Linux-kselftest-mirror May 2025

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213 discussions

[RFC net-next v1 1/2] udp: Introduce UDP_STOP_RCV option for UDP

by Jiayuan Chen

For some services we are using "established-over-unconnected" model. ''' // create unconnected socket and 'listen()' srv_fd = socket(AF_INET, SOCK_DGRAM) setsockopt(srv_fd, SO_REUSEPORT) bind(srv_fd, SERVER_ADDR, SERVER_PORT) // 'accept()' data, client_addr = recvmsg(srv_fd) // create a connected socket for this request cli_fd = socket(AF_INET, SOCK_DGRAM) setsockopt(cli_fd, SO_REUSEPORT) bind(cli_fd, SERVER_ADDR, SERVER_PORT) connect(cli, client_addr) ... // do handshake with cli_fd ''' This programming pattern simulates accept() using UDP, creating a new socket for each client request. The server can then use separate sockets to handle client requests, avoiding the need to use a single UDP socket for I/O transmission. But there is a race condition between the bind() and connect() of the connected socket: We might receive unexpected packets belonging to the unconnected socket before connect() is executed, which is not what we need. (Of course, before connect(), the unconnected socket will also receive packets from the connected socket, which is easily resolved because upper-layer protocols typically require explicit boundaries, and we receive a complete packet before creating a connected socket.) Before this patch, the connected socket had to filter requests at recvmsg time, acting as a dispatcher to some extent. With this patch, we can consider the bind and connect operations to be atomic. Signed-off-by: Jiayuan Chen <jiayuan.chen(a)linux.dev> --- include/linux/udp.h | 1 + include/uapi/linux/udp.h | 1 + net/ipv4/udp.c | 13 ++++++++++--- net/ipv6/udp.c | 5 +++-- 4 files changed, 15 insertions(+), 5 deletions(-) diff --git a/include/linux/udp.h b/include/linux/udp.h index 895240177f4f..8d281a0c0d9d 100644 --- a/include/linux/udp.h +++ b/include/linux/udp.h @@ -42,6 +42,7 @@ enum { UDP_FLAGS_ENCAP_ENABLED, /* This socket enabled encap */ UDP_FLAGS_UDPLITE_SEND_CC, /* set via udplite setsockopt */ UDP_FLAGS_UDPLITE_RECV_CC, /* set via udplite setsockopt */ + UDP_FLAGS_STOP_RCV, /* Stop receiving packets */ }; struct udp_sock { diff --git a/include/uapi/linux/udp.h b/include/uapi/linux/udp.h index edca3e430305..bb8e0a749a55 100644 --- a/include/uapi/linux/udp.h +++ b/include/uapi/linux/udp.h @@ -34,6 +34,7 @@ struct udphdr { #define UDP_NO_CHECK6_RX 102 /* Disable accepting checksum for UDP6 */ #define UDP_SEGMENT 103 /* Set GSO segmentation size */ #define UDP_GRO 104 /* This socket can receive UDP GRO packets */ +#define UDP_STOP_RCV 105 /* This socket will not receive any packets */ /* UDP encapsulation types */ #define UDP_ENCAP_ESPINUDP_NON_IKE 1 /* unused draft-ietf-ipsec-nat-t-ike-00/01 */ diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index f9f5b92cf4b6..764d337ab1b3 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -376,7 +376,8 @@ static int compute_score(struct sock *sk, const struct net *net, if (!net_eq(sock_net(sk), net) || udp_sk(sk)->udp_port_hash != hnum || - ipv6_only_sock(sk)) + ipv6_only_sock(sk) || + udp_test_bit(STOP_RCV, sk)) return -1; if (sk->sk_rcv_saddr != daddr) @@ -494,7 +495,7 @@ static struct sock *udp4_lib_lookup2(const struct net *net, result = inet_lookup_reuseport(net, sk, skb, sizeof(struct udphdr), saddr, sport, daddr, hnum, udp_ehashfn); - if (!result) { + if (!result || udp_test_bit(STOP_RCV, result)) { result = sk; continue; } @@ -3031,7 +3032,9 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, set_xfrm_gro_udp_encap_rcv(up->encap_type, sk->sk_family, sk); sockopt_release_sock(sk); break; - + case UDP_STOP_RCV: + udp_assign_bit(STOP_RCV, sk, valbool); + break; /* * UDP-Lite's partial checksum coverage (RFC 3828). */ @@ -3120,6 +3123,10 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname, val = udp_test_bit(GRO_ENABLED, sk); break; + case UDP_STOP_RCV: + val = udp_test_bit(STOP_RCV, sk); + break; + /* The following two cannot be changed on UDP sockets, the return is * always 0 (which corresponds to the full checksum coverage of UDP). */ case UDPLITE_SEND_CSCOV: diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 7317f8e053f1..55896a78e94b 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -137,7 +137,8 @@ static int compute_score(struct sock *sk, const struct net *net, if (!net_eq(sock_net(sk), net) || udp_sk(sk)->udp_port_hash != hnum || - sk->sk_family != PF_INET6) + sk->sk_family != PF_INET6 || + udp_test_bit(STOP_RCV, sk)) return -1; if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr)) @@ -245,7 +246,7 @@ static struct sock *udp6_lib_lookup2(const struct net *net, result = inet6_lookup_reuseport(net, sk, skb, sizeof(struct udphdr), saddr, sport, daddr, hnum, udp6_ehashfn); - if (!result) { + if (!result || udp_test_bit(STOP_RCV, result)) { result = sk; continue; } -- 2.47.1

2 weeks, 6 days

[PATCH v3 0/3] RISC-V KVM selftests improvements

by Atish Patra

This series improves the following tests. 1. Get-reg-list : Adds vector support 2. SBI PMU test : Distinguish between different types of illegal exception The first patch is just helper patch that adds stval support during exception handling. Signed-off-by: Atish Patra <atishp(a)rivosinc.com> --- Changes in v3: - Dropped the redundant macros and rv32 specific csr details. - Changed to vcpu_get_reg from __vcpu_get_reg based on suggestion from Drew. - Added RB tags from Drew. - Link to v2: https://lore.kernel.org/r/20250429-kvm_selftest_improve-v2-0-51713f91e04a@r… Changes in v2: - Rebased on top of Linux 6.15-rc4 - Changed from ex_regs to pt_regs based on Drew's suggestion. - Dropped Anup's review on PATCH1 as it is significantly changed from last review. - Moved the instruction decoding macros to a common header file. - Improved the vector reg list test as per the feedback. - Link to v1: https://lore.kernel.org/r/20250324-kvm_selftest_improve-v1-0-583620219d4f@r… --- Atish Patra (3): KVM: riscv: selftests: Align the trap information wiht pt_regs KVM: riscv: selftests: Decode stval to identify exact exception type KVM: riscv: selftests: Add vector extension tests .../selftests/kvm/include/riscv/processor.h | 23 +++- tools/testing/selftests/kvm/lib/riscv/handlers.S | 139 +++++++++++---------- tools/testing/selftests/kvm/lib/riscv/processor.c | 2 +- tools/testing/selftests/kvm/riscv/arch_timer.c | 2 +- tools/testing/selftests/kvm/riscv/ebreak_test.c | 2 +- tools/testing/selftests/kvm/riscv/get-reg-list.c | 132 +++++++++++++++++++ tools/testing/selftests/kvm/riscv/sbi_pmu_test.c | 24 +++- 7 files changed, 247 insertions(+), 77 deletions(-) --- base-commit: f15d97df5afae16f40ecef942031235d1c6ba14f change-id: 20250324-kvm_selftest_improve-9bedb9f0a6d3 -- Regards, Atish patra

2 weeks, 6 days

[PATCH 0/2] Update kunit doc and tool with tips to build errors

by Shuah Khan

kunit kernel build could fail if there are ny build artifacts from a prior kernel build. These can be hard to debug if the build artifact happens to be generated header file. It took me a while to debug kunit build fail on ARCH=x86_64 in a tree which had a generated header file arch/x86/realmode/rm/pasyms.h make ARCH=um mrproper will not clean the tree. It is necessary to run make ARCH=x86_64 mrproper Example work-flow that could lead to this: make allmodconfig (x86_64) make ./tools/testing/kunit/kunit.py run Add this to the documentation and kunit.py build help message. Shuah Khan (2): doc: kunit: add information about cleaning source trees kunit: add tips to clean source tree to build help message Documentation/dev-tools/kunit/start.rst | 12 ++++++++++++ tools/testing/kunit/kunit.py | 2 +- 2 files changed, 13 insertions(+), 1 deletion(-) -- 2.47.2

3 weeks

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Linux-kselftest-mirror May 2025