September 2025 - Linux-kselftest-mirror

[PATCH bpf-next v2 0/2] bpf: Add kfunc bpf_strcasecmp()

by Rong Tao

Kfunc already support bpf_strcmp, this patchset introduce bpf_strcasecmp and add some selftests. Rong Tao (2): bpf: add bpf_strcasecmp kfunc selftests/bpf: Test kfunc bpf_strcasecmp kernel/bpf/helpers.c | 68 +++++++++++++------ .../bpf/progs/string_kfuncs_failure1.c | 6 ++ .../bpf/progs/string_kfuncs_failure2.c | 1 + .../bpf/progs/string_kfuncs_success.c | 5 ++ 4 files changed, 60 insertions(+), 20 deletions(-) --- v2: Remove __ign prefix from __bpf_strcasecmp and add E2BIG failure test; v1: https://lore.kernel.org/lkml/tencent_5AE811A28781BE106AD6CDE59F4ADD2BFA06@q… -- 2.51.0

3 months

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[PATCH bpf-next 1/2] bpf: add bpf_strcasecmp kfunc

by Rong Tao

From: Rong Tao <rongtao(a)cestc.cn> bpf_strcasecmp() function performs same like bpf_strcmp() except ignoring the case of the characters. Signed-off-by: Rong Tao <rongtao(a)cestc.cn> --- kernel/bpf/helpers.c | 56 +++++++++++++++++++++++++++++++++----------- 1 file changed, 42 insertions(+), 14 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 401b4932cc49..e807a708e5fc 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3349,20 +3349,7 @@ __bpf_kfunc void __bpf_trap(void) * __get_kernel_nofault instead of plain dereference to make them safe. */ -/** - * bpf_strcmp - Compare two strings - * @s1__ign: One string - * @s2__ign: Another string - * - * Return: - * * %0 - Strings are equal - * * %-1 - @s1__ign is smaller - * * %1 - @s2__ign is smaller - * * %-EFAULT - Cannot read one of the strings - * * %-E2BIG - One of strings is too large - * * %-ERANGE - One of strings is outside of kernel address space - */ -__bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign) +int __bpf_strcasecmp(const char *s1__ign, const char *s2__ign, bool ignore_case) { char c1, c2; int i; @@ -3376,6 +3363,10 @@ __bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign) for (i = 0; i < XATTR_SIZE_MAX; i++) { __get_kernel_nofault(&c1, s1__ign, char, err_out); __get_kernel_nofault(&c2, s2__ign, char, err_out); + if (ignore_case) { + c1 = tolower(c1); + c2 = tolower(c2); + } if (c1 != c2) return c1 < c2 ? -1 : 1; if (c1 == '\0') @@ -3388,6 +3379,42 @@ __bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign) return -EFAULT; } +/** + * bpf_strcmp - Compare two strings + * @s1__ign: One string + * @s2__ign: Another string + * + * Return: + * * %0 - Strings are equal + * * %-1 - @s1__ign is smaller + * * %1 - @s2__ign is smaller + * * %-EFAULT - Cannot read one of the strings + * * %-E2BIG - One of strings is too large + * * %-ERANGE - One of strings is outside of kernel address space + */ +__bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign) +{ + return __bpf_strcasecmp(s1__ign, s2__ign, false); +} + +/** + * bpf_strcasecmp - Compare two strings, ignoring the case of the characters + * @s1__ign: One string + * @s2__ign: Another string + * + * Return: + * * %0 - Strings are equal + * * %-1 - @s1__ign is smaller + * * %1 - @s2__ign is smaller + * * %-EFAULT - Cannot read one of the strings + * * %-E2BIG - One of strings is too large + * * %-ERANGE - One of strings is outside of kernel address space + */ +__bpf_kfunc int bpf_strcasecmp(const char *s1__ign, const char *s2__ign) +{ + return __bpf_strcasecmp(s1__ign, s2__ign, true); +} + /** * bpf_strnchr - Find a character in a length limited string * @s__ign: The string to be searched @@ -3832,6 +3859,7 @@ BTF_ID_FLAGS(func, bpf_iter_dmabuf_destroy, KF_ITER_DESTROY | KF_SLEEPABLE) #endif BTF_ID_FLAGS(func, __bpf_trap) BTF_ID_FLAGS(func, bpf_strcmp); +BTF_ID_FLAGS(func, bpf_strcasecmp); BTF_ID_FLAGS(func, bpf_strchr); BTF_ID_FLAGS(func, bpf_strchrnul); BTF_ID_FLAGS(func, bpf_strnchr); -- 2.51.0

3 months

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[PATCH bpf-next 2/2] selftests/bpf: Test kfunc bpf_strcasecmp

by Rong Tao

From: Rong Tao <rongtao(a)cestc.cn> Add testsuites for kfunc bpf_strcasecmp. Signed-off-by: Rong Tao <rongtao(a)cestc.cn> --- tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c | 6 ++++++ tools/testing/selftests/bpf/progs/string_kfuncs_success.c | 5 +++++ 2 files changed, 11 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c b/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c index 53af438bd998..99d72c68f76a 100644 --- a/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c +++ b/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c @@ -31,6 +31,8 @@ char *invalid_kern_ptr = (char *)-1; /* Passing NULL to string kfuncs (treated as a userspace ptr) */ SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_null1(void *ctx) { return bpf_strcmp(NULL, "hello"); } SEC("syscall") __retval(USER_PTR_ERR)int test_strcmp_null2(void *ctx) { return bpf_strcmp("hello", NULL); } +SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_null1(void *ctx) { return bpf_strcasecmp(NULL, "HELLO"); } +SEC("syscall") __retval(USER_PTR_ERR)int test_strcasecmp_null2(void *ctx) { return bpf_strcasecmp("HELLO", NULL); } SEC("syscall") __retval(USER_PTR_ERR)int test_strchr_null(void *ctx) { return bpf_strchr(NULL, 'a'); } SEC("syscall") __retval(USER_PTR_ERR)int test_strchrnul_null(void *ctx) { return bpf_strchrnul(NULL, 'a'); } SEC("syscall") __retval(USER_PTR_ERR)int test_strnchr_null(void *ctx) { return bpf_strnchr(NULL, 1, 'a'); } @@ -49,6 +51,8 @@ SEC("syscall") __retval(USER_PTR_ERR)int test_strnstr_null2(void *ctx) { return /* Passing userspace ptr to string kfuncs */ SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_user_ptr1(void *ctx) { return bpf_strcmp(user_ptr, "hello"); } SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_user_ptr2(void *ctx) { return bpf_strcmp("hello", user_ptr); } +SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_user_ptr1(void *ctx) { return bpf_strcasecmp(user_ptr, "HELLO"); } +SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_user_ptr2(void *ctx) { return bpf_strcasecmp("HELLO", user_ptr); } SEC("syscall") __retval(USER_PTR_ERR) int test_strchr_user_ptr(void *ctx) { return bpf_strchr(user_ptr, 'a'); } SEC("syscall") __retval(USER_PTR_ERR) int test_strchrnul_user_ptr(void *ctx) { return bpf_strchrnul(user_ptr, 'a'); } SEC("syscall") __retval(USER_PTR_ERR) int test_strnchr_user_ptr(void *ctx) { return bpf_strnchr(user_ptr, 1, 'a'); } @@ -69,6 +73,8 @@ SEC("syscall") __retval(USER_PTR_ERR) int test_strnstr_user_ptr2(void *ctx) { re /* Passing invalid kernel ptr to string kfuncs should always return -EFAULT */ SEC("syscall") __retval(-EFAULT) int test_strcmp_pagefault1(void *ctx) { return bpf_strcmp(invalid_kern_ptr, "hello"); } SEC("syscall") __retval(-EFAULT) int test_strcmp_pagefault2(void *ctx) { return bpf_strcmp("hello", invalid_kern_ptr); } +SEC("syscall") __retval(-EFAULT) int test_strcasecmp_pagefault1(void *ctx) { return bpf_strcasecmp(invalid_kern_ptr, "HELLO"); } +SEC("syscall") __retval(-EFAULT) int test_strcasecmp_pagefault2(void *ctx) { return bpf_strcasecmp("HELLO", invalid_kern_ptr); } SEC("syscall") __retval(-EFAULT) int test_strchr_pagefault(void *ctx) { return bpf_strchr(invalid_kern_ptr, 'a'); } SEC("syscall") __retval(-EFAULT) int test_strchrnul_pagefault(void *ctx) { return bpf_strchrnul(invalid_kern_ptr, 'a'); } SEC("syscall") __retval(-EFAULT) int test_strnchr_pagefault(void *ctx) { return bpf_strnchr(invalid_kern_ptr, 1, 'a'); } diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c index 46697f381878..67830456637b 100644 --- a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c +++ b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c @@ -12,6 +12,11 @@ char str[] = "hello world"; /* Functional tests */ __test(0) int test_strcmp_eq(void *ctx) { return bpf_strcmp(str, "hello world"); } __test(1) int test_strcmp_neq(void *ctx) { return bpf_strcmp(str, "hello"); } +__test(0) int test_strcasecmp_eq1(void *ctx) { return bpf_strcasecmp(str, "hello world"); } +__test(0) int test_strcasecmp_eq2(void *ctx) { return bpf_strcasecmp(str, "HELLO WORLD"); } +__test(0) int test_strcasecmp_eq3(void *ctx) { return bpf_strcasecmp(str, "HELLO world"); } +__test(1) int test_strcasecmp_neq1(void *ctx) { return bpf_strcasecmp(str, "hello"); } +__test(1) int test_strcasecmp_neq2(void *ctx) { return bpf_strcasecmp(str, "HELLO"); } __test(1) int test_strchr_found(void *ctx) { return bpf_strchr(str, 'e'); } __test(11) int test_strchr_null(void *ctx) { return bpf_strchr(str, '\0'); } __test(-ENOENT) int test_strchr_notfound(void *ctx) { return bpf_strchr(str, 'x'); } -- 2.51.0

3 months

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[PATCH bpf-next 0/2] bpf: Add kfunc bpf_strcasecmp()

by Rong Tao

From: Rong Tao <rongtao(a)cestc.cn> Kfunc already support bpf_strcmp, this patchset introduce bpf_strcasecmp and add some selftests. Rong Tao (2): bpf: add bpf_strcasecmp kfunc selftests/bpf: Test kfunc bpf_strcasecmp kernel/bpf/helpers.c | 56 ++++++++++++++----- .../bpf/progs/string_kfuncs_failure1.c | 6 ++ .../bpf/progs/string_kfuncs_success.c | 5 ++ 3 files changed, 53 insertions(+), 14 deletions(-) -- 2.51.0

3 months

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[PATCH] selftests: net: fix spelling and grammar mistakes

by Praveen Balakrishnan

Fix several spelling and grammatical mistakes in output messages from the net selftests to improve readability. Only the message strings for the test output have been modified. No changes to the functional logic of the tests have been made. Signed-off-by: Praveen Balakrishnan <praveen.balakrishnan(a)magd.ox.ac.uk> --- tools/testing/selftests/net/openvswitch/ovs-dpctl.py | 2 +- tools/testing/selftests/net/rps_default_mask.sh | 12 ++++++------ 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py index 8a0396bfaf99..b521e0dea506 100644 --- a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py +++ b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py @@ -1877,7 +1877,7 @@ class OvsPacket(GenericNetlinkSocket): elif msg["cmd"] == OvsPacket.OVS_PACKET_CMD_EXECUTE: up.execute(msg) else: - print("Unkonwn cmd: %d" % msg["cmd"]) + print("Unknown cmd: %d" % msg["cmd"]) except NetlinkError as ne: raise ne diff --git a/tools/testing/selftests/net/rps_default_mask.sh b/tools/testing/selftests/net/rps_default_mask.sh index 4287a8529890..b200019b3c80 100755 --- a/tools/testing/selftests/net/rps_default_mask.sh +++ b/tools/testing/selftests/net/rps_default_mask.sh @@ -54,16 +54,16 @@ cleanup echo 1 > /proc/sys/net/core/rps_default_mask setup -chk_rps "changing rps_default_mask dont affect existing devices" "" lo $INITIAL_RPS_DEFAULT_MASK +chk_rps "changing rps_default_mask doesn't affect existing devices" "" lo $INITIAL_RPS_DEFAULT_MASK echo 3 > /proc/sys/net/core/rps_default_mask -chk_rps "changing rps_default_mask dont affect existing netns" $NETNS lo 0 +chk_rps "changing rps_default_mask doesn't affect existing netns" $NETNS lo 0 ip link add name $VETH type veth peer netns $NETNS name $VETH ip link set dev $VETH up ip -n $NETNS link set dev $VETH up -chk_rps "changing rps_default_mask affect newly created devices" "" $VETH 3 -chk_rps "changing rps_default_mask don't affect newly child netns[II]" $NETNS $VETH 0 +chk_rps "changing rps_default_mask affects newly created devices" "" $VETH 3 +chk_rps "changing rps_default_mask doesn't affect newly child netns[II]" $NETNS $VETH 0 ip link del dev $VETH ip netns del $NETNS @@ -72,8 +72,8 @@ chk_rps "rps_default_mask is 0 by default in child netns" "$NETNS" lo 0 ip netns exec $NETNS sysctl -qw net.core.rps_default_mask=1 ip link add name $VETH type veth peer netns $NETNS name $VETH -chk_rps "changing rps_default_mask in child ns don't affect the main one" "" lo $INITIAL_RPS_DEFAULT_MASK +chk_rps "changing rps_default_mask in child ns doesn't affect the main one" "" lo $INITIAL_RPS_DEFAULT_MASK chk_rps "changing rps_default_mask in child ns affects new childns devices" $NETNS $VETH 1 -chk_rps "changing rps_default_mask in child ns don't affect existing devices" $NETNS lo 0 +chk_rps "changing rps_default_mask in child ns doesn't affect existing devices" $NETNS lo 0 exit $ret -- 2.39.5

3 months

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[RFC PATCH v2 bpf-next 0/3] bpf: cgroup: support writing and freezing cgroups from BPF

by Djalal Harouni

This patch series add support to write cgroup interfaces from BPF. It is useful to freeze a cgroup hierarchy on suspicious activity for a more thorough analysis before killing it. Planned users of this feature are: systemd and BPF tools where the cgroup hierarchy could be a system service, user session, k8s pod or a container. The writing happens via kernfs nodes and the cgroup must be on the default hierarchy. It implements the requests and feedback from v1 [1] where now we use a unified path for cgroup user space and BPF writing. So I want to validate that this is the right approach first. Todo: * Limit size of data to be written. * Further tests. * Add cgroup kill support. # RFC v1 -> v2 * Implemented Alexei and Tejun requests [1]. * Unified path where user space or BPF writing end up taking directly a kernfs_node with an example on the "cgroup.freeze" interface. [1] https://lore.kernel.org/bpf/20240327225334.58474-1-tixxdz@gmail.com/ Djalal Harouni (3): kernfs: cgroup: support writing cgroup interfaces from a kernfs node bpf: cgroup: Add BPF Kfunc to write cgroup interfaces selftests/bpf: add selftest for bpf_cgroup_write_interface include/linux/cgroup.h | 3 ++ kernel/bpf/helpers.c | 45 +++++ kernel/cgroup/cgroup.c | 102 +++++++ tools/testing/selftests/bpf/prog_tests/task_freeze_cgroup.c | 172 ++++++++++++ tools/testing/selftests/bpf/progs/test_task_freeze_cgroup.c | 155 ++++++++++ 5 files changed, 471 insertions(+), 6 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/task_freeze_cgroup.c create mode 100644 tools/testing/selftests/bpf/progs/test_task_freeze_cgroup.c -- 2.34.1

3 months

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[PATCH net] selftests: drv-net: csum: fix interface name for remote host

by Jakub Kicinski

Use cfg.remote_ifname for arguments of remote command. Without this UDP tests fail in NIPA where local interface is called enp1s0 and remote enp0s4. Fixes: 1d0dc857b5d8 ("selftests: drv-net: add checksum tests") Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> --- CC: shuah(a)kernel.org CC: willemb(a)google.com CC: petrm(a)nvidia.com CC: linux-kselftest(a)vger.kernel.org --- tools/testing/selftests/drivers/net/hw/csum.py | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/drivers/net/hw/csum.py b/tools/testing/selftests/drivers/net/hw/csum.py index cd23af875317..3e3a89a34afe 100755 --- a/tools/testing/selftests/drivers/net/hw/csum.py +++ b/tools/testing/selftests/drivers/net/hw/csum.py @@ -17,7 +17,7 @@ from lib.py import bkg, cmd, wait_port_listen ip_args = f"-{ipver} -S {cfg.remote_addr_v[ipver]} -D {cfg.addr_v[ipver]}" rx_cmd = f"{cfg.bin_local} -i {cfg.ifname} -n 100 {ip_args} -r 1 -R {extra_args}" - tx_cmd = f"{cfg.bin_remote} -i {cfg.ifname} -n 100 {ip_args} -r 1 -T {extra_args}" + tx_cmd = f"{cfg.bin_remote} -i {cfg.remote_ifname} -n 100 {ip_args} -r 1 -T {extra_args}" with bkg(rx_cmd, exit_wait=True): wait_port_listen(34000, proto="udp") @@ -37,7 +37,7 @@ from lib.py import bkg, cmd, wait_port_listen if extra_args != "-U -Z": extra_args += " -r 1" - rx_cmd = f"{cfg.bin_remote} -i {cfg.ifname} -L 1 -n 100 {ip_args} -R {extra_args}" + rx_cmd = f"{cfg.bin_remote} -i {cfg.remote_ifname} -L 1 -n 100 {ip_args} -R {extra_args}" tx_cmd = f"{cfg.bin_local} -i {cfg.ifname} -L 1 -n 100 {ip_args} -T {extra_args}" with bkg(rx_cmd, host=cfg.remote, exit_wait=True): -- 2.51.0

3 months

4
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[PATCH v4 0/2] KVM: guest_memfd: use write for population

by Kalyazin, Nikita

[ based on kvm/next ] Implement guest_memfd allocation and population via the write syscall. This is useful in non-CoCo use cases where the host can access guest memory. Even though the same can also be achieved via userspace mapping and memcpying from userspace, write provides a more performant option because it does not need to set page tables and it does not cause a page fault for every page like memcpy would. Note that memcpy cannot be accelerated via MADV_POPULATE_WRITE as it is not supported by guest_memfd and relies on GUP. Populating 512MiB of guest_memfd on a x86 machine: - via memcpy: 436 ms - via write: 202 ms (-54%) v4: - Switch from implementing the write callback to write_iter - Remove conditional compilation - Rebase to kvm/next v3: - https://lore.kernel.org/kvm/20250303130838.28812-1-kalyazin@amazon.com - David/Mike D: Only compile support for the write syscall if CONFIG_KVM_GMEM_SHARED_MEM (now gone) is enabled. v2: - https://lore.kernel.org/kvm/20241129123929.64790-1-kalyazin@amazon.com - Switch from an ioctl to the write syscall to implement population v1: - https://lore.kernel.org/kvm/20241024095429.54052-1-kalyazin@amazon.com Nikita Kalyazin (2): KVM: guest_memfd: add generic population via write KVM: selftests: update guest_memfd write tests .../testing/selftests/kvm/guest_memfd_test.c | 85 +++++++++++++++++-- virt/kvm/guest_memfd.c | 64 +++++++++++++- 2 files changed, 142 insertions(+), 7 deletions(-) base-commit: a6ad54137af92535cfe32e19e5f3bc1bb7dbd383 -- 2.50.1

3 months

4
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[PATCH net-next v4] 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> --- 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 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 | 144 ++++++++++++++++++ 3 files changed, 146 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..6d1311e26501 --- /dev/null +++ b/tools/testing/selftests/net/ipv6_fragmentation.c @@ -0,0 +1,144 @@ +// 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 <fcntl.h> +#include <linux/if_tun.h> +#include <net/if.h> +#include <netinet/in.h> +#include <sched.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ioctl.h> +#include <sys/socket.h> +#include <unistd.h> +#include "../kselftest.h" + +#define MTU 1500 +#define LARGER_THAN_MTU 8192 + +/* bring up interface */ +static int interface_up(int ctl, struct ifreq *ifr) +{ + if (ioctl(ctl, SIOCGIFFLAGS, ifr) == -1) + error(KSFT_FAIL, errno, "ioctl SIOCGIFFLAGS"); + ifr->ifr_flags = ifr->ifr_flags | IFF_UP; + return ioctl(ctl, SIOCSIFFLAGS, ifr); +} + +/* no need to wait for DAD in our namespace */ +static int disable_dad(char *ifname) +{ + char sysvar[] = "/proc/sys/net/ipv6/conf/%s/accept_dad"; + char fname[IFNAMSIZ + sizeof(sysvar)]; + int fd; + + snprintf(fname, sizeof(fname), sysvar, ifname); + fd = open(fname, O_WRONLY); + if (fd == -1) + error(KSFT_FAIL, errno, "open accept_dad"); + if (write(fd, "0", 1) != 1) + error(KSFT_FAIL, errno, "write accept_dad"); + + return close(fd); +} + +static int setup(void) +{ + struct ifreq ifr = { + .ifr_name = "lo" + }; + int fd = -1; + 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"); + + disable_dad("lo"); + interface_up(ctl, &ifr); + + close(ctl); + return fd; +} + +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) */ + }; + 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 ns_fd; + int err = KSFT_FAIL; + int s; + + printf("Testing IPv6 fragmentation\n"); + ns_fd = 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; + } + printf("[FAIL] sendmsg: %s\n", strerror(errno)); + } else if (rc != LARGER_THAN_MTU) { + printf("[FAIL] sendmsg() returned %zi, expected %i\n", rc, LARGER_THAN_MTU); + } else { + printf("[PASS] sendmsg() returned %zi\n", rc); + err = KSFT_PASS; + } + close(s); + close(ns_fd); + return err; +} base-commit: 864ecc4a6dade82d3f70eab43dad0e277aa6fc78 -- 2.49.1

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[PATCH 2/9] KVM: selftests: Add __packed attribute fallback

by Aqib Faruqui

Kernel UAPI headers use __packed but don't provide the definition in userspace builds. Add a fallback definition matching the kernel's implementation. This follows the same pattern used by BPF and SGX selftests. Signed-off-by: Aqib Faruqui <aqibaf(a)amazon.com> --- tools/testing/selftests/kvm/include/kvm_util.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h index 23a506d7e..7fae7f5e7 100644 --- a/tools/testing/selftests/kvm/include/kvm_util.h +++ b/tools/testing/selftests/kvm/include/kvm_util.h @@ -5,6 +5,10 @@ #ifndef SELFTEST_KVM_UTIL_H #define SELFTEST_KVM_UTIL_H +#ifndef __packed +#define __packed __attribute__((__packed__)) +#endif + #include "test_util.h" #include <linux/compiler.h> -- 2.47.3

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Linux-kselftest-mirror September 2025