg_size, &nexthop_len); } else { - struct fib6_info *sibling, *next_sibling; struct fib6_nh *nh = f6i->fib6_nh; + struct fib6_info *sibling; nexthop_len = 0; if (f6i->fib6_nsiblings) { rt6_nh_nlmsg_size(nh, &nexthop_len); - list_for_each_entry_safe(sibling, next_sibling, - &f6i->fib6_siblings, fib6_siblings) { + rcu_read_lock(); + + list_for_each_entry_rcu(sibling, &f6i->fib6_siblings, + fib6_siblings) { rt6_nh_nlmsg_size(sibling->fib6_nh, &nexthop_len); } + + rcu_read_unlock(); } nexthop_len += lwtunnel_get_encap_size(nh->fib_nh_lws); } @@ -5712,7 +5720,7 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb, lwtunnel_fill_encap(skb, dst->lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0) goto nla_put_failure; } else if (rt->fib6_nsiblings) { - struct fib6_info *sibling, *next_sibling; + struct fib6_info *sibling; struct nlattr *mp; mp = nla_nest_start_noflag(skb, RTA_MULTIPATH); @@ -5724,14 +5732,21 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb, 0) < 0) goto nla_put_failure; - list_for_each_entry_safe(sibling, next_sibling, - &rt->fib6_siblings, fib6_siblings) { + rcu_read_lock(); + + list_for_each_entry_rcu(sibling, &rt->fib6_siblings, + fib6_siblings) { if (fib_add_nexthop(skb, &sibling->fib6_nh->nh_common, sibling->fib6_nh->fib_nh_weight, - AF_INET6, 0) < 0) + AF_INET6, 0) < 0) { + rcu_read_unlock(); + goto nla_put_failure; + } } + rcu_read_unlock(); + nla_nest_end(skb, mp); } else if (rt->nh) { if (nla_put_u32(skb, RTA_NH_ID, rt->nh->id)) @@ -6168,7 +6183,7 @@ void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info, err = -ENOBUFS; seq = info->nlh ? info->nlh->nlmsg_seq : 0; - skb = nlmsg_new(rt6_nlmsg_size(rt), gfp_any()); + skb = nlmsg_new(rt6_nlmsg_size(rt), GFP_ATOMIC); if (!skb) goto errout; @@ -6181,7 +6196,7 @@ void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info, goto errout; } rtnl_notify(skb, net, info->portid, RTNLGRP_IPV6_ROUTE, - info->nlh, gfp_any()); + info->nlh, GFP_ATOMIC); return; errout: if (err < 0) diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index 91a48efb140b..efaf0e0bc459 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -91,6 +91,7 @@ TEST_PROGS += test_vxlan_mdb.sh TEST_PROGS += test_bridge_neigh_suppress.sh TEST_PROGS += test_vxlan_nolocalbypass.sh TEST_PROGS += test_bridge_backup_port.sh +TEST_PROGS += ipv6_route_update_soft_lockup.sh TEST_FILES := settings TEST_FILES += in_netns.sh lib.sh net_helper.sh setup_loopback.sh setup_veth.sh diff --git a/tools/testing/selftests/net/ipv6_route_update_soft_lockup.sh b/tools/testing/selftests/net/ipv6_route_update_soft_lockup.sh new file mode 100755 index 000000000000..a6b2b1f9c641 --- /dev/null +++ b/tools/testing/selftests/net/ipv6_route_update_soft_lockup.sh @@ -0,0 +1,262 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# Testing for potential kernel soft lockup during IPv6 routing table +# refresh under heavy outgoing IPv6 traffic. If a kernel soft lockup +# occurs, a kernel panic will be triggered to prevent associated issues. +# +# +# Test Environment Layout +# +# ┌----------------┐ ┌----------------┐ +# | SOURCE_NS | | SINK_NS | +# | NAMESPACE | | NAMESPACE | +# |(iperf3 clients)| |(iperf3 servers)| +# | | | | +# | | | | +# | ┌-----------| nexthops |---------┐ | +# | |veth_source|<--------------------------------------->|veth_sink|<┐ | +# | └-----------|2001:0DB8:1::0:1/96 2001:0DB8:1::1:1/96 |---------┘ | | +# | | ^ 2001:0DB8:1::1:2/96 | | | +# | | . . | fwd | | +# | ┌---------┐ | . . | | | +# | | IPv6 | | . . | V | +# | | routing | | . 2001:0DB8:1::1:80/96| ┌-----┐ | +# | | table | | . | | lo | | +# | | nexthop | | . └--------┴-----┴-┘ +# | | update | | ............................> 2001:0DB8:2::1:1/128 +# | └-------- ┘ | +# └----------------┘ +# +# The test script sets up two network namespaces, source_ns and sink_ns, +# connected via a veth link. Within source_ns, it continuously updates the +# IPv6 routing table by flushing and inserting IPV6_NEXTHOP_ADDR_COUNT nexthop +# IPs destined for SINK_LOOPBACK_IP_ADDR in sink_ns. This refresh occurs at a +# rate of 1/ROUTING_TABLE_REFRESH_PERIOD per second for TEST_DURATION seconds. +# +# Simultaneously, multiple iperf3 clients within source_ns generate heavy +# outgoing IPv6 traffic. Each client is assigned a unique port number starting +# at 5000 and incrementing sequentially. Each client targets a unique iperf3 +# server running in sink_ns, connected to the SINK_LOOPBACK_IFACE interface +# using the same port number. +# +# The number of iperf3 servers and clients is set to half of the total +# available cores on each machine. +# +# NOTE: We have tested this script on machines with various CPU specifications, +# ranging from lower to higher performance as listed below. The test script +# effectively triggered a kernel soft lockup on machines running an unpatched +# kernel in under a minute: +# +# - 1x Intel Xeon E-2278G 8-Core Processor @ 3.40GHz +# - 1x Intel Xeon E-2378G Processor 8-Core @ 2.80GHz +# - 1x AMD EPYC 7401P 24-Core Processor @ 2.00GHz +# - 1x AMD EPYC 7402P 24-Core Processor @ 2.80GHz +# - 2x Intel Xeon Gold 5120 14-Core Processor @ 2.20GHz +# - 1x Ampere Altra Q80-30 80-Core Processor @ 3.00GHz +# - 2x Intel Xeon Gold 5120 14-Core Processor @ 2.20GHz +# - 2x Intel Xeon Silver 4214 24-Core Processor @ 2.20GHz +# - 1x AMD EPYC 7502P 32-Core @ 2.50GHz +# - 1x Intel Xeon Gold 6314U 32-Core Processor @ 2.30GHz +# - 2x Intel Xeon Gold 6338 32-Core Processor @ 2.00GHz +# +# On less performant machines, you may need to increase the TEST_DURATION +# parameter to enhance the likelihood of encountering a race condition leading +# to a kernel soft lockup and avoid a false negative result. +# +# NOTE: The test may not produce the expected result in virtualized +# environments (e.g., qemu) due to differences in timing and CPU handling, +# which can affect the conditions needed to trigger a soft lockup. + +source lib.sh +source net_helper.sh + +TEST_DURATION=300 +ROUTING_TABLE_REFRESH_PERIOD=0.01 + +IPERF3_BITRATE="300m" + + +IPV6_NEXTHOP_ADDR_COUNT="128" +IPV6_NEXTHOP_ADDR_MASK="96" +IPV6_NEXTHOP_PREFIX="2001:0DB8:1" + + +SOURCE_TEST_IFACE="veth_source" +SOURCE_TEST_IP_ADDR="2001:0DB8:1::0:1/96" + +SINK_TEST_IFACE="veth_sink" +# ${SINK_TEST_IFACE} is populated with the following range of IPv6 addresses: +# 2001:0DB8:1::1:1 to 2001:0DB8:1::1:${IPV6_NEXTHOP_ADDR_COUNT} +SINK_LOOPBACK_IFACE="lo" +SINK_LOOPBACK_IP_MASK="128" +SINK_LOOPBACK_IP_ADDR="2001:0DB8:2::1:1" + +nexthop_ip_list="" +termination_signal="" +kernel_softlokup_panic_prev_val="" + +terminate_ns_processes_by_pattern() { + local ns=$1 + local pattern=$2 + + for pid in $(ip netns pids ${ns}); do + [ -e /proc/$pid/cmdline ] && grep -qe "${pattern}" /proc/$pid/cmdline && kill -9 $pid + done +} + +cleanup() { + echo "info: cleaning up namespaces and terminating all processes within them..." + + + # Terminate iperf3 instances running in the source_ns. To avoid race + # conditions, first iterate over the PIDs and terminate those + # associated with the bash shells running the + # `while true; do iperf3 -c ...; done` loops. In a second iteration, + # terminate the individual `iperf3 -c ...` instances. + terminate_ns_processes_by_pattern ${source_ns} while + terminate_ns_processes_by_pattern ${source_ns} iperf3 + + # Repeat the same process for sink_ns + terminate_ns_processes_by_pattern ${sink_ns} while + terminate_ns_processes_by_pattern ${sink_ns} iperf3 + + # Check if any iperf3 instances are still running. This could happen + # if a core has entered an infinite loop and the timeout for detecting + # the soft lockup has not expired, but either the test interval has + # already elapsed or the test was terminated manually (e.g., with ^C) + for pid in $(ip netns pids ${source_ns}); do + if [ -e /proc/$pid/cmdline ] && grep -qe 'iperf3' /proc/$pid/cmdline; then + echo "FAIL: unable to terminate some iperf3 instances. Soft lockup is underway. A kernel panic is on the way!" + exit ${ksft_fail} + fi + done + + if [ "$termination_signal" == "SIGINT" ]; then + echo "SKIP: Termination due to ^C (SIGINT)" + elif [ "$termination_signal" == "SIGALRM" ]; then + echo "PASS: No kernel soft lockup occurred during this ${TEST_DURATION} second test" + fi + + cleanup_ns ${source_ns} ${sink_ns} + + sysctl -qw kernel.softlockup_panic=${kernel_softlokup_panic_prev_val} +} + +setup_prepare() { + setup_ns source_ns sink_ns + + ip -n ${source_ns} link add name ${SOURCE_TEST_IFACE} type veth peer name ${SINK_TEST_IFACE} netns ${sink_ns} + + # Setting up the Source namespace + ip -n ${source_ns} addr add ${SOURCE_TEST_IP_ADDR} dev ${SOURCE_TEST_IFACE} + ip -n ${source_ns} link set dev ${SOURCE_TEST_IFACE} qlen 10000 + ip -n ${source_ns} link set dev ${SOURCE_TEST_IFACE} up + ip netns exec ${source_ns} sysctl -qw net.ipv6.fib_multipath_hash_policy=1 + + # Setting up the Sink namespace + ip -n ${sink_ns} addr add ${SINK_LOOPBACK_IP_ADDR}/${SINK_LOOPBACK_IP_MASK} dev ${SINK_LOOPBACK_IFACE} + ip -n ${sink_ns} link set dev ${SINK_LOOPBACK_IFACE} up + ip netns exec ${sink_ns} sysctl -qw net.ipv6.conf.${SINK_LOOPBACK_IFACE}.forwarding=1 + + ip -n ${sink_ns} link set ${SINK_TEST_IFACE} up + ip netns exec ${sink_ns} sysctl -qw net.ipv6.conf.${SINK_TEST_IFACE}.forwarding=1 + + + # Populate nexthop IPv6 addresses on the test interface in the sink_ns + echo "info: populating ${IPV6_NEXTHOP_ADDR_COUNT} IPv6 addresses on the ${SINK_TEST_IFACE} interface ..." + for IP in $(seq 1 ${IPV6_NEXTHOP_ADDR_COUNT}); do + ip -n ${sink_ns} addr add ${IPV6_NEXTHOP_PREFIX}::$(printf "1:%x" "${IP}")/${IPV6_NEXTHOP_ADDR_MASK} dev ${SINK_TEST_IFACE}; + done + + # Preparing list of nexthops + for IP in $(seq 1 ${IPV6_NEXTHOP_ADDR_COUNT}); do + nexthop_ip_list=$nexthop_ip_list" nexthop via ${IPV6_NEXTHOP_PREFIX}::$(printf "1:%x" $IP) dev ${SOURCE_TEST_IFACE} weight 1" + done +} + + +test_soft_lockup_during_routing_table_refresh() { + # Start num_of_iperf_servers iperf3 servers in the sink_ns namespace, + # each listening on ports starting at 5001 and incrementing + # sequentially. Since iperf3 instances may terminate unexpectedly, a + # while loop is used to automatically restart them in such cases. + echo "info: starting ${num_of_iperf_servers} iperf3 servers in the sink_ns namespace ..." + for i in $(seq 1 ${num_of_iperf_servers}); do + cmd="iperf3 --bind ${SINK_LOOPBACK_IP_ADDR} -s -p $(printf '5%03d' ${i}) --rcv-timeout 200 &>/dev/null" + ip netns exec ${sink_ns} bash -c "while true; do ${cmd}; done &" &>/dev/null + done + + # Wait for the iperf3 servers to be ready + for i in $(seq ${num_of_iperf_servers}); do + port=$(printf '5%03d' ${i}); + wait_local_port_listen ${sink_ns} ${port} tcp + done + + # Continuously refresh the routing table in the background within + # the source_ns namespace + ip netns exec ${source_ns} bash -c " + while \$(ip netns list | grep -q ${source_ns}); do + ip -6 route add ${SINK_LOOPBACK_IP_ADDR}/${SINK_LOOPBACK_IP_MASK} ${nexthop_ip_list}; + sleep ${ROUTING_TABLE_REFRESH_PERIOD}; + ip -6 route delete ${SINK_LOOPBACK_IP_ADDR}/${SINK_LOOPBACK_IP_MASK}; + done &" + + # Start num_of_iperf_servers iperf3 clients in the source_ns namespace, + # each sending TCP traffic on sequential ports starting at 5001. + # Since iperf3 instances may terminate unexpectedly (e.g., if the route + # to the server is deleted in the background during a route refresh), a + # while loop is used to automatically restart them in such cases. + echo "info: starting ${num_of_iperf_servers} iperf3 clients in the source_ns namespace ..." + for i in $(seq 1 ${num_of_iperf_servers}); do + cmd="iperf3 -c ${SINK_LOOPBACK_IP_ADDR} -p $(printf '5%03d' ${i}) --length 64 --bitrate ${IPERF3_BITRATE} -t 0 --connect-timeout 150 &>/dev/null" + ip netns exec ${source_ns} bash -c "while true; do ${cmd}; done &" &>/dev/null + done + + echo "info: IPv6 routing table is being updated at the rate of $(echo "1/${ROUTING_TABLE_REFRESH_PERIOD}" | bc)/s for ${TEST_DURATION} seconds ..." + echo "info: A kernel soft lockup, if detected, results in a kernel panic!" + + wait +} + +# Make sure 'iperf3' is installed, skip the test otherwise +if [ ! -x "$(command -v "iperf3")" ]; then + echo "SKIP: 'iperf3' is not installed. Skipping the test." + exit ${ksft_skip} +fi + +# Determine the number of cores on the machine +num_of_iperf_servers=$(( $(nproc)/2 )) + +# Check if we are running on a multi-core machine, skip the test otherwise +if [ "${num_of_iperf_servers}" -eq 0 ]; then + echo "SKIP: This test is not valid on a single core machine!" + exit ${ksft_skip} +fi + +# Since the kernel soft lockup we're testing causes at least one core to enter +# an infinite loop, destabilizing the host and likely affecting subsequent +# tests, we trigger a kernel panic instead of reporting a failure and +# continuing +kernel_softlokup_panic_prev_val=$(sysctl -n kernel.softlockup_panic) +sysctl -qw kernel.softlockup_panic=1 + +handle_sigint() { + termination_signal="SIGINT" + cleanup + exit ${ksft_skip} +} + +handle_sigalrm() { + termination_signal="SIGALRM" + cleanup + exit ${ksft_pass} +} + +trap handle_sigint SIGINT +trap handle_sigalrm SIGALRM + +(sleep ${TEST_DURATION} && kill -s SIGALRM $$)& + +setup_prepare +test_soft_lockup_during_routing_table_refresh -- 2.35.3

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[PATCH 5.4.y] m68k: Update ->thread.esp0 before calling syscall_trace() in ret_from_signal

by Finn Thain

From: Al Viro <viro(a)zeniv.linux.org.uk> [ Upstream commit 50e43a57334400668952f8e551c9d87d3ed2dfef ] We get there when sigreturn has performed obscene acts on kernel stack; in particular, the location of pt_regs has shifted. We are about to call syscall_trace(), which might stop for tracer. If that happens, we'd better have task_pt_regs() returning correct result... Fucked-up-by: Al Viro <viro(a)zeniv.linux.org.uk> Fixes: bd6f56a75bb2 ("m68k: Missing syscall_trace() on sigreturn") Signed-off-by: Al Viro <viro(a)zeniv.linux.org.uk> Tested-by: Michael Schmitz <schmitzmic(a)gmail.com> Reviewed-by: Michael Schmitz <schmitzmic(a)gmail.com> Tested-by: Finn Thain <fthain(a)linux-m68k.org> Link: https://lore.kernel.org/r/YP2dMWeV1LkHiOpr@zeniv-ca.linux.org.uk Signed-off-by: Geert Uytterhoeven <geert(a)linux-m68k.org> Signed-off-by: Finn Thain <fthain(a)linux-m68k.org> --- arch/m68k/kernel/entry.S | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S index 417d8f0e8962..0d03b4f2077b 100644 --- a/arch/m68k/kernel/entry.S +++ b/arch/m68k/kernel/entry.S @@ -182,6 +182,8 @@ ENTRY(ret_from_signal) movel %curptr@(TASK_STACK),%a1 tstb %a1@(TINFO_FLAGS+2) jge 1f + lea %sp@(SWITCH_STACK_SIZE),%a1 + movel %a1,%curptr@(TASK_THREAD+THREAD_ESP0) jbsr syscall_trace 1: RESTORE_SWITCH_STACK addql #4,%sp

2 days

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[PATCH 5.10.y] signal/m68k: Use force_sigsegv(SIGSEGV) in fpsp040_die

by Finn Thain

From: "Eric W. Biederman" <ebiederm(a)xmission.com> [ Upstream commit a3616a3c02722d1edb95acc7fceade242f6553ba ] In the fpsp040 code when copyin or copyout fails call force_sigsegv(SIGSEGV) instead of do_exit(SIGSEGV). This solves a couple of problems. Because do_exit embeds the ptrace stop PTRACE_EVENT_EXIT a complete stack frame needs to be present for that to work correctly. There is always the information needed for a ptrace stop where get_signal is called. So exiting with a signal solves the ptrace issue. Further exiting with a signal ensures that all of the threads in a process are killed not just the thread that malfunctioned. Which avoids confusing userspace. To make force_sigsegv(SIGSEGV) work in fpsp040_die modify the code to save all of the registers and jump to ret_from_exception (which ultimately calls get_signal) after fpsp040_die returns. v2: Updated the branches to use gas's pseudo ops that automatically calculate the best branch instruction to use for the purpose. v1: https://lkml.kernel.org/r/87a6m8kgtx.fsf_-_@disp2133 Link: https://lkml.kernel.org/r/87tukghjfs.fsf_-_@disp2133 Acked-by: Geert Uytterhoeven <geert(a)linux-m68k.org> Signed-off-by: "Eric W. Biederman" <ebiederm(a)xmission.com> Signed-off-by: Finn Thain <fthain(a)linux-m68k.org> --- arch/m68k/fpsp040/skeleton.S | 3 ++- arch/m68k/kernel/traps.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/m68k/fpsp040/skeleton.S b/arch/m68k/fpsp040/skeleton.S index 31a9c634c81e..081922c72daa 100644 --- a/arch/m68k/fpsp040/skeleton.S +++ b/arch/m68k/fpsp040/skeleton.S @@ -502,7 +502,8 @@ in_ea: .section .fixup,"ax" .even 1: - jbra fpsp040_die + jbsr fpsp040_die + jbra .Lnotkern .section __ex_table,"a" .align 4 diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c index 35f706d836c5..c6f18dc5884b 100644 --- a/arch/m68k/kernel/traps.c +++ b/arch/m68k/kernel/traps.c @@ -1155,7 +1155,7 @@ asmlinkage void set_esp0(unsigned long ssp) */ asmlinkage void fpsp040_die(void) { - do_exit(SIGSEGV); + force_sigsegv(SIGSEGV); } #ifdef CONFIG_M68KFPU_EMU

2 days

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[PATCH v3] s390/pci: Fix SR-IOV for PFs initially in standby

by Niklas Schnelle

Since commit 25f39d3dcb48 ("s390/pci: Ignore RID for isolated VFs") PFs which are not initially configured but in standby are considered isolated. That is they create only a single function PCI domain. Due to the PCI domains being created on discovery, this means that even if they are configured later on, sibling PFs and their child VFs will not be added to their PCI domain breaking SR-IOV expectations. The reason the referenced commit ignored standby PFs for the creation of multi-function PCI subhierarchies, was to work around a PCI domain renumbering scenario on reboot. The renumbering would occur after removing a previously in standby PF, whose domain number is used for its configured sibling PFs and their child VFs, but which itself remained in standby. When this is followed by a reboot, the sibling PF is used instead to determine the PCI domain number of it and its child VFs. In principle it is not possible to know which standby PFs will be configured later and which may be removed. The PCI domain and root bus are pre-requisites for hotplug slots so the decision of which functions belong to which domain can not be postponed. With the renumbering occurring only in rare circumstances and being generally benign, accept it as an oddity and fix SR-IOV for initially standby PFs simply by allowing them to create PCI domains. Cc: stable(a)vger.kernel.org Reviewed-by: Gerd Bayer <gbayer(a)linux.ibm.com> Fixes: 25f39d3dcb48 ("s390/pci: Ignore RID for isolated VFs") Signed-off-by: Niklas Schnelle <schnelle(a)linux.ibm.com> --- Changes in v3: - Add R-b from Gerd - Add Cc: stable… - Add commas (Sandy) Changes in v2: - Reword commit message --- arch/s390/pci/pci_bus.c | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c index d5ace00d10f04285f899284481f1e426187d4ff4..857afbc4828f0c677f88cc80dd4a5fff104a615a 100644 --- a/arch/s390/pci/pci_bus.c +++ b/arch/s390/pci/pci_bus.c @@ -171,7 +171,6 @@ void zpci_bus_scan_busses(void) static bool zpci_bus_is_multifunction_root(struct zpci_dev *zdev) { return !s390_pci_no_rid && zdev->rid_available && - zpci_is_device_configured(zdev) && !zdev->vfn; } --- base-commit: 6b7afe1a2b6905e42fe45bd7015f20baa856e28e change-id: 20250116-fix_standby_pf-e1d51394e9b3 Best regards, -- Niklas Schnelle

2 days, 1 hour

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[PATCH] powerpc/pseries/iommu: Don't unset window if it was never set

by Shivaprasad G Bhat

On pSeries, when user attempts to use the same vfio container used by different iommu group, the spapr_tce_set_window() returns -EPERM and the subsequent cleanup leads to the below crash. Kernel attempted to read user page (308) - exploit attempt? BUG: Kernel NULL pointer dereference on read at 0x00000308 Faulting instruction address: 0xc0000000001ce358 Oops: Kernel access of bad area, sig: 11 [#1] NIP: c0000000001ce358 LR: c0000000001ce05c CTR: c00000000005add0 <snip> NIP [c0000000001ce358] spapr_tce_unset_window+0x3b8/0x510 LR [c0000000001ce05c] spapr_tce_unset_window+0xbc/0x510 Call Trace: spapr_tce_unset_window+0xbc/0x510 (unreliable) tce_iommu_attach_group+0x24c/0x340 [vfio_iommu_spapr_tce] vfio_container_attach_group+0xec/0x240 [vfio] vfio_group_fops_unl_ioctl+0x548/0xb00 [vfio] sys_ioctl+0x754/0x1580 system_call_exception+0x13c/0x330 system_call_vectored_common+0x15c/0x2ec <snip> --- interrupt: 3000 Fix this by having null check for the tbl passed to the spapr_tce_unset_window(). Fixes: f431a8cde7f1 ("powerpc/iommu: Reimplement the iommu_table_group_ops for pSeries") Cc: stable(a)vger.kernel.org Reported-by: Vaishnavi Bhat <vaish123(a)in.ibm.com> Signed-off-by: Shivaprasad G Bhat <sbhat(a)linux.ibm.com> --- arch/powerpc/platforms/pseries/iommu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index 534cd159e9ab..78b895b568b3 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -2205,6 +2205,9 @@ static long spapr_tce_unset_window(struct iommu_table_group *table_group, int nu const char *win_name; int ret = -ENODEV; + if (!tbl) /* The table was never created OR window was never opened */ + return 0; + mutex_lock(&dma_win_init_mutex); if ((num == 0) && is_default_window_table(table_group, tbl))

2 days, 1 hour

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[PATCH v4 RESEND] powerpc/pseries/eeh: Fix get PE state translation

by Narayana Murty N

The PE Reset State "0" returned by RTAS calls "ibm_read_slot_reset_[state|state2]" indicates that the reset is deactivated and the PE is in a state where MMIO and DMA are allowed. However, the current implementation of "pseries_eeh_get_state()" does not reflect this, causing drivers to incorrectly assume that MMIO and DMA operations cannot be resumed. The userspace drivers as a part of EEH recovery using VFIO ioctls fail to detect when the recovery process is complete. The VFIO_EEH_PE_GET_STATE ioctl does not report the expected EEH_PE_STATE_NORMAL state, preventing userspace drivers from functioning properly on pseries systems. The patch addresses this issue by updating 'pseries_eeh_get_state()' to include "EEH_STATE_MMIO_ENABLED" and "EEH_STATE_DMA_ENABLED" in the result mask for PE Reset State "0". This ensures correct state reporting to the callers, aligning the behavior with the PAPR specification and fixing the bug in EEH recovery for VFIO user workflows. Fixes: 00ba05a12b3c ("powerpc/pseries: Cleanup on pseries_eeh_get_state()") Cc: <stable(a)vger.kernel.org> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list(a)gmail.com> Signed-off-by: Narayana Murty N <nnmlinux(a)linux.ibm.com> --- Changelog: V1:https://lore.kernel.org/all/20241107042027.338065-1-nnmlinux@linux.ibm.c… --added Fixes tag for "powerpc/pseries: Cleanup on pseries_eeh_get_state()". V2:https://lore.kernel.org/stable/20241212075044.10563-1-nnmlinux%40linux.i… --Updated the patch description to include it in the stable kernel tree. V3:https://lore.kernel.org/all/87v7vm8pwz.fsf@gmail.com/ --Updated commit description. --- arch/powerpc/platforms/pseries/eeh_pseries.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/eeh_pseries.c b/arch/powerpc/platforms/pseries/eeh_pseries.c index 1893f66371fa..b12ef382fec7 100644 --- a/arch/powerpc/platforms/pseries/eeh_pseries.c +++ b/arch/powerpc/platforms/pseries/eeh_pseries.c @@ -580,8 +580,10 @@ static int pseries_eeh_get_state(struct eeh_pe *pe, int *delay) switch(rets[0]) { case 0: - result = EEH_STATE_MMIO_ACTIVE | - EEH_STATE_DMA_ACTIVE; + result = EEH_STATE_MMIO_ACTIVE | + EEH_STATE_DMA_ACTIVE | + EEH_STATE_MMIO_ENABLED | + EEH_STATE_DMA_ENABLED; break; case 1: result = EEH_STATE_RESET_ACTIVE | -- 2.47.1

2 days, 1 hour

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[PATCH 0/2] A couple of build fixes for x86 when using GCC 15

by Nathan Chancellor

Hi all, GCC 15 changed the default C standard version from gnu17 to gnu23, which reveals a few places in the kernel where a C standard version was not set, resulting in build failures because bool, true, and false are reserved keywords in C23 [1][2]. Update these places to use the same C standard version as the rest of the kernel, gnu11. [1]: https://lore.kernel.org/4OAhbllK7x4QJGpZjkYjtBYNLd_2whHx9oFiuZcGwtVR4hIzvdu… [2]: https://lore.kernel.org/Z4467umXR2PZ0M1H@tucnak/ --- Nathan Chancellor (2): x86/boot: Use '-std=gnu11' to fix build with GCC 15 efi: libstub: Use '-std=gnu11' to fix build with GCC 15 arch/x86/boot/compressed/Makefile | 1 + drivers/firmware/efi/libstub/Makefile | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) --- base-commit: ffd294d346d185b70e28b1a28abe367bbfe53c04 change-id: 20250121-x86-use-std-consistently-gcc-15-f95146e0050f Best regards, -- Nathan Chancellor <nathan(a)kernel.org>

2 days, 2 hours

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[PATCH] KVM: arm64/sve: Ensure SVE is trapped after guest exit

by Mark Rutland

There is a period of time after returning from a KVM_RUN ioctl where userspace may use SVE without trapping, but the kernel can unexpectedly discard the live SVE state. Eric Auger has observed this causing QEMU crashes where SVE is used by memmove(): https://issues.redhat.com/browse/RHEL-68997 The only state discarded is the user SVE state of the task which issued the KVM_RUN ioctl. Other tasks are unaffected, plain FPSIMD state is unaffected, and kernel state is unaffected. This happens because fpsimd_kvm_prepare() incorrectly manipulates the FPSIMD/SVE state. When the vCPU is loaded, fpsimd_kvm_prepare() unconditionally clears TIF_SVE but does not reconfigure CPACR_EL1.ZEN to trap userspace SVE usage. If the vCPU does not use FPSIMD/SVE and hyp does not save the host's FPSIMD/SVE state, the kernel may return to userspace with TIF_SVE clear while SVE is still enabled in CPACR_EL1.ZEN. Subsequent userspace usage of SVE will not be trapped, and the next save of userspace FPSIMD/SVE state will only store the FPSIMD portion due to TIF_SVE being clear, discarding any SVE state. The broken logic was originally introduced in commit: 93ae6b01bafee8fa ("KVM: arm64: Discard any SVE state when entering KVM guests") ... though at the time fp_user_discard() would reconfigure CPACR_EL1.ZEN to trap subsequent SVE usage, masking the issue until that logic was removed in commit: 8c845e2731041f0f ("arm64/sve: Leave SVE enabled on syscall if we don't context switch") Avoid this issue by reconfiguring CPACR_EL1.ZEN when clearing TIF_SVE. At the same time, add a comment to explain why current->thread.fp_type must be set even though the FPSIMD state is not foreign. A similar issue exists when SME is enabled, and will require further rework. As SME currently depends on BROKEN, a BUILD_BUG() and comment are added for now, and this issue will need to be fixed properly in a follow-up patch. Commit 93ae6b01bafee8fa also introduced an unintended ptrace ABI change. Unconditionally clearing TIF_SVE regardless of whether the state is foreign discards saved SVE state created by ptrace after syscall entry. Avoid this by only clearing TIF_SVE when the FPSIMD/SVE state is not foreign. When the state is foreign, KVM hyp code does not need to save any host state, and so this will not affect KVM. There appear to be further issues with unintentional SVE state discarding, largely impacting ptrace and signal handling, which will need to be addressed in separate patches. Reported-by: Eric Auger <eauger(a)redhat.com> Reported-by: Wilco Dijkstra <wilco.dijkstra(a)arm.com> Cc: stable(a)vger.kernel.org Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Florian Weimer <fweimer(a)redhat.com> Cc: Jeremy Linton <jeremy.linton(a)arm.com> Cc: Marc Zyngier <maz(a)kernel.org> Cc: Mark Brown <broonie(a)kernel.org> Cc: Oliver Upton <oliver.upton(a)linux.dev> Cc: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Will Deacon <will(a)kernel.org> Signed-off-by: Mark Rutland <mark.rutland(a)arm.com> --- arch/arm64/kernel/fpsimd.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) I believe there are some other issues in this area, but I'm sending this out on its own because I beleive the other issues are more complex while this is self-contained, and people are actively hitting this case in production. I intend to follow-up with fixes for the other cases I mention in the commit message, and for the SME case with the BUILD_BUG_ON(). Mark. diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 8c4c1a2186cc5..e4053a90ed240 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1711,8 +1711,24 @@ void fpsimd_kvm_prepare(void) */ get_cpu_fpsimd_context(); - if (test_and_clear_thread_flag(TIF_SVE)) { - sve_to_fpsimd(current); + if (!test_thread_flag(TIF_FOREIGN_FPSTATE) && + test_and_clear_thread_flag(TIF_SVE)) { + sve_user_disable(); + + /* + * The KVM hyp code doesn't set fp_type when saving the host's + * FPSIMD state. Set fp_type here in case the hyp code saves + * the host state. + * + * If hyp code does not save the host state, then the host + * state remains live on the CPU and saved fp_type is + * irrelevant until it is overwritten by a later call to + * fpsimd_save_user_state(). + * + * This is *NOT* sufficient when CONFIG_ARM64_SME=y, where + * fp_type can be FP_STATE_SVE regardless of TIF_SVE. + */ + BUILD_BUG_ON(IS_ENABLED(CONFIG_ARM64_SME)); current->thread.fp_type = FP_STATE_FPSIMD; } -- 2.30.2

2 days, 2 hours

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[PATCH RESEND] drm/komeda: Add check for komeda_get_layer_fourcc_list()

by Haoxiang Li

Add check for the return value of komeda_get_layer_fourcc_list() to catch the potential exception. Fixes: 5d51f6c0da1b ("drm/komeda: Add writeback support") Cc: stable(a)vger.kernel.org Signed-off-by: Haoxiang Li <haoxiang_li2024(a)163.com> --- drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c b/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c index ebccb74306a7..f30b3d5eeca5 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c +++ b/drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c @@ -160,6 +160,10 @@ static int komeda_wb_connector_add(struct komeda_kms_dev *kms, formats = komeda_get_layer_fourcc_list(&mdev->fmt_tbl, kwb_conn->wb_layer->layer_type, &n_formats); + if (!formats) { + kfree(kwb_conn); + return -ENOMEM; + } err = drm_writeback_connector_init(&kms->base, wb_conn, &komeda_wb_connector_funcs, -- 2.25.1

2 days, 3 hours

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[PATCH 6.1.y] net: fix data-races around sk->sk_forward_alloc

by alvalan9＠foxmail.com

From: Wang Liang <wangliang74(a)huawei.com> commit 073d89808c065ac4c672c0a613a71b27a80691cb upstream. Syzkaller reported this warning: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 16 at net/ipv4/af_inet.c:156 inet_sock_destruct+0x1c5/0x1e0 Modules linked in: CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.12.0-rc5 #26 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:inet_sock_destruct+0x1c5/0x1e0 Code: 24 12 4c 89 e2 5b 48 c7 c7 98 ec bb 82 41 5c e9 d1 18 17 ff 4c 89 e6 5b 48 c7 c7 d0 ec bb 82 41 5c e9 bf 18 17 ff 0f 0b eb 83 <0f> 0b eb 97 0f 0b eb 87 0f 0b e9 68 ff ff ff 66 66 2e 0f 1f 84 00 RSP: 0018:ffffc9000008bd90 EFLAGS: 00010206 RAX: 0000000000000300 RBX: ffff88810b172a90 RCX: 0000000000000007 RDX: 0000000000000002 RSI: 0000000000000300 RDI: ffff88810b172a00 RBP: ffff88810b172a00 R08: ffff888104273c00 R09: 0000000000100007 R10: 0000000000020000 R11: 0000000000000006 R12: ffff88810b172a00 R13: 0000000000000004 R14: 0000000000000000 R15: ffff888237c31f78 FS: 0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc63fecac8 CR3: 000000000342e000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? __warn+0x88/0x130 ? inet_sock_destruct+0x1c5/0x1e0 ? report_bug+0x18e/0x1a0 ? handle_bug+0x53/0x90 ? exc_invalid_op+0x18/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? inet_sock_destruct+0x1c5/0x1e0 __sk_destruct+0x2a/0x200 rcu_do_batch+0x1aa/0x530 ? rcu_do_batch+0x13b/0x530 rcu_core+0x159/0x2f0 handle_softirqs+0xd3/0x2b0 ? __pfx_smpboot_thread_fn+0x10/0x10 run_ksoftirqd+0x25/0x30 smpboot_thread_fn+0xdd/0x1d0 kthread+0xd3/0x100 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x34/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> ---[ end trace 0000000000000000 ]--- Its possible that two threads call tcp_v6_do_rcv()/sk_forward_alloc_add() concurrently when sk->sk_state == TCP_LISTEN with sk->sk_lock unlocked, which triggers a data-race around sk->sk_forward_alloc: tcp_v6_rcv tcp_v6_do_rcv skb_clone_and_charge_r sk_rmem_schedule __sk_mem_schedule sk_forward_alloc_add() skb_set_owner_r sk_mem_charge sk_forward_alloc_add() __kfree_skb skb_release_all skb_release_head_state sock_rfree sk_mem_uncharge sk_forward_alloc_add() sk_mem_reclaim // set local var reclaimable __sk_mem_reclaim sk_forward_alloc_add() In this syzkaller testcase, two threads call tcp_v6_do_rcv() with skb->truesize=768, the sk_forward_alloc changes like this: (cpu 1) | (cpu 2) | sk_forward_alloc ... | ... | 0 __sk_mem_schedule() | | +4096 = 4096 | __sk_mem_schedule() | +4096 = 8192 sk_mem_charge() | | -768 = 7424 | sk_mem_charge() | -768 = 6656 ... | ... | sk_mem_uncharge() | | +768 = 7424 reclaimable=7424 | | | sk_mem_uncharge() | +768 = 8192 | reclaimable=8192 | __sk_mem_reclaim() | | -4096 = 4096 | __sk_mem_reclaim() | -8192 = -4096 != 0 The skb_clone_and_charge_r() should not be called in tcp_v6_do_rcv() when sk->sk_state is TCP_LISTEN, it happens later in tcp_v6_syn_recv_sock(). Fix the same issue in dccp_v6_do_rcv(). Suggested-by: Eric Dumazet <edumazet(a)google.com> Reviewed-by: Eric Dumazet <edumazet(a)google.com> Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets") Signed-off-by: Wang Liang <wangliang74(a)huawei.com> Link: https://patch.msgid.link/20241107023405.889239-1-wangliang74@huawei.com Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> Signed-off-by: Alva Lan <alvalan9(a)foxmail.com> --- Backport to fix CVE-2024-53124. Link: https://nvd.nist.gov/vuln/detail/CVE-2024-53124 --- net/dccp/ipv6.c | 2 +- net/ipv6/tcp_ipv6.c | 4 +--- 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index d90bb941f2ad..8f5f56b1e5f8 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -615,7 +615,7 @@ static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) by tcp. Feel free to propose better solution. --ANK (980728) */ - if (np->rxopt.all) + if (np->rxopt.all && sk->sk_state != DCCP_LISTEN) opt_skb = skb_clone_and_charge_r(skb, sk); if (sk->sk_state == DCCP_OPEN) { /* Fast path */ diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 06b4acbfd314..0ccaa78f6ff3 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1463,7 +1463,7 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) by tcp. Feel free to propose better solution. --ANK (980728) */ - if (np->rxopt.all) + if (np->rxopt.all && sk->sk_state != TCP_LISTEN) opt_skb = skb_clone_and_charge_r(skb, sk); reason = SKB_DROP_REASON_NOT_SPECIFIED; @@ -1502,8 +1502,6 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) if (nsk != sk) { if (tcp_child_process(sk, nsk, skb)) goto reset; - if (opt_skb) - __kfree_skb(opt_skb); return 0; } } else -- 2.43.0

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