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

[PATCH AUTOSEL 6.12 01/20] selftests/bpf: Fix stdout race condition in traffic monitor

by Sasha Levin

From: Amery Hung <ameryhung(a)gmail.com> [ Upstream commit b99f27e90268b1a814c13f8bd72ea1db448ea257 ] Fix a race condition between the main test_progs thread and the traffic monitoring thread. The traffic monitor thread tries to print a line using multiple printf and use flockfile() to prevent the line from being torn apart. Meanwhile, the main thread doing io redirection can reassign or close stdout when going through tests. A deadlock as shown below can happen. main traffic_monitor_thread ==== ====================== show_transport() -> flockfile(stdout) stdio_hijack_init() -> stdout = open_memstream(log_buf, log_cnt); ... env.subtest_state->stdout_saved = stdout; ... funlockfile(stdout) stdio_restore_cleanup() -> fclose(env.subtest_state->stdout_saved); After the traffic monitor thread lock stdout, A new memstream can be assigned to stdout by the main thread. Therefore, the traffic monitor thread later will not be able to unlock the original stdout. As the main thread tries to access the old stdout, it will hang indefinitely as it is still locked by the traffic monitor thread. The deadlock can be reproduced by running test_progs repeatedly with traffic monitor enabled: for ((i=1;i<=100;i++)); do ./test_progs -a flow_dissector_skb* -m '*' done Fix this by only calling printf once and remove flockfile()/funlockfile(). Signed-off-by: Amery Hung <ameryhung(a)gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau(a)kernel.org> Link: https://patch.msgid.link/20250213233217.553258-1-ameryhung@gmail.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/network_helpers.c | 33 ++++++++----------- 1 file changed, 13 insertions(+), 20 deletions(-) diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c index 27784946b01b8..af0ee70a53f9f 100644 --- a/tools/testing/selftests/bpf/network_helpers.c +++ b/tools/testing/selftests/bpf/network_helpers.c @@ -771,12 +771,13 @@ static const char *pkt_type_str(u16 pkt_type) return "Unknown"; } +#define MAX_FLAGS_STRLEN 21 /* Show the information of the transport layer in the packet */ static void show_transport(const u_char *packet, u16 len, u32 ifindex, const char *src_addr, const char *dst_addr, u16 proto, bool ipv6, u8 pkt_type) { - char *ifname, _ifname[IF_NAMESIZE]; + char *ifname, _ifname[IF_NAMESIZE], flags[MAX_FLAGS_STRLEN] = ""; const char *transport_str; u16 src_port, dst_port; struct udphdr *udp; @@ -817,29 +818,21 @@ static void show_transport(const u_char *packet, u16 len, u32 ifindex, /* TCP or UDP*/ - flockfile(stdout); + if (proto == IPPROTO_TCP) + snprintf(flags, MAX_FLAGS_STRLEN, "%s%s%s%s", + tcp->fin ? ", FIN" : "", + tcp->syn ? ", SYN" : "", + tcp->rst ? ", RST" : "", + tcp->ack ? ", ACK" : ""); + if (ipv6) - printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d", + printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); + dst_addr, dst_port, transport_str, len, flags); else - printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d", + printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); - - if (proto == IPPROTO_TCP) { - if (tcp->fin) - printf(", FIN"); - if (tcp->syn) - printf(", SYN"); - if (tcp->rst) - printf(", RST"); - if (tcp->ack) - printf(", ACK"); - } - - printf("\n"); - funlockfile(stdout); + dst_addr, dst_port, transport_str, len, flags); } static void show_ipv6_packet(const u_char *packet, u32 ifindex, u8 pkt_type) -- 2.39.5

8 months, 1 week

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[PATCH AUTOSEL 6.13 16/22] selftests/bpf: Fix cap_enable_effective() return code

by Sasha Levin

From: Feng Yang <yangfeng(a)kylinos.cn> [ Upstream commit 339c1f8ea11cc042c30c315c1a8f61e4b8a90117 ] The caller of cap_enable_effective() expects negative error code. Fix it. Before: failed to restore CAP_SYS_ADMIN: -1, Unknown error -1 After: failed to restore CAP_SYS_ADMIN: -3, No such process failed to restore CAP_SYS_ADMIN: -22, Invalid argument Signed-off-by: Feng Yang <yangfeng(a)kylinos.cn> Acked-by: Eduard Zingerman <eddyz87(a)gmail.com> Link: https://lore.kernel.org/r/20250305022234.44932-1-yangfeng59949@163.com Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/cap_helpers.c | 8 ++++---- tools/testing/selftests/bpf/cap_helpers.h | 1 + tools/testing/selftests/bpf/prog_tests/verifier.c | 4 ++-- tools/testing/selftests/bpf/test_loader.c | 6 +++--- 4 files changed, 10 insertions(+), 9 deletions(-) diff --git a/tools/testing/selftests/bpf/cap_helpers.c b/tools/testing/selftests/bpf/cap_helpers.c index d5ac507401d7c..98f840c3a38f7 100644 --- a/tools/testing/selftests/bpf/cap_helpers.c +++ b/tools/testing/selftests/bpf/cap_helpers.c @@ -19,7 +19,7 @@ int cap_enable_effective(__u64 caps, __u64 *old_caps) err = capget(&hdr, data); if (err) - return err; + return -errno; if (old_caps) *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective; @@ -32,7 +32,7 @@ int cap_enable_effective(__u64 caps, __u64 *old_caps) data[1].effective |= cap1; err = capset(&hdr, data); if (err) - return err; + return -errno; return 0; } @@ -49,7 +49,7 @@ int cap_disable_effective(__u64 caps, __u64 *old_caps) err = capget(&hdr, data); if (err) - return err; + return -errno; if (old_caps) *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective; @@ -61,7 +61,7 @@ int cap_disable_effective(__u64 caps, __u64 *old_caps) data[1].effective &= ~cap1; err = capset(&hdr, data); if (err) - return err; + return -errno; return 0; } diff --git a/tools/testing/selftests/bpf/cap_helpers.h b/tools/testing/selftests/bpf/cap_helpers.h index 6d163530cb0fd..8dcb28557f762 100644 --- a/tools/testing/selftests/bpf/cap_helpers.h +++ b/tools/testing/selftests/bpf/cap_helpers.h @@ -4,6 +4,7 @@ #include <linux/types.h> #include <linux/capability.h> +#include <errno.h> #ifndef CAP_PERFMON #define CAP_PERFMON 38 diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c index 3ee40ee9413a9..88cb75b65cecd 100644 --- a/tools/testing/selftests/bpf/prog_tests/verifier.c +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c @@ -118,7 +118,7 @@ static void run_tests_aux(const char *skel_name, /* test_verifier tests are executed w/o CAP_SYS_ADMIN, do the same here */ err = cap_disable_effective(1ULL << CAP_SYS_ADMIN, &old_caps); if (err) { - PRINT_FAIL("failed to drop CAP_SYS_ADMIN: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to drop CAP_SYS_ADMIN: %i, %s\n", err, strerror(-err)); return; } @@ -128,7 +128,7 @@ static void run_tests_aux(const char *skel_name, err = cap_enable_effective(old_caps, NULL); if (err) - PRINT_FAIL("failed to restore CAP_SYS_ADMIN: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to restore CAP_SYS_ADMIN: %i, %s\n", err, strerror(-err)); } #define RUN(skel) run_tests_aux(#skel, skel##__elf_bytes, NULL) diff --git a/tools/testing/selftests/bpf/test_loader.c b/tools/testing/selftests/bpf/test_loader.c index 53b06647cf57d..8a403e5aa3145 100644 --- a/tools/testing/selftests/bpf/test_loader.c +++ b/tools/testing/selftests/bpf/test_loader.c @@ -773,7 +773,7 @@ static int drop_capabilities(struct cap_state *caps) err = cap_disable_effective(caps_to_drop, &caps->old_caps); if (err) { - PRINT_FAIL("failed to drop capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to drop capabilities: %i, %s\n", err, strerror(-err)); return err; } @@ -790,7 +790,7 @@ static int restore_capabilities(struct cap_state *caps) err = cap_enable_effective(caps->old_caps, NULL); if (err) - PRINT_FAIL("failed to restore capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to restore capabilities: %i, %s\n", err, strerror(-err)); caps->initialized = false; return err; } @@ -959,7 +959,7 @@ void run_subtest(struct test_loader *tester, if (subspec->caps) { err = cap_enable_effective(subspec->caps, NULL); if (err) { - PRINT_FAIL("failed to set capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to set capabilities: %i, %s\n", err, strerror(-err)); goto subtest_cleanup; } } -- 2.39.5

8 months, 1 week

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[PATCH AUTOSEL 6.13 02/22] selftests/bpf: Fix stdout race condition in traffic monitor

by Sasha Levin

From: Amery Hung <ameryhung(a)gmail.com> [ Upstream commit b99f27e90268b1a814c13f8bd72ea1db448ea257 ] Fix a race condition between the main test_progs thread and the traffic monitoring thread. The traffic monitor thread tries to print a line using multiple printf and use flockfile() to prevent the line from being torn apart. Meanwhile, the main thread doing io redirection can reassign or close stdout when going through tests. A deadlock as shown below can happen. main traffic_monitor_thread ==== ====================== show_transport() -> flockfile(stdout) stdio_hijack_init() -> stdout = open_memstream(log_buf, log_cnt); ... env.subtest_state->stdout_saved = stdout; ... funlockfile(stdout) stdio_restore_cleanup() -> fclose(env.subtest_state->stdout_saved); After the traffic monitor thread lock stdout, A new memstream can be assigned to stdout by the main thread. Therefore, the traffic monitor thread later will not be able to unlock the original stdout. As the main thread tries to access the old stdout, it will hang indefinitely as it is still locked by the traffic monitor thread. The deadlock can be reproduced by running test_progs repeatedly with traffic monitor enabled: for ((i=1;i<=100;i++)); do ./test_progs -a flow_dissector_skb* -m '*' done Fix this by only calling printf once and remove flockfile()/funlockfile(). Signed-off-by: Amery Hung <ameryhung(a)gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau(a)kernel.org> Link: https://patch.msgid.link/20250213233217.553258-1-ameryhung@gmail.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/network_helpers.c | 33 ++++++++----------- 1 file changed, 13 insertions(+), 20 deletions(-) diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c index 27784946b01b8..af0ee70a53f9f 100644 --- a/tools/testing/selftests/bpf/network_helpers.c +++ b/tools/testing/selftests/bpf/network_helpers.c @@ -771,12 +771,13 @@ static const char *pkt_type_str(u16 pkt_type) return "Unknown"; } +#define MAX_FLAGS_STRLEN 21 /* Show the information of the transport layer in the packet */ static void show_transport(const u_char *packet, u16 len, u32 ifindex, const char *src_addr, const char *dst_addr, u16 proto, bool ipv6, u8 pkt_type) { - char *ifname, _ifname[IF_NAMESIZE]; + char *ifname, _ifname[IF_NAMESIZE], flags[MAX_FLAGS_STRLEN] = ""; const char *transport_str; u16 src_port, dst_port; struct udphdr *udp; @@ -817,29 +818,21 @@ static void show_transport(const u_char *packet, u16 len, u32 ifindex, /* TCP or UDP*/ - flockfile(stdout); + if (proto == IPPROTO_TCP) + snprintf(flags, MAX_FLAGS_STRLEN, "%s%s%s%s", + tcp->fin ? ", FIN" : "", + tcp->syn ? ", SYN" : "", + tcp->rst ? ", RST" : "", + tcp->ack ? ", ACK" : ""); + if (ipv6) - printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d", + printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); + dst_addr, dst_port, transport_str, len, flags); else - printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d", + printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); - - if (proto == IPPROTO_TCP) { - if (tcp->fin) - printf(", FIN"); - if (tcp->syn) - printf(", SYN"); - if (tcp->rst) - printf(", RST"); - if (tcp->ack) - printf(", ACK"); - } - - printf("\n"); - funlockfile(stdout); + dst_addr, dst_port, transport_str, len, flags); } static void show_ipv6_packet(const u_char *packet, u32 ifindex, u8 pkt_type) -- 2.39.5

8 months, 1 week

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[PATCH AUTOSEL 6.14 17/23] selftests/bpf: Fix cap_enable_effective() return code

by Sasha Levin

From: Feng Yang <yangfeng(a)kylinos.cn> [ Upstream commit 339c1f8ea11cc042c30c315c1a8f61e4b8a90117 ] The caller of cap_enable_effective() expects negative error code. Fix it. Before: failed to restore CAP_SYS_ADMIN: -1, Unknown error -1 After: failed to restore CAP_SYS_ADMIN: -3, No such process failed to restore CAP_SYS_ADMIN: -22, Invalid argument Signed-off-by: Feng Yang <yangfeng(a)kylinos.cn> Acked-by: Eduard Zingerman <eddyz87(a)gmail.com> Link: https://lore.kernel.org/r/20250305022234.44932-1-yangfeng59949@163.com Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/cap_helpers.c | 8 ++++---- tools/testing/selftests/bpf/cap_helpers.h | 1 + tools/testing/selftests/bpf/prog_tests/verifier.c | 4 ++-- tools/testing/selftests/bpf/test_loader.c | 6 +++--- 4 files changed, 10 insertions(+), 9 deletions(-) diff --git a/tools/testing/selftests/bpf/cap_helpers.c b/tools/testing/selftests/bpf/cap_helpers.c index d5ac507401d7c..98f840c3a38f7 100644 --- a/tools/testing/selftests/bpf/cap_helpers.c +++ b/tools/testing/selftests/bpf/cap_helpers.c @@ -19,7 +19,7 @@ int cap_enable_effective(__u64 caps, __u64 *old_caps) err = capget(&hdr, data); if (err) - return err; + return -errno; if (old_caps) *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective; @@ -32,7 +32,7 @@ int cap_enable_effective(__u64 caps, __u64 *old_caps) data[1].effective |= cap1; err = capset(&hdr, data); if (err) - return err; + return -errno; return 0; } @@ -49,7 +49,7 @@ int cap_disable_effective(__u64 caps, __u64 *old_caps) err = capget(&hdr, data); if (err) - return err; + return -errno; if (old_caps) *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective; @@ -61,7 +61,7 @@ int cap_disable_effective(__u64 caps, __u64 *old_caps) data[1].effective &= ~cap1; err = capset(&hdr, data); if (err) - return err; + return -errno; return 0; } diff --git a/tools/testing/selftests/bpf/cap_helpers.h b/tools/testing/selftests/bpf/cap_helpers.h index 6d163530cb0fd..8dcb28557f762 100644 --- a/tools/testing/selftests/bpf/cap_helpers.h +++ b/tools/testing/selftests/bpf/cap_helpers.h @@ -4,6 +4,7 @@ #include <linux/types.h> #include <linux/capability.h> +#include <errno.h> #ifndef CAP_PERFMON #define CAP_PERFMON 38 diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c index 8a0e1ff8a2dc6..ecc320e045513 100644 --- a/tools/testing/selftests/bpf/prog_tests/verifier.c +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c @@ -121,7 +121,7 @@ static void run_tests_aux(const char *skel_name, /* test_verifier tests are executed w/o CAP_SYS_ADMIN, do the same here */ err = cap_disable_effective(1ULL << CAP_SYS_ADMIN, &old_caps); if (err) { - PRINT_FAIL("failed to drop CAP_SYS_ADMIN: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to drop CAP_SYS_ADMIN: %i, %s\n", err, strerror(-err)); return; } @@ -131,7 +131,7 @@ static void run_tests_aux(const char *skel_name, err = cap_enable_effective(old_caps, NULL); if (err) - PRINT_FAIL("failed to restore CAP_SYS_ADMIN: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to restore CAP_SYS_ADMIN: %i, %s\n", err, strerror(-err)); } #define RUN(skel) run_tests_aux(#skel, skel##__elf_bytes, NULL) diff --git a/tools/testing/selftests/bpf/test_loader.c b/tools/testing/selftests/bpf/test_loader.c index 53b06647cf57d..8a403e5aa3145 100644 --- a/tools/testing/selftests/bpf/test_loader.c +++ b/tools/testing/selftests/bpf/test_loader.c @@ -773,7 +773,7 @@ static int drop_capabilities(struct cap_state *caps) err = cap_disable_effective(caps_to_drop, &caps->old_caps); if (err) { - PRINT_FAIL("failed to drop capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to drop capabilities: %i, %s\n", err, strerror(-err)); return err; } @@ -790,7 +790,7 @@ static int restore_capabilities(struct cap_state *caps) err = cap_enable_effective(caps->old_caps, NULL); if (err) - PRINT_FAIL("failed to restore capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to restore capabilities: %i, %s\n", err, strerror(-err)); caps->initialized = false; return err; } @@ -959,7 +959,7 @@ void run_subtest(struct test_loader *tester, if (subspec->caps) { err = cap_enable_effective(subspec->caps, NULL); if (err) { - PRINT_FAIL("failed to set capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to set capabilities: %i, %s\n", err, strerror(-err)); goto subtest_cleanup; } } -- 2.39.5

8 months, 1 week

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[PATCH AUTOSEL 6.14 02/23] selftests/bpf: Fix stdout race condition in traffic monitor

by Sasha Levin

From: Amery Hung <ameryhung(a)gmail.com> [ Upstream commit b99f27e90268b1a814c13f8bd72ea1db448ea257 ] Fix a race condition between the main test_progs thread and the traffic monitoring thread. The traffic monitor thread tries to print a line using multiple printf and use flockfile() to prevent the line from being torn apart. Meanwhile, the main thread doing io redirection can reassign or close stdout when going through tests. A deadlock as shown below can happen. main traffic_monitor_thread ==== ====================== show_transport() -> flockfile(stdout) stdio_hijack_init() -> stdout = open_memstream(log_buf, log_cnt); ... env.subtest_state->stdout_saved = stdout; ... funlockfile(stdout) stdio_restore_cleanup() -> fclose(env.subtest_state->stdout_saved); After the traffic monitor thread lock stdout, A new memstream can be assigned to stdout by the main thread. Therefore, the traffic monitor thread later will not be able to unlock the original stdout. As the main thread tries to access the old stdout, it will hang indefinitely as it is still locked by the traffic monitor thread. The deadlock can be reproduced by running test_progs repeatedly with traffic monitor enabled: for ((i=1;i<=100;i++)); do ./test_progs -a flow_dissector_skb* -m '*' done Fix this by only calling printf once and remove flockfile()/funlockfile(). Signed-off-by: Amery Hung <ameryhung(a)gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau(a)kernel.org> Link: https://patch.msgid.link/20250213233217.553258-1-ameryhung@gmail.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/network_helpers.c | 33 ++++++++----------- 1 file changed, 13 insertions(+), 20 deletions(-) diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c index 80844a5fb1fee..95e943270f359 100644 --- a/tools/testing/selftests/bpf/network_helpers.c +++ b/tools/testing/selftests/bpf/network_helpers.c @@ -771,12 +771,13 @@ static const char *pkt_type_str(u16 pkt_type) return "Unknown"; } +#define MAX_FLAGS_STRLEN 21 /* Show the information of the transport layer in the packet */ static void show_transport(const u_char *packet, u16 len, u32 ifindex, const char *src_addr, const char *dst_addr, u16 proto, bool ipv6, u8 pkt_type) { - char *ifname, _ifname[IF_NAMESIZE]; + char *ifname, _ifname[IF_NAMESIZE], flags[MAX_FLAGS_STRLEN] = ""; const char *transport_str; u16 src_port, dst_port; struct udphdr *udp; @@ -817,29 +818,21 @@ static void show_transport(const u_char *packet, u16 len, u32 ifindex, /* TCP or UDP*/ - flockfile(stdout); + if (proto == IPPROTO_TCP) + snprintf(flags, MAX_FLAGS_STRLEN, "%s%s%s%s", + tcp->fin ? ", FIN" : "", + tcp->syn ? ", SYN" : "", + tcp->rst ? ", RST" : "", + tcp->ack ? ", ACK" : ""); + if (ipv6) - printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d", + printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); + dst_addr, dst_port, transport_str, len, flags); else - printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d", + printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); - - if (proto == IPPROTO_TCP) { - if (tcp->fin) - printf(", FIN"); - if (tcp->syn) - printf(", SYN"); - if (tcp->rst) - printf(", RST"); - if (tcp->ack) - printf(", ACK"); - } - - printf("\n"); - funlockfile(stdout); + dst_addr, dst_port, transport_str, len, flags); } static void show_ipv6_packet(const u_char *packet, u32 ifindex, u8 pkt_type) -- 2.39.5

8 months, 1 week

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[PATCH net-next] net/selftests: Add loopback link local route for self-connect

by Dmitry Safonov via B4 Relay

From: Dmitry Safonov <0x7f454c46(a)gmail.com> self-connect-ipv6 got slightly flaky on netdev: > # timeout set to 120 > # selftests: net/tcp_ao: self-connect_ipv6 > # 1..5 > # # 708[lib/setup.c:250] rand seed 1742872572 > # TAP version 13 > # # 708[lib/proc.c:213] Snmp6 Ip6OutNoRoutes: 0 => 1 > # not ok 1 # error 708[self-connect.c:70] failed to connect() > # ok 2 No unexpected trace events during the test run > # # Planned tests != run tests (5 != 2) > # # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:1 > ok 1 selftests: net/tcp_ao: self-connect_ipv6 I can not reproduce it on my machines, but judging by "Ip6OutNoRoutes" there is no route to the local_addr (::1). Looking at the kernel code, I see that kernel does add link-local address automatically in init_loopback(), but that is called from ipv6 notifier block. So, in turn the userspace that brought up the loopback interface may see rtnetlink ACK earlier than addrconf_notify() does it's job (at least, on a slow VM such as netdev). Probably, for ipv4 it's the same, judging by inetdev_event(). The fix is quite simple: set the link-local route straight after bringing the loopback interface. That will make it synchronous. Signed-off-by: Dmitry Safonov <0x7f454c46(a)gmail.com> --- Sorry to send this during the merge window, it's a test stability fix. It seems that netdev build bot has hit the issue a couple of times, but seems not hitting it constantly at this moment: https://netdev.bots.linux.dev/flakes.html?br-cnt=150&tn-needle=tcp-ao I'm marking it net-next, so that build bot carries it until the merge closes. If it's not fine, I can re-send it after the merge window. --- tools/testing/selftests/net/tcp_ao/self-connect.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/net/tcp_ao/self-connect.c b/tools/testing/selftests/net/tcp_ao/self-connect.c index 73b2f2276f3f5410aaa74bede7f366f81761bd6e..2c73bea698a677f9aedd7bec28f6e7fee7845d2e 100644 --- a/tools/testing/selftests/net/tcp_ao/self-connect.c +++ b/tools/testing/selftests/net/tcp_ao/self-connect.c @@ -16,6 +16,9 @@ static void __setup_lo_intf(const char *lo_intf, if (link_set_up(lo_intf)) test_error("Failed to bring %s up", lo_intf); + + if (ip_route_add(lo_intf, TEST_FAMILY, local_addr, local_addr)) + test_error("Failed to add a local route %s", lo_intf); } static void setup_lo_intf(const char *lo_intf) --- base-commit: 1a9239bb4253f9076b5b4b2a1a4e8d7defd77a95 change-id: 20250402-tcp-ao-selfconnect-flake-e0aabc03c076 Best regards, -- Dmitry Safonov <0x7f454c46(a)gmail.com>

8 months, 1 week

2
1
0 0

[PATCH bpf-next 00/11] bpf: Mitigate Spectre v1 using barriers

by Luis Gerhorst

This improves the expressiveness of unprivileged BPF by inserting speculation barriers instead of rejecting the programs. The approach was previously presented at LPC'24 [1] and RAID'24 [2]. To mitigate the Spectre v1 (PHT) vulnerability, the kernel rejects potentially-dangerous unprivileged BPF programs as of commit 9183671af6db ("bpf: Fix leakage under speculation on mispredicted branches"). In [2], we have analyzed 364 object files from open source projects (Linux Samples and Selftests, BCC, Loxilb, Cilium, libbpf Examples, Parca, and Prevail) and found that this affects 31% to 54% of programs. To resolve this in the majority of cases this patchset adds a fall-back for mitigating Spectre v1 using speculation barriers. The kernel still optimistically attempts to verify all speculative paths but uses speculation barriers against v1 when unsafe behavior is detected. This allows for more programs to be accepted without disabling the BPF Spectre mitigations (e.g., by setting cpu_mitigations_off()). In [1] we have measured the overhead of this approach relative to having mitigations off and including the upstream Spectre v4 mitigations. For event tracing and stack-sampling profilers, we found that mitigations increase BPF program execution time by 0% to 62%. For the Loxilb network load balancer, we have measured a 14% slowdown in SCTP performance but no significant slowdown for TCP. This overhead only applies to programs that were previously rejected. I reran the expressiveness-evaluation with v6.14 and made sure the main results still match those from [1] and [2] (which used v6.5). Main design decisions are: * Do not use separate bytecode insns for v1 and v4 barriers. This simplifies the verifier significantly and has the only downside that performance on PowerPC is not as high as it could be. * Allow archs to still disable v1/v4 mitigations separately by setting bpf_jit_bypass_spec_v1/v4(). This has the benefit that archs can benefit from improved BPF expressiveness / performance if they are not vulnerable (e.g., ARM64 for v4 in the kernel). * Do not remove the empty BPF_NOSPEC implementation for backends for which it is unknown whether they are vulnerable to Spectre v1. [1] https://lpc.events/event/18/contributions/1954/ ("Mitigating Spectre-PHT using Speculation Barriers in Linux eBPF") [2] https://arxiv.org/pdf/2405.00078 ("VeriFence: Lightweight and Precise Spectre Defenses for Untrusted Linux Kernel Extensions") Changes: * RFC -> v1: - rebase to bpf-next-250313 - tests: mark expected successes/new errors - add bpt_jit_bypass_spec_v1/v4() to avoid #ifdef in bpf_bypass_spec_v1/v4() - ensure that nospec with v1-support is implemented for archs for which GCC supports speculation barriers, except for MIPS - arm64: emit speculation barrier - powerpc: change nospec to include v1 barrier - discuss potential security (archs that do not impl. BPF nospec) and performance (only PowerPC) regressions RFC: https://lore.kernel.org/bpf/20250224203619.594724-1-luis.gerhorst@fau.de/ Luis Gerhorst (11): bpf: Move insn if/else into do_check_insn() bpf: Return -EFAULT on misconfigurations bpf: Return -EFAULT on internal errors bpf, arm64, powerpc: Add bpf_jit_bypass_spec_v1/v4() bpf, arm64, powerpc: Change nospec to include v1 barrier bpf: Rename sanitize_stack_spill to nospec_result bpf: Fall back to nospec for Spectre v1 bpf: Allow nospec-protected var-offset stack access bpf: Return PTR_ERR from push_stack() bpf: Fall back to nospec for sanitization-failures bpf: Fall back to nospec for spec path verification arch/arm64/net/bpf_jit.h | 5 + arch/arm64/net/bpf_jit_comp.c | 28 +- arch/powerpc/net/bpf_jit_comp64.c | 79 +- include/linux/bpf.h | 11 +- include/linux/bpf_verifier.h | 3 +- include/linux/filter.h | 2 +- kernel/bpf/core.c | 32 +- kernel/bpf/verifier.c | 723 ++++++++++-------- .../selftests/bpf/progs/verifier_and.c | 3 +- .../selftests/bpf/progs/verifier_bounds.c | 35 +- .../bpf/progs/verifier_bounds_deduction.c | 43 +- .../selftests/bpf/progs/verifier_map_ptr.c | 12 +- .../selftests/bpf/progs/verifier_movsx.c | 6 +- .../selftests/bpf/progs/verifier_unpriv.c | 3 +- .../bpf/progs/verifier_value_ptr_arith.c | 50 +- .../selftests/bpf/verifier/dead_code.c | 3 +- tools/testing/selftests/bpf/verifier/jmp32.c | 33 +- tools/testing/selftests/bpf/verifier/jset.c | 10 +- 18 files changed, 630 insertions(+), 451 deletions(-) base-commit: 46d38f489ef02175dcff1e03a849c226eb0729a6 -- 2.48.1

8 months, 1 week

3
22
0 0

[PATCH v2 0/5] KVM: guest_memfd: support for uffd minor

by Nikita Kalyazin

This series is built on top of Fuad's v7 "mapping guest_memfd backed memory at the host" [1]. With James's KVM userfault [2], it is possible to handle stage-2 faults in guest_memfd in userspace. However, KVM itself also triggers faults in guest_memfd in some cases, for example: PV interfaces like kvmclock, PV EOI and page table walking code when fetching the MMIO instruction on x86. It was agreed in the guest_memfd upstream call on 23 Jan 2025 [3] that KVM would be accessing those pages via userspace page tables. In order for such faults to be handled in userspace, guest_memfd needs to support userfaultfd. Changes since v1 [4]: - James, Peter: implement a full minor trap instead of a hybrid missing/minor trap - James, Peter: to avoid shmem- and guest_memfd-specific code in the UFFDIO_CONTINUE implementation make it generic by calling vm_ops->fault() While generalising UFFDIO_CONTINUE implementation helped avoid guest_memfd-specific code in mm/userfaulfd, userfaultfd still needs access to KVM code to be able to verify the VMA type when handling UFFDIO_REGISTER_MODE_MINOR, so I used a similar approach to what Fuad did for now [5]. In v1, Peter was mentioning a potential for eliminating taking a folio lock [6]. I did not implement that, but according to my testing, the performance of shmem minor fault handling stayed the same after the migration to calling vm_ops->fault() (tested on an x86). Before: ./demand_paging_test -u MINOR -s shmem Random seed: 0x6b8b4567 Testing guest mode: PA-bits:ANY, VA-bits:48, 4K pages guest physical test memory: [0x3fffbffff000, 0x3ffffffff000) Finished creating vCPUs and starting uffd threads Started all vCPUs All vCPU threads joined Total guest execution time: 10.979277020s Per-vcpu demand paging rate: 23876.253375 pgs/sec/vcpu Overall demand paging rate: 23876.253375 pgs/sec After: ./demand_paging_test -u MINOR -s shmem Random seed: 0x6b8b4567 Testing guest mode: PA-bits:ANY, VA-bits:48, 4K pages guest physical test memory: [0x3fffbffff000, 0x3ffffffff000) Finished creating vCPUs and starting uffd threads Started all vCPUs All vCPU threads joined Total guest execution time: 10.978893504s Per-vcpu demand paging rate: 23877.087423 pgs/sec/vcpu Overall demand paging rate: 23877.087423 pgs/sec Nikita [1] https://lore.kernel.org/kvm/20250318161823.4005529-1-tabba@google.com/T/ [2] https://lore.kernel.org/kvm/20250109204929.1106563-1-jthoughton@google.com/… [3] https://docs.google.com/document/d/1M6766BzdY1Lhk7LiR5IqVR8B8mG3cr-cxTxOrAo… [4] https://lore.kernel.org/kvm/20250303133011.44095-1-kalyazin@amazon.com/T/ [5] https://lore.kernel.org/kvm/20250318161823.4005529-1-tabba@google.com/T/#Z2… [6] https://lore.kernel.org/kvm/20250303133011.44095-1-kalyazin@amazon.com/T/#m… Nikita Kalyazin (5): mm: userfaultfd: generic continue for non hugetlbfs KVM: guest_memfd: add kvm_gmem_vma_is_gmem mm: userfaultfd: allow to register continue for guest_memfd KVM: guest_memfd: add support for userfaultfd minor KVM: selftests: test userfaultfd minor for guest_memfd include/linux/mm_types.h | 3 + include/linux/userfaultfd_k.h | 13 ++- mm/hugetlb.c | 2 +- mm/shmem.c | 3 +- mm/userfaultfd.c | 25 +++-- .../testing/selftests/kvm/guest_memfd_test.c | 94 +++++++++++++++++++ virt/kvm/guest_memfd.c | 15 +++ virt/kvm/kvm_mm.h | 1 + 8 files changed, 146 insertions(+), 10 deletions(-) base-commit: 3cc51efc17a2c41a480eed36b31c1773936717e0 -- 2.47.1

8 months, 2 weeks

2
11
0 0

[PATCH v2] selftests: riscv: fix v_exec_initval_nolibc.c

by Ignacio Encinas

Vector registers are zero initialized by the kernel. Stop accepting "all ones" as a clean value. Note that this was not working as expected given that value == 0xff can be assumed to be always false by the compiler as value's range is [-128, 127]. Both GCC (-Wtype-limits) and clang (-Wtautological-constant-out-of-range-compare) warn about this. Reviewed-by: Charlie Jenkins <charlie(a)rivosinc.com> Tested-by: Charlie Jenkins <charlie(a)rivosinc.com> Signed-off-by: Ignacio Encinas <ignacio(a)iencinas.com> --- Changes in v2: Remove code that becomes useless now that the only "clean" value for vector registers is 0. - Link to v1: https://lore.kernel.org/r/20250305-fix-v_exec_initval_nolibc-v1-1-b87b60e43… --- tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c index 35c0812e32de0c82a54f84bd52c4272507121e35..4dde05e45a04122b566cedc36d20b072413b00e2 100644 --- a/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c +++ b/tools/testing/selftests/riscv/vector/v_exec_initval_nolibc.c @@ -6,7 +6,7 @@ * the values. To further ensure consistency, this file is compiled without * libc and without auto-vectorization. * - * To be "clean" all values must be either all ones or all zeroes. + * To be "clean" all values must be all zeroes. */ #define __stringify_1(x...) #x @@ -14,9 +14,8 @@ int main(int argc, char **argv) { - char prev_value = 0, value; + char value = 0; unsigned long vl; - int first = 1; if (argc > 2 && strcmp(argv[2], "x")) asm volatile ( @@ -44,14 +43,11 @@ int main(int argc, char **argv) "vsrl.vi " __stringify(register) ", " __stringify(register) ", 8\n\t" \ ".option pop\n\t" \ : "=r" (value)); \ - if (first) { \ - first = 0; \ - } else if (value != prev_value || !(value == 0x00 || value == 0xff)) { \ + if (value != 0x00) { \ printf("Register " __stringify(register) \ " values not clean! value: %u\n", value); \ exit(-1); \ } \ - prev_value = value; \ } \ }) --- base-commit: 03d38806a902b36bf364cae8de6f1183c0a35a67 change-id: 20250301-fix-v_exec_initval_nolibc-498d976c372d Best regards, -- Ignacio Encinas <ignacio(a)iencinas.com>

8 months, 2 weeks

4
3
0 0

[PATCH 00/10] cgroup/cpuset: Miscellaneous partition bug fixes and enhancements

by Waiman Long

This patch series fixes a number of bugs in the cpuset partition code as well as improvement in remote partition handling. The test_cpuset_prs.sh is also enhanced to allow more vigorous remote partition testing. Waiman Long (10): cgroup/cpuset: Fix race between newly created partition and dying one cgroup/cpuset: Fix incorrect isolated_cpus update in update_parent_effective_cpumask() cgroup/cpuset: Fix error handling in remote_partition_disable() cgroup/cpuset: Remove remote_partition_check() & make update_cpumasks_hier() handle remote partition cgroup/cpuset: Don't allow creation of local partition over a remote one cgroup/cpuset: Code cleanup and comment update cgroup/cpuset: Remove unneeded goto in sched_partition_write() and rename it selftest/cgroup: Update test_cpuset_prs.sh to use | as effective CPUs and state separator selftest/cgroup: Clean up and restructure test_cpuset_prs.sh selftest/cgroup: Add a remote partition transition test to test_cpuset_prs.sh include/linux/cgroup-defs.h | 1 + include/linux/cgroup.h | 2 +- kernel/cgroup/cgroup.c | 6 + kernel/cgroup/cpuset-internal.h | 1 + kernel/cgroup/cpuset.c | 401 +++++++----- .../selftests/cgroup/test_cpuset_prs.sh | 617 ++++++++++++------ 6 files changed, 649 insertions(+), 379 deletions(-) -- 2.48.1

8 months, 2 weeks

4
23
0 0

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