September 2025 - Linux-kselftest-mirror

[PATCH v3 1/2] libbpf: add support for printing BTF character arrays as strings

by Blake Jones

The BTF dumper code currently displays arrays of characters as just that - arrays, with each character formatted individually. Sometimes this is what makes sense, but it's nice to be able to treat that array as a string. This change adds a special case to the btf_dump functionality to allow 0-terminated arrays of single-byte integer values to be printed as character strings. Characters for which isprint() returns false are printed as hex-escaped values. This is enabled when the new ".emit_strings" is set to 1 in the btf_dump_type_data_opts structure. As an example, here's what it looks like to dump the string "hello" using a few different field values for btf_dump_type_data_opts (.compact = 1): - .emit_strings = 0, .skip_names = 0: (char[6])['h','e','l','l','o',] - .emit_strings = 0, .skip_names = 1: ['h','e','l','l','o',] - .emit_strings = 1, .skip_names = 0: (char[6])"hello" - .emit_strings = 1, .skip_names = 1: "hello" Here's the string "h\xff", dumped with .compact = 1 and .skip_names = 1: - .emit_strings = 0: ['h',-1,] - .emit_strings = 1: "h\xff" Signed-off-by: Blake Jones <blakejones(a)google.com> --- tools/lib/bpf/btf.h | 3 ++- tools/lib/bpf/btf_dump.c | 55 +++++++++++++++++++++++++++++++++++++++- 2 files changed, 56 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 4392451d634b..ccfd905f03df 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -326,9 +326,10 @@ struct btf_dump_type_data_opts { bool compact; /* no newlines/indentation */ bool skip_names; /* skip member/type names */ bool emit_zeroes; /* show 0-valued fields */ + bool emit_strings; /* print char arrays as strings */ size_t :0; }; -#define btf_dump_type_data_opts__last_field emit_zeroes +#define btf_dump_type_data_opts__last_field emit_strings LIBBPF_API int btf_dump__dump_type_data(struct btf_dump *d, __u32 id, diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 460c3e57fadb..7c2f1f13f958 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -68,6 +68,7 @@ struct btf_dump_data { bool compact; bool skip_names; bool emit_zeroes; + bool emit_strings; __u8 indent_lvl; /* base indent level */ char indent_str[BTF_DATA_INDENT_STR_LEN]; /* below are used during iteration */ @@ -2028,6 +2029,52 @@ static int btf_dump_var_data(struct btf_dump *d, return btf_dump_dump_type_data(d, NULL, t, type_id, data, 0, 0); } +static int btf_dump_string_data(struct btf_dump *d, + const struct btf_type *t, + __u32 id, + const void *data) +{ + const struct btf_array *array = btf_array(t); + const char *chars = data; + __u32 i; + + /* Make sure it is a NUL-terminated string. */ + for (i = 0; i < array->nelems; i++) { + if ((void *)(chars + i) >= d->typed_dump->data_end) + return -E2BIG; + if (chars[i] == '\0') + break; + } + if (i == array->nelems) { + /* The caller will print this as a regular array. */ + return -EINVAL; + } + + btf_dump_data_pfx(d); + btf_dump_printf(d, "\""); + + for (i = 0; i < array->nelems; i++) { + char c = chars[i]; + + if (c == '\0') { + /* + * When printing character arrays as strings, NUL bytes + * are always treated as string terminators; they are + * never printed. + */ + break; + } + if (isprint(c)) + btf_dump_printf(d, "%c", c); + else + btf_dump_printf(d, "\\x%02x", (__u8)c); + } + + btf_dump_printf(d, "\""); + + return 0; +} + static int btf_dump_array_data(struct btf_dump *d, const struct btf_type *t, __u32 id, @@ -2055,8 +2102,13 @@ static int btf_dump_array_data(struct btf_dump *d, * char arrays, so if size is 1 and element is * printable as a char, we'll do that. */ - if (elem_size == 1) + if (elem_size == 1) { + if (d->typed_dump->emit_strings && + btf_dump_string_data(d, t, id, data) == 0) { + return 0; + } d->typed_dump->is_array_char = true; + } } /* note that we increment depth before calling btf_dump_print() below; @@ -2544,6 +2596,7 @@ int btf_dump__dump_type_data(struct btf_dump *d, __u32 id, d->typed_dump->compact = OPTS_GET(opts, compact, false); d->typed_dump->skip_names = OPTS_GET(opts, skip_names, false); d->typed_dump->emit_zeroes = OPTS_GET(opts, emit_zeroes, false); + d->typed_dump->emit_strings = OPTS_GET(opts, emit_strings, false); ret = btf_dump_dump_type_data(d, NULL, t, id, data, 0, 0); -- 2.49.0.1204.g71687c7c1d-goog

1 month, 3 weeks

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[PATCH v2 7/7] selftests: kselftest: Add ulong typedef for non-glibc compatibility

by Aqib Faruqui

Some C libraries may not define the ulong typedef that is commonly available as a BSD/GNU extension. Add a fallback typedef to ensure ulong is available across all selftest environments. Signed-off-by: Aqib Faruqui <aqibaf(a)amazon.com> --- tools/testing/selftests/kselftest.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h index f362c6766..a1088a2af 100644 --- a/tools/testing/selftests/kselftest.h +++ b/tools/testing/selftests/kselftest.h @@ -58,6 +58,11 @@ #include <stdio.h> #include <sys/utsname.h> #include <sys/syscall.h> +#include <sys/types.h> +#endif + +#ifndef ulong +typedef unsigned long ulong; #endif #ifndef ARRAY_SIZE -- 2.47.3

1 month, 3 weeks

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[PATCH v2 6/7] selftests: Fix stdbuf compatibility in mixed libc environments

by Aqib Faruqui

The original stdbuf use only checked if /usr/bin/stdbuf exists in the host's system but failed to verify compatibility between stdbuf and the target test binary. The issue occurs when: - Host system has glibc-based stdbuf from coreutils - Selftest binaries are compiled with a non-glibc toolchain (cross compilation) The fix adds a runtime compatibility test against the target test binary before enabling stdbuf, enabling cross-compiled selftests to run successfully. Signed-off-by: Aqib Faruqui <aqibaf(a)amazon.com> --- tools/testing/selftests/kselftest/runner.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/kselftest/runner.sh b/tools/testing/selftests/kselftest/runner.sh index 2c3c58e65..8d4e33bd5 100644 --- a/tools/testing/selftests/kselftest/runner.sh +++ b/tools/testing/selftests/kselftest/runner.sh @@ -107,7 +107,7 @@ run_one() echo "# Warning: file $TEST is missing!" echo "not ok $test_num $TEST_HDR_MSG" else - if [ -x /usr/bin/stdbuf ]; then + if [ -x /usr/bin/stdbuf ] && [ -x "$TEST" ] && /usr/bin/stdbuf --output=L ldd "$TEST" >/dev/null 2>&1; then stdbuf="/usr/bin/stdbuf --output=L " fi eval kselftest_cmd_args="\$${kselftest_cmd_args_ref:-}" -- 2.47.3

1 month, 3 weeks

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[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 month, 3 weeks

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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 month, 3 weeks

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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 month, 3 weeks

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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 month, 3 weeks

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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 month, 3 weeks

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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 month, 3 weeks

4
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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

1 month, 4 weeks

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Linux-kselftest-mirror September 2025