- Linux-kselftest-mirror - lists.linaro.org

[PATCH v2 5/7] rseq: selftests: Add non-glibc compatibility fixes

by Aqib Faruqui

The rseq selftests rely on features provided by glibc that may not be available in non-glibc C libraries: 1. The __GNU_PREREQ macro and glibc's thread pointer implementation are not available in non-glibc libraries 2. The __NR_rseq syscall number may not be defined in non-glibc headers Add a fallback thread pointer implementation for non-glibc systems using the pre-existing inline assembly to access thread-local storage directly via %fs/%gs registers. Also provide a fallback definition for __NR_rseq when not already defined by the C library headers: 527 for alpha and 293 for other architectures. Signed-off-by: Aqib Faruqui <aqibaf(a)amazon.com> --- .../selftests/rseq/rseq-x86-thread-pointer.h | 14 ++++++++++++++ tools/testing/selftests/rseq/rseq.c | 8 ++++++++ 2 files changed, 22 insertions(+) diff --git a/tools/testing/selftests/rseq/rseq-x86-thread-pointer.h b/tools/testing/selftests/rseq/rseq-x86-thread-pointer.h index d3133587d..a7c402926 100644 --- a/tools/testing/selftests/rseq/rseq-x86-thread-pointer.h +++ b/tools/testing/selftests/rseq/rseq-x86-thread-pointer.h @@ -14,6 +14,7 @@ extern "C" { #endif +#ifdef __GLIBC__ #if __GNUC_PREREQ (11, 1) static inline void *rseq_thread_pointer(void) { @@ -32,6 +33,19 @@ static inline void *rseq_thread_pointer(void) return __result; } #endif /* !GCC 11 */ +#else +static inline void *rseq_thread_pointer(void) +{ + void *__result; + +# ifdef __x86_64__ + __asm__ ("mov %%fs:0, %0" : "=r" (__result)); +# else + __asm__ ("mov %%gs:0, %0" : "=r" (__result)); +# endif + return __result; +} +#endif /* !__GLIBC__ */ #ifdef __cplusplus } diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c index 663a9cef1..1a6f73c98 100644 --- a/tools/testing/selftests/rseq/rseq.c +++ b/tools/testing/selftests/rseq/rseq.c @@ -36,6 +36,14 @@ #include "../kselftest.h" #include "rseq.h" +#ifndef __NR_rseq +#ifdef __alpha__ +#define __NR_rseq 527 +#else +#define __NR_rseq 293 +#endif +#endif + /* * Define weak versions to play nice with binaries that are statically linked * against a libc that doesn't support registering its own rseq. -- 2.47.3

1 day, 2 hours

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[PATCH v2 4/7] KVM: selftests: Add backtrace fallback

by Aqib Faruqui

The backtrace() function is a GNU extension available in glibc but may not be present in non-glibc libraries. KVM selftests use backtrace() for error reporting and debugging. Add conditional inclusion of execinfo.h only for glibc builds and provide a weak stub implementation of backtrace() that returns 0 (stack trace empty) for non-glibc systems. Signed-off-by: Aqib Faruqui <aqibaf(a)amazon.com> --- tools/testing/selftests/kvm/lib/assert.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/lib/assert.c b/tools/testing/selftests/kvm/lib/assert.c index b49690658..c9778dc6c 100644 --- a/tools/testing/selftests/kvm/lib/assert.c +++ b/tools/testing/selftests/kvm/lib/assert.c @@ -6,11 +6,19 @@ */ #include "test_util.h" -#include <execinfo.h> #include <sys/syscall.h> +#ifdef __GLIBC__ +#include <execinfo.h> /* backtrace */ +#endif + #include "kselftest.h" +int __attribute__((weak)) backtrace(void **buffer, int size) +{ + return 0; +} + /* Dumps the current stack trace to stderr. */ static void __attribute__((noinline)) test_dump_stack(void); static void test_dump_stack(void) -- 2.47.3

1 day, 2 hours

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[PATCH v2 3/7] selftests: kselftest: Add memfd_create syscall compatibility

by Aqib Faruqui

The memfd_create function and related MFD_* flags may not be available in non-glibc C libraries. Some selftests use memfd_create for memory backing operations. Add fallback definitions for MFD_CLOEXEC and MFD_HUGETLB flags, and provide a memfd_create wrapper. Signed-off-by: Aqib Faruqui <aqibaf(a)amazon.com> --- tools/testing/selftests/kselftest.h | 19 +++++++++++++++++++ tools/testing/selftests/kvm/lib/kvm_util.c | 1 + 2 files changed, 20 insertions(+) diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h index c3b6d2604..f362c6766 100644 --- a/tools/testing/selftests/kselftest.h +++ b/tools/testing/selftests/kselftest.h @@ -57,6 +57,7 @@ #include <string.h> #include <stdio.h> #include <sys/utsname.h> +#include <sys/syscall.h> #endif #ifndef ARRAY_SIZE @@ -80,6 +81,24 @@ #endif #endif /* end arch */ +#ifndef MFD_CLOEXEC +#define MFD_CLOEXEC 0x0001U +#endif + +#ifndef MFD_HUGETLB +#define MFD_HUGETLB 0x0004U +#endif + +static inline int memfd_create(const char *name, unsigned int flags) +{ +#ifdef __NR_memfd_create + return syscall(__NR_memfd_create, name, flags); +#else + errno = ENOSYS; + return -1; +#endif +} + /* define kselftest exit codes */ #define KSFT_PASS 0 #define KSFT_FAIL 1 diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index c3f5142b0..a78b64117 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -15,6 +15,7 @@ #include <sys/resource.h> #include <sys/types.h> #include <sys/stat.h> +#include <sys/syscall.h> #include <unistd.h> #include <linux/kernel.h> -- 2.47.3

1 day, 2 hours

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[PATCH v2 2/7] selftests: harness: Include pidfd.h to get syscall definitions from tools/

by Aqib Faruqui

The kselftest harness uses pidfd_open() for test timeout handling but may not have access to the syscall definitions in non-glibc environments. Include pidfd.h to ensure the syscall numbers are available. Signed-off-by: Aqib Faruqui <aqibaf(a)amazon.com> --- tools/testing/selftests/kselftest_harness.h | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h index 2925e47db..1dd3e5a1b 100644 --- a/tools/testing/selftests/kselftest_harness.h +++ b/tools/testing/selftests/kselftest_harness.h @@ -69,6 +69,7 @@ #include <unistd.h> #include "kselftest.h" +#include "pidfd/pidfd.h" #define TEST_TIMEOUT_DEFAULT 30 -- 2.47.3

1 day, 2 hours

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[PATCH v2 1/7] selftests/pidfd: Add architecture-specific fallback definitions for pidfd_open

by Aqib Faruqui

The pidfd_open syscall number varies by architecture. Add fallback definitions for Alpha (544) and other architectures (434) to ensure compatibility with non-glibc C libraries that may not define these syscall numbers. Signed-off-by: Aqib Faruqui <aqibaf(a)amazon.com> --- tools/testing/selftests/pidfd/pidfd.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h index f87993def..c373ff18e 100644 --- a/tools/testing/selftests/pidfd/pidfd.h +++ b/tools/testing/selftests/pidfd/pidfd.h @@ -45,8 +45,12 @@ #endif #ifndef __NR_pidfd_open +#ifdef __alpha__ +#define __NR_pidfd_open 544 +#else #define __NR_pidfd_open 434 #endif +#endif #ifndef __NR_pidfd_send_signal #define __NR_pidfd_send_signal 424 -- 2.47.3

1 day, 2 hours

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[PATCH net-next] selftest: netcons: create a torture test

by Breno Leitao

Create a netconsole test that puts a lot of pressure on the netconsole list manipulation. Do it by creating dynamic targets and deleting targets while messages are being sent. Also put interface down while the messages are being sent, as creating parallel targets. The code launches three background jobs on distinct schedules: * Toggle netcons target every 30 iterations * create and delete random_target every 50 iterations * toggle iface every 70 iterations This creates multiple concurrency sources that interact with netconsole states. This is good practice to simulate stress, and exercise netpoll and netconsole locks. This test already found an issue as reported in [1] Link: https://lore.kernel.org/all/20250901-netpoll_memleak-v1-1-34a181977dfc@debi… [1] Signed-off-by: Breno Leitao <leitao(a)debian.org> --- tools/testing/selftests/drivers/net/Makefile | 1 + .../selftests/drivers/net/netcons_torture.sh | 133 +++++++++++++++++++++ 2 files changed, 134 insertions(+) diff --git a/tools/testing/selftests/drivers/net/Makefile b/tools/testing/selftests/drivers/net/Makefile index 984ece05f7f92..2b253b1ff4f38 100644 --- a/tools/testing/selftests/drivers/net/Makefile +++ b/tools/testing/selftests/drivers/net/Makefile @@ -17,6 +17,7 @@ TEST_PROGS := \ netcons_fragmented_msg.sh \ netcons_overflow.sh \ netcons_sysdata.sh \ + netcons_torture.sh \ netpoll_basic.py \ ping.py \ queues.py \ diff --git a/tools/testing/selftests/drivers/net/netcons_torture.sh b/tools/testing/selftests/drivers/net/netcons_torture.sh new file mode 100755 index 0000000000000..d41884c83cab3 --- /dev/null +++ b/tools/testing/selftests/drivers/net/netcons_torture.sh @@ -0,0 +1,133 @@ +#!/usr/bin/env bash +# SPDX-License-Identifier: GPL-2.0 + +# Repeatedly send kernel messages, toggles netconsole targets on and off, +# creates and deletes targets in parallel, and toggles the source interface to +# simulate stress conditions. +# +# This test aims verify the robustness of netconsole under dynamic +# configurations and concurrent operations. +# +# The major goal is to run this test with LOCKDEP, Kmemleak and KASAN to make +# sure no issues is reported. +# +# Author: Breno Leitao <leitao(a)debian.org> + +set -euo pipefail + +SCRIPTDIR=$(dirname "$(readlink -e "${BASH_SOURCE[0]}")") + +source "${SCRIPTDIR}"/lib/sh/lib_netcons.sh + +# Number of times the main loop run +ITERATIONS=${1:-1000} + +# Only test extended format +FORMAT="extended" +# And ipv6 only +IP_VERSION="ipv6" + +# Create, enable and delete some targets. +create_and_delete_random_target() { + COUNT=1 + RND_PREFIX=$(mktemp -u netcons_rnd_XXXX_) + + if [ -d "${NETCONS_CONFIGFS}/${RND_PREFIX}${COUNT}" ] || \ + [ -d "${NETCONS_CONFIGFS}/${RND_PREFIX}0" ]; then + echo "Function didn't finish yet, skipping it." >&2 + return + fi + + # enable COUNT targets + for i in $(seq 0 ${COUNT}) + do + RND_TARGET="${RND_PREFIX}"${i} + RND_TARGET_PATH="${NETCONS_CONFIGFS}"/"${RND_TARGET}" + + # Basic population so the target can come up + mkdir "${RND_TARGET_PATH}" + echo "${DSTIP}" > "${RND_TARGET_PATH}"/remote_ip + echo "${SRCIP}" > "${RND_TARGET_PATH}"/local_ip + echo "${DSTMAC}" > "${RND_TARGET_PATH}"/remote_mac + echo "${SRCIF}" > "${RND_TARGET_PATH}"/dev_name + + echo 1 > "${RND_TARGET_PATH}"/enabled + done + + echo "netconsole selftest: ${COUNT} additional target was created" > /dev/kmsg + # disable them all + for i in $(seq 0 ${COUNT}) + do + RND_TARGET="${RND_PREFIX}"${i} + RND_TARGET_PATH="${NETCONS_CONFIGFS}"/"${RND_TARGET}" + echo 0 > "${RND_TARGET_PATH}"/enabled + rmdir "${RND_TARGET_PATH}" + done +} + +# Disable and enable the target mid-air, while messages +# are being transmitted. +toggle_netcons_target() { + for i in $(seq 2) + do + if [ ! -d "${NETCONS_PATH}" ] + then + break + fi + echo 0 > "${NETCONS_PATH}"/enabled 2> /dev/null || true + # Try to enable a bit harder, given it might fail to enable + # Write to `enabled` might fail depending on the lock, which is + # highly contentious here + for _ in $(seq 5) + do + echo 1 > "${NETCONS_PATH}"/enabled 2> /dev/null || true + done + done +} + +toggle_iface(){ + ip link set "${SRCIF}" down + ip link set "${SRCIF}" up +} + +# Start here + +modprobe netdevsim 2> /dev/null || true +modprobe netconsole 2> /dev/null || true + +# Check for basic system dependency and exit if not found +check_for_dependencies +# Set current loglevel to KERN_INFO(6), and default to KERN_NOTICE(5) +echo "6 5" > /proc/sys/kernel/printk +# Remove the namespace, interfaces and netconsole target on exit +trap cleanup EXIT +# Create one namespace and two interfaces +set_network "${IP_VERSION}" +# Create a dynamic target for netconsole +create_dynamic_target "${FORMAT}" + +for i in $(seq "$ITERATIONS") +do + for _ in $(seq 10) + do + echo "${MSG}: ${TARGET} ${i}" > /dev/kmsg + wait + done + + if (( i % 30 == 0 )); then + toggle_netcons_target & + fi + + if (( i % 50 == 0 )); then + # create some targets, enable them, send msg and disable + # all in a parallel thread + create_and_delete_random_target & + fi + + if (( i % 70 == 0 )); then + toggle_iface & + fi +done +wait + +exit "${ksft_pass}" --- base-commit: 2fd4161d0d2547650d9559d57fc67b4e0a26a9e3 change-id: 20250902-netconsole_torture-8fc23f0aca99 Best regards, -- Breno Leitao <leitao(a)debian.org>

1 day, 3 hours

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[PATCH net-next 0/5] net: common feature compute for upper interface

by Hangbin Liu

Some high-level virtual drivers need to compute features from their lower devices, but each currently has its own implementation and may miss some feature computations. This patch set introduces a common function to compute features for such devices. Currently, bonding, team, and bridge have been updated to use the new helper. Hangbin Liu (5): net: add a common function to compute features from lowers devices bonding: use common function to compute the features team: use common function to compute the features net: bridge: use common function to compute the features selftests/net: add offload checking test for virtual interface drivers/net/bonding/bond_main.c | 99 +---------- drivers/net/team/team_core.c | 73 +------- include/linux/netdevice.h | 19 +++ net/bridge/br_if.c | 22 +-- net/core/dev.c | 79 +++++++++ tools/testing/selftests/net/config | 2 + tools/testing/selftests/net/vdev_offload.sh | 174 ++++++++++++++++++++ 7 files changed, 285 insertions(+), 183 deletions(-) create mode 100755 tools/testing/selftests/net/vdev_offload.sh -- 2.50.1

1 day, 3 hours

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[Patch v2] selftests/mm: check content to see whether mremap corrupt data

by Wei Yang

After mremap(), add a check on content to see whether mremap corrupt data. Signed-off-by: Wei Yang <richard.weiyang(a)gmail.com> --- v2: add check on content instead of just test backed folio --- tools/testing/selftests/mm/split_huge_page_test.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index 10ae65ea032f..229b6dcabece 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -423,10 +423,14 @@ static void split_pte_mapped_thp(void) /* smap does not show THPs after mremap, use kpageflags instead */ thp_size = 0; - for (i = 0; i < pagesize * 4; i++) + for (i = 0; i < pagesize * 4; i++) { + if (pte_mapped[i] != (char)i) + ksft_exit_fail_msg("%ld byte corrupted\n", i); + if (i % pagesize == 0 && is_backed_by_folio(&pte_mapped[i], pmd_order, pagemap_fd, kpageflags_fd)) thp_size++; + } if (thp_size != 4) ksft_exit_fail_msg("Some THPs are missing during mremap\n"); -- 2.34.1

1 day, 3 hours

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[bpf-next v2 0/5] powerpc64/bpf: Add support for bpf arena and arena atomics

by Saket Kumar Bhaskar

This patch series introduces support for the PROBE_MEM32, bpf_addr_space_cast and PROBE_ATOMIC instructions in the powerpc BPF JIT, facilitating the implementation of BPF arena and arena atomics. The last patch in the series has fix for arena spinlock selftest failure. All selftests related to bpf_arena, bpf_arena_atomic(except load_acquire/store_release) enablement are passing: # ./test_progs -t arena_list #5/1 arena_list/arena_list_1:OK #5/2 arena_list/arena_list_1000:OK #5 arena_list:OK Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED # ./test_progs -t arena_htab #4/1 arena_htab/arena_htab_llvm:OK #4/2 arena_htab/arena_htab_asm:OK #4 arena_htab:OK Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED # ./test_progs -t verifier_arena #464/1 verifier_arena/basic_alloc1:OK #464/2 verifier_arena/basic_alloc2:OK #464/3 verifier_arena/basic_alloc3:OK #464/4 verifier_arena/iter_maps1:OK #464/5 verifier_arena/iter_maps2:OK #464/6 verifier_arena/iter_maps3:OK #464 verifier_arena:OK #465/1 verifier_arena_large/big_alloc1:OK #465/2 verifier_arena_large/big_alloc2:OK #465 verifier_arena_large:OK Summary: 2/8 PASSED, 0 SKIPPED, 0 FAILED # ./test_progs -t arena_atomics #3/1 arena_atomics/add:OK #3/2 arena_atomics/sub:OK #3/3 arena_atomics/and:OK #3/4 arena_atomics/or:OK #3/5 arena_atomics/xor:OK #3/6 arena_atomics/cmpxchg:OK #3/7 arena_atomics/xchg:OK #3/8 arena_atomics/uaf:OK #3/9 arena_atomics/load_acquire:SKIP #3/10 arena_atomics/store_release:SKIP #3 arena_atomics:OK (SKIP: 2/10) Summary: 1/8 PASSED, 2 SKIPPED, 0 FAILED All selftests related to arena_spin_lock are passing: # ./test_progs -t arena_spin_lock #6/1 arena_spin_lock/arena_spin_lock_1:OK #6/2 arena_spin_lock/arena_spin_lock_1000:OK #6/3 arena_spin_lock/arena_spin_lock_50000:OK #6 arena_spin_lock:OK Summary: 1/3 PASSED, 0 SKIPPED, 0 FAILED Changes since v1: Addressed comments from Chris: * Squashed introduction of bpf_jit_emit_probe_mem_store() and its usage in one patch. * Defined and used PPC_RAW_RLDICL_DOT to avoid the CMPDI. * Removed conditional statement for fixup[0] = PPC_RAW_LI(dst_reg, 0); * Indicated this change is limited to powerpc64 in subject. Addressed comments from Alexei: * Removed skel->rodata->nr_cpus = get_nprocs() and its usage to get currently online cpus(as it needs to be updated from userspace). Saket Kumar Bhaskar (5): powerpc64/bpf: Implement PROBE_MEM32 pseudo instructions powerpc64/bpf: Implement bpf_addr_space_cast instruction powerpc64/bpf: Introduce bpf_jit_emit_atomic_ops() to emit atomic instructions powerpc64/bpf: Implement PROBE_ATOMIC instructions selftests/bpf: Fix arena_spin_lock selftest failure arch/powerpc/include/asm/ppc-opcode.h | 1 + arch/powerpc/net/bpf_jit.h | 6 +- arch/powerpc/net/bpf_jit_comp.c | 32 +- arch/powerpc/net/bpf_jit_comp32.c | 2 +- arch/powerpc/net/bpf_jit_comp64.c | 401 +++++++++++++----- .../bpf/prog_tests/arena_spin_lock.c | 13 + .../selftests/bpf/progs/arena_spin_lock.c | 5 +- 7 files changed, 347 insertions(+), 113 deletions(-) -- 2.43.5

1 day, 4 hours

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[PATCH net-next v5] selftests: net: add test for ipv6 fragmentation

by Brett A C Sheffield

Add selftest for the IPv6 fragmentation regression which affected several stable kernels. Commit a18dfa9925b9 ("ipv6: save dontfrag in cork") was backported to stable without some prerequisite commits. This caused a regression when sending IPv6 UDP packets by preventing fragmentation and instead returning -1 (EMSGSIZE). Add selftest to check for this issue by attempting to send a packet larger than the interface MTU. The packet will be fragmented on a working kernel, with sendmsg(2) correctly returning the expected number of bytes sent. When the regression is present, sendmsg returns -1 and sets errno to EMSGSIZE. Link: https://lore.kernel.org/stable/aElivdUXqd1OqgMY@karahi.gladserv.com Signed-off-by: Brett A C Sheffield <bacs(a)librecast.net> Reviewed-by: Willem de Bruijn <willemb(a)google.com> --- Thanks for the reviews Willem and Jakub. On 2025-09-01 09:45, Willem de Bruijn wrote: > > +int main(void) > > +{ > > + struct in6_addr addr = { > > + .s6_addr[15] = 0x01, /* ::1 */ > > + }; > > + struct sockaddr_in6 sa = { > > + .sin6_family = AF_INET6, > > + .sin6_addr = addr, > > + .sin6_port = 9 /* port 9/udp (DISCARD) */ > > htons addr is already initialized in network byte order (BE) here. Verified with: char ip6[INET6_ADDRSTRLEN]; inet_ntop(AF_INET6, &(sa.sin6_addr), ip6, INET6_ADDRSTRLEN); printf("The address is %s\n", ip6); which prints "The address is ::1" All other suggestions adopted in v5. v5 changes: - disable_dad: delete - not needed for lo - main: simplify failure paths - main: char -> static char buf - setup: remove pointless return value - setup: remove unused variable fd - setup: merge with interface_up() to simplify - setup: check all system call return values - remove no longer used headers v4 changes: - fix "else should follow close brace" (checkpatch ERROR) v3 changes: - add usleep instead of busy polling on sendmsg - simplify error handling by using error() and leaving cleanup to O/S - use loopback interface - don't bother creating TAP - send to localhost (::1) v2 changes: - remove superfluous namespace calls - unshare(2) suffices - remove usleep(). Don't wait for the interface to be ready, just send, and handle the (less likely) error case by retrying. - set destination address only once - document our use of the IPv6 link-local source address - send to port 9 (DISCARD) instead of 4242 (DONT PANIC) - ensure sockets are closed on failure paths - use KSFT exit codes for clarity v4: https://lore.kernel.org/netdev/20250901123757.13112-1-bacs@librecast.net v3: https://lore.kernel.org/netdev/20250901112248.5218-1-bacs@librecast.net v2: https://lore.kernel.org/netdev/20250831102908.14655-1-bacs@librecast.net v1: https://lore.kernel.org/netdev/20250825092548.4436-3-bacs@librecast.net tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/Makefile | 1 + .../selftests/net/ipv6_fragmentation.c | 115 ++++++++++++++++++ 3 files changed, 117 insertions(+) create mode 100644 tools/testing/selftests/net/ipv6_fragmentation.c diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore index 47c293c2962f..3d4b4a53dfda 100644 --- a/tools/testing/selftests/net/.gitignore +++ b/tools/testing/selftests/net/.gitignore @@ -16,6 +16,7 @@ ip_local_port_range ipsec ipv6_flowlabel ipv6_flowlabel_mgr +ipv6_fragmentation log.txt msg_oob msg_zerocopy diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index eef0b8f8a7b0..276e0481d996 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -117,6 +117,7 @@ TEST_GEN_FILES += tfo TEST_PROGS += tfo_passive.sh TEST_PROGS += broadcast_pmtu.sh TEST_PROGS += ipv6_force_forwarding.sh +TEST_GEN_PROGS += ipv6_fragmentation TEST_PROGS += route_hint.sh # YNL files, must be before "include ..lib.mk" diff --git a/tools/testing/selftests/net/ipv6_fragmentation.c b/tools/testing/selftests/net/ipv6_fragmentation.c new file mode 100644 index 000000000000..b76ce7b713fc --- /dev/null +++ b/tools/testing/selftests/net/ipv6_fragmentation.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Author: Brett A C Sheffield <bacs(a)librecast.net> + * + * Kernel selftest for the IPv6 fragmentation regression which affected stable + * kernels: + * + * https://lore.kernel.org/stable/aElivdUXqd1OqgMY@karahi.gladserv.com + * + * Commit: a18dfa9925b9 ("ipv6: save dontfrag in cork") was backported to stable + * without some prerequisite commits. + * + * This caused a regression when sending IPv6 UDP packets by preventing + * fragmentation and instead returning -1 (EMSGSIZE). + * + * This selftest demonstrates the issue by sending an IPv6 UDP packet to + * localhost (::1) on the loopback interface from the autoconfigured link-local + * address. + * + * sendmsg(2) returns bytes sent correctly on a working kernel, and returns -1 + * (EMSGSIZE) when the regression is present. + * + * The regression was not present in the mainline kernel, but add this test to + * catch similar breakage in future. + */ + +#define _GNU_SOURCE + +#include <error.h> +#include <net/if.h> +#include <netinet/in.h> +#include <sched.h> +#include <stdio.h> +#include <sys/ioctl.h> +#include <sys/socket.h> +#include <unistd.h> +#include "../kselftest.h" + +#define MTU 1500 +#define LARGER_THAN_MTU 8192 + +static void setup(void) +{ + struct ifreq ifr = { + .ifr_name = "lo" + }; + int ctl; + + /* we need to set MTU, so do this in a namespace to play nicely */ + if (unshare(CLONE_NEWNET) == -1) + error(KSFT_FAIL, errno, "unshare"); + + ctl = socket(AF_LOCAL, SOCK_STREAM, 0); + if (ctl == -1) + error(KSFT_FAIL, errno, "socket"); + + /* ensure MTU is smaller than what we plan to send */ + ifr.ifr_mtu = MTU; + if (ioctl(ctl, SIOCSIFMTU, &ifr) == -1) + error(KSFT_FAIL, errno, "ioctl: set MTU"); + + /* bring up interface */ + if (ioctl(ctl, SIOCGIFFLAGS, &ifr) == -1) + error(KSFT_FAIL, errno, "ioctl SIOCGIFFLAGS"); + ifr.ifr_flags = ifr.ifr_flags | IFF_UP; + if (ioctl(ctl, SIOCSIFFLAGS, &ifr) == -1) + error(KSFT_FAIL, errno, "ioctl: bring interface up"); + + if (close(ctl) == -1) + error(KSFT_FAIL, errno, "close"); +} + +int main(void) +{ + struct in6_addr addr = { + .s6_addr[15] = 0x01, /* ::1 */ + }; + struct sockaddr_in6 sa = { + .sin6_family = AF_INET6, + .sin6_addr = addr, + .sin6_port = 9 /* port 9/udp (DISCARD) */ + }; + static char buf[LARGER_THAN_MTU] = {0}; + struct iovec iov = { .iov_base = buf, .iov_len = sizeof(buf) }; + struct msghdr msg = { + .msg_iov = &iov, + .msg_iovlen = 1, + .msg_name = (struct sockaddr *)&sa, + .msg_namelen = sizeof(sa), + }; + ssize_t rc; + int err = KSFT_FAIL; + int s; + + printf("Testing IPv6 fragmentation\n"); + setup(); + s = socket(AF_INET6, SOCK_DGRAM, 0); +send_again: + rc = sendmsg(s, &msg, 0); + if (rc == -1) { + /* if interface wasn't ready, try again */ + if (errno == EADDRNOTAVAIL) { + usleep(1000); + goto send_again; + } + error(KSFT_FAIL, errno, "sendmsg"); + } else if (rc != LARGER_THAN_MTU) { + error(KSFT_FAIL, errno, "sendmsg returned %zi, expected %i", + rc, LARGER_THAN_MTU); + } + printf("[PASS] sendmsg() returned %zi\n", rc); + err = KSFT_PASS; + close(s); + return err; +} base-commit: cd8a4cfa6bb43a441901e82f5c222dddc75a18a3 -- 2.49.1

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