January 2024 - Linux-kselftest-mirror

[PATCH AUTOSEL 5.4 03/31] selftests/bpf: Fix pyperf180 compilation failure with clang18

by Sasha Levin

From: Yonghong Song <yonghong.song(a)linux.dev> [ Upstream commit 100888fb6d8a185866b1520031ee7e3182b173de ] With latest clang18 (main branch of llvm-project repo), when building bpf selftests, [~/work/bpf-next (master)]$ make -C tools/testing/selftests/bpf LLVM=1 -j The following compilation error happens: fatal error: error in backend: Branch target out of insn range ... Stack dump: 0. Program arguments: clang -g -Wall -Werror -D__TARGET_ARCH_x86 -mlittle-endian -I/home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/include -I/home/yhs/work/bpf-next/tools/testing/selftests/bpf -I/home/yhs/work/bpf-next/tools/include/uapi -I/home/yhs/work/bpf-next/tools/testing/selftests/usr/include -idirafter /home/yhs/work/llvm-project/llvm/build.18/install/lib/clang/18/include -idirafter /usr/local/include -idirafter /usr/include -Wno-compare-distinct-pointer-types -DENABLE_ATOMICS_TESTS -O2 --target=bpf -c progs/pyperf180.c -mcpu=v3 -o /home/yhs/work/bpf-next/tools/testing/selftests/bpf/pyperf180.bpf.o 1. <eof> parser at end of file 2. Code generation ... The compilation failure only happens to cpu=v2 and cpu=v3. cpu=v4 is okay since cpu=v4 supports 32-bit branch target offset. The above failure is due to upstream llvm patch [1] where some inlining behavior are changed in clang18. To workaround the issue, previously all 180 loop iterations are fully unrolled. The bpf macro __BPF_CPU_VERSION__ (implemented in clang18 recently) is used to avoid unrolling changes if cpu=v4. If __BPF_CPU_VERSION__ is not available and the compiler is clang18, the unrollng amount is unconditionally reduced. [1] https://github.com/llvm/llvm-project/commit/1a2e77cf9e11dbf56b5720c607313a5… Signed-off-by: Yonghong Song <yonghong.song(a)linux.dev> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Tested-by: Alan Maguire <alan.maguire(a)oracle.com> Link: https://lore.kernel.org/bpf/20231110193644.3130906-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/progs/pyperf180.c | 22 +++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/pyperf180.c b/tools/testing/selftests/bpf/progs/pyperf180.c index c39f559d3100..42c4a8b62e36 100644 --- a/tools/testing/selftests/bpf/progs/pyperf180.c +++ b/tools/testing/selftests/bpf/progs/pyperf180.c @@ -1,4 +1,26 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2019 Facebook #define STACK_MAX_LEN 180 + +/* llvm upstream commit at clang18 + * https://github.com/llvm/llvm-project/commit/1a2e77cf9e11dbf56b5720c607313a5… + * changed inlining behavior and caused compilation failure as some branch + * target distance exceeded 16bit representation which is the maximum for + * cpu v1/v2/v3. Macro __BPF_CPU_VERSION__ is later implemented in clang18 + * to specify which cpu version is used for compilation. So a smaller + * unroll_count can be set if __BPF_CPU_VERSION__ is less than 4, which + * reduced some branch target distances and resolved the compilation failure. + * + * To capture the case where a developer/ci uses clang18 but the corresponding + * repo checkpoint does not have __BPF_CPU_VERSION__, a smaller unroll_count + * will be set as well to prevent potential compilation failures. + */ +#ifdef __BPF_CPU_VERSION__ +#if __BPF_CPU_VERSION__ < 4 +#define UNROLL_COUNT 90 +#endif +#elif __clang_major__ == 18 +#define UNROLL_COUNT 90 +#endif + #include "pyperf.h" -- 2.43.0

11 months, 2 weeks

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[PATCH AUTOSEL 5.4 02/31] selftests/bpf: satisfy compiler by having explicit return in btf test

by Sasha Levin

From: Andrii Nakryiko <andrii(a)kernel.org> [ Upstream commit f4c7e887324f5776eef6e6e47a90e0ac8058a7a8 ] Some compilers complain about get_pprint_mapv_size() not returning value in some code paths. Fix with explicit return. Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Link: https://lore.kernel.org/r/20231102033759.2541186-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/test_btf.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c index f641eb292a88..a821ff121e03 100644 --- a/tools/testing/selftests/bpf/test_btf.c +++ b/tools/testing/selftests/bpf/test_btf.c @@ -4663,6 +4663,7 @@ static size_t get_pprint_mapv_size(enum pprint_mapv_kind_t mapv_kind) #endif assert(0); + return 0; } static void set_pprint_mapv(enum pprint_mapv_kind_t mapv_kind, -- 2.43.0

11 months, 2 weeks

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[PATCH AUTOSEL 5.10 03/44] selftests/bpf: Fix pyperf180 compilation failure with clang18

by Sasha Levin

From: Yonghong Song <yonghong.song(a)linux.dev> [ Upstream commit 100888fb6d8a185866b1520031ee7e3182b173de ] With latest clang18 (main branch of llvm-project repo), when building bpf selftests, [~/work/bpf-next (master)]$ make -C tools/testing/selftests/bpf LLVM=1 -j The following compilation error happens: fatal error: error in backend: Branch target out of insn range ... Stack dump: 0. Program arguments: clang -g -Wall -Werror -D__TARGET_ARCH_x86 -mlittle-endian -I/home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/include -I/home/yhs/work/bpf-next/tools/testing/selftests/bpf -I/home/yhs/work/bpf-next/tools/include/uapi -I/home/yhs/work/bpf-next/tools/testing/selftests/usr/include -idirafter /home/yhs/work/llvm-project/llvm/build.18/install/lib/clang/18/include -idirafter /usr/local/include -idirafter /usr/include -Wno-compare-distinct-pointer-types -DENABLE_ATOMICS_TESTS -O2 --target=bpf -c progs/pyperf180.c -mcpu=v3 -o /home/yhs/work/bpf-next/tools/testing/selftests/bpf/pyperf180.bpf.o 1. <eof> parser at end of file 2. Code generation ... The compilation failure only happens to cpu=v2 and cpu=v3. cpu=v4 is okay since cpu=v4 supports 32-bit branch target offset. The above failure is due to upstream llvm patch [1] where some inlining behavior are changed in clang18. To workaround the issue, previously all 180 loop iterations are fully unrolled. The bpf macro __BPF_CPU_VERSION__ (implemented in clang18 recently) is used to avoid unrolling changes if cpu=v4. If __BPF_CPU_VERSION__ is not available and the compiler is clang18, the unrollng amount is unconditionally reduced. [1] https://github.com/llvm/llvm-project/commit/1a2e77cf9e11dbf56b5720c607313a5… Signed-off-by: Yonghong Song <yonghong.song(a)linux.dev> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Tested-by: Alan Maguire <alan.maguire(a)oracle.com> Link: https://lore.kernel.org/bpf/20231110193644.3130906-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/progs/pyperf180.c | 22 +++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/pyperf180.c b/tools/testing/selftests/bpf/progs/pyperf180.c index c39f559d3100..42c4a8b62e36 100644 --- a/tools/testing/selftests/bpf/progs/pyperf180.c +++ b/tools/testing/selftests/bpf/progs/pyperf180.c @@ -1,4 +1,26 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2019 Facebook #define STACK_MAX_LEN 180 + +/* llvm upstream commit at clang18 + * https://github.com/llvm/llvm-project/commit/1a2e77cf9e11dbf56b5720c607313a5… + * changed inlining behavior and caused compilation failure as some branch + * target distance exceeded 16bit representation which is the maximum for + * cpu v1/v2/v3. Macro __BPF_CPU_VERSION__ is later implemented in clang18 + * to specify which cpu version is used for compilation. So a smaller + * unroll_count can be set if __BPF_CPU_VERSION__ is less than 4, which + * reduced some branch target distances and resolved the compilation failure. + * + * To capture the case where a developer/ci uses clang18 but the corresponding + * repo checkpoint does not have __BPF_CPU_VERSION__, a smaller unroll_count + * will be set as well to prevent potential compilation failures. + */ +#ifdef __BPF_CPU_VERSION__ +#if __BPF_CPU_VERSION__ < 4 +#define UNROLL_COUNT 90 +#endif +#elif __clang_major__ == 18 +#define UNROLL_COUNT 90 +#endif + #include "pyperf.h" -- 2.43.0

11 months, 2 weeks

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[PATCH AUTOSEL 5.10 02/44] selftests/bpf: satisfy compiler by having explicit return in btf test

by Sasha Levin

From: Andrii Nakryiko <andrii(a)kernel.org> [ Upstream commit f4c7e887324f5776eef6e6e47a90e0ac8058a7a8 ] Some compilers complain about get_pprint_mapv_size() not returning value in some code paths. Fix with explicit return. Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Link: https://lore.kernel.org/r/20231102033759.2541186-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/prog_tests/btf.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c index 28d22265b825..cbdc2839904e 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf.c +++ b/tools/testing/selftests/bpf/prog_tests/btf.c @@ -4611,6 +4611,7 @@ static size_t get_pprint_mapv_size(enum pprint_mapv_kind_t mapv_kind) #endif assert(0); + return 0; } static void set_pprint_mapv(enum pprint_mapv_kind_t mapv_kind, -- 2.43.0

11 months, 2 weeks

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[PATCH AUTOSEL 5.15 04/47] selftests/bpf: Fix issues in setup_classid_environment()

by Sasha Levin

From: Yafang Shao <laoar.shao(a)gmail.com> [ Upstream commit 4849775587844e44d215289c425bcd70f315efe7 ] If the net_cls subsystem is already mounted, attempting to mount it again in setup_classid_environment() will result in a failure with the error code EBUSY. Despite this, tmpfs will have been successfully mounted at /sys/fs/cgroup/net_cls. Consequently, the /sys/fs/cgroup/net_cls directory will be empty, causing subsequent setup operations to fail. Here's an error log excerpt illustrating the issue when net_cls has already been mounted at /sys/fs/cgroup/net_cls prior to running setup_classid_environment(): - Before that change $ tools/testing/selftests/bpf/test_progs --name=cgroup_v1v2 test_cgroup_v1v2:PASS:server_fd 0 nsec test_cgroup_v1v2:PASS:client_fd 0 nsec test_cgroup_v1v2:PASS:cgroup_fd 0 nsec test_cgroup_v1v2:PASS:server_fd 0 nsec run_test:PASS:skel_open 0 nsec run_test:PASS:prog_attach 0 nsec test_cgroup_v1v2:PASS:cgroup-v2-only 0 nsec (cgroup_helpers.c:248: errno: No such file or directory) Opening Cgroup Procs: /sys/fs/cgroup/net_cls/cgroup.procs (cgroup_helpers.c:540: errno: No such file or directory) Opening cgroup classid: /sys/fs/cgroup/net_cls/cgroup-test-work-dir/net_cls.classid run_test:PASS:skel_open 0 nsec run_test:PASS:prog_attach 0 nsec (cgroup_helpers.c:248: errno: No such file or directory) Opening Cgroup Procs: /sys/fs/cgroup/net_cls/cgroup-test-work-dir/cgroup.procs run_test:FAIL:join_classid unexpected error: 1 (errno 2) test_cgroup_v1v2:FAIL:cgroup-v1v2 unexpected error: -1 (errno 2) (cgroup_helpers.c:248: errno: No such file or directory) Opening Cgroup Procs: /sys/fs/cgroup/net_cls/cgroup.procs #44 cgroup_v1v2:FAIL Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED - After that change $ tools/testing/selftests/bpf/test_progs --name=cgroup_v1v2 #44 cgroup_v1v2:OK Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Yafang Shao <laoar.shao(a)gmail.com> Link: https://lore.kernel.org/r/20231111090034.4248-3-laoar.shao@gmail.com Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/cgroup_helpers.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/selftests/bpf/cgroup_helpers.c index f3daa44a8266..f63c7ee3d798 100644 --- a/tools/testing/selftests/bpf/cgroup_helpers.c +++ b/tools/testing/selftests/bpf/cgroup_helpers.c @@ -348,10 +348,20 @@ int setup_classid_environment(void) return 1; } - if (mount("net_cls", NETCLS_MOUNT_PATH, "cgroup", 0, "net_cls") && - errno != EBUSY) { - log_err("mount cgroup net_cls"); - return 1; + if (mount("net_cls", NETCLS_MOUNT_PATH, "cgroup", 0, "net_cls")) { + if (errno != EBUSY) { + log_err("mount cgroup net_cls"); + return 1; + } + + if (rmdir(NETCLS_MOUNT_PATH)) { + log_err("rmdir cgroup net_cls"); + return 1; + } + if (umount(CGROUP_MOUNT_DFLT)) { + log_err("umount cgroup base"); + return 1; + } } cleanup_classid_environment(); -- 2.43.0

11 months, 2 weeks

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[PATCH AUTOSEL 5.15 03/47] selftests/bpf: Fix pyperf180 compilation failure with clang18

by Sasha Levin

From: Yonghong Song <yonghong.song(a)linux.dev> [ Upstream commit 100888fb6d8a185866b1520031ee7e3182b173de ] With latest clang18 (main branch of llvm-project repo), when building bpf selftests, [~/work/bpf-next (master)]$ make -C tools/testing/selftests/bpf LLVM=1 -j The following compilation error happens: fatal error: error in backend: Branch target out of insn range ... Stack dump: 0. Program arguments: clang -g -Wall -Werror -D__TARGET_ARCH_x86 -mlittle-endian -I/home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/include -I/home/yhs/work/bpf-next/tools/testing/selftests/bpf -I/home/yhs/work/bpf-next/tools/include/uapi -I/home/yhs/work/bpf-next/tools/testing/selftests/usr/include -idirafter /home/yhs/work/llvm-project/llvm/build.18/install/lib/clang/18/include -idirafter /usr/local/include -idirafter /usr/include -Wno-compare-distinct-pointer-types -DENABLE_ATOMICS_TESTS -O2 --target=bpf -c progs/pyperf180.c -mcpu=v3 -o /home/yhs/work/bpf-next/tools/testing/selftests/bpf/pyperf180.bpf.o 1. <eof> parser at end of file 2. Code generation ... The compilation failure only happens to cpu=v2 and cpu=v3. cpu=v4 is okay since cpu=v4 supports 32-bit branch target offset. The above failure is due to upstream llvm patch [1] where some inlining behavior are changed in clang18. To workaround the issue, previously all 180 loop iterations are fully unrolled. The bpf macro __BPF_CPU_VERSION__ (implemented in clang18 recently) is used to avoid unrolling changes if cpu=v4. If __BPF_CPU_VERSION__ is not available and the compiler is clang18, the unrollng amount is unconditionally reduced. [1] https://github.com/llvm/llvm-project/commit/1a2e77cf9e11dbf56b5720c607313a5… Signed-off-by: Yonghong Song <yonghong.song(a)linux.dev> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Tested-by: Alan Maguire <alan.maguire(a)oracle.com> Link: https://lore.kernel.org/bpf/20231110193644.3130906-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/progs/pyperf180.c | 22 +++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/pyperf180.c b/tools/testing/selftests/bpf/progs/pyperf180.c index c39f559d3100..42c4a8b62e36 100644 --- a/tools/testing/selftests/bpf/progs/pyperf180.c +++ b/tools/testing/selftests/bpf/progs/pyperf180.c @@ -1,4 +1,26 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2019 Facebook #define STACK_MAX_LEN 180 + +/* llvm upstream commit at clang18 + * https://github.com/llvm/llvm-project/commit/1a2e77cf9e11dbf56b5720c607313a5… + * changed inlining behavior and caused compilation failure as some branch + * target distance exceeded 16bit representation which is the maximum for + * cpu v1/v2/v3. Macro __BPF_CPU_VERSION__ is later implemented in clang18 + * to specify which cpu version is used for compilation. So a smaller + * unroll_count can be set if __BPF_CPU_VERSION__ is less than 4, which + * reduced some branch target distances and resolved the compilation failure. + * + * To capture the case where a developer/ci uses clang18 but the corresponding + * repo checkpoint does not have __BPF_CPU_VERSION__, a smaller unroll_count + * will be set as well to prevent potential compilation failures. + */ +#ifdef __BPF_CPU_VERSION__ +#if __BPF_CPU_VERSION__ < 4 +#define UNROLL_COUNT 90 +#endif +#elif __clang_major__ == 18 +#define UNROLL_COUNT 90 +#endif + #include "pyperf.h" -- 2.43.0

11 months, 2 weeks

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[PATCH AUTOSEL 5.15 02/47] selftests/bpf: satisfy compiler by having explicit return in btf test

by Sasha Levin

From: Andrii Nakryiko <andrii(a)kernel.org> [ Upstream commit f4c7e887324f5776eef6e6e47a90e0ac8058a7a8 ] Some compilers complain about get_pprint_mapv_size() not returning value in some code paths. Fix with explicit return. Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Link: https://lore.kernel.org/r/20231102033759.2541186-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/prog_tests/btf.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c index 2a04dbec510d..92080f64b5cc 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf.c +++ b/tools/testing/selftests/bpf/prog_tests/btf.c @@ -4766,6 +4766,7 @@ static size_t get_pprint_mapv_size(enum pprint_mapv_kind_t mapv_kind) #endif assert(0); + return 0; } static void set_pprint_mapv(enum pprint_mapv_kind_t mapv_kind, -- 2.43.0

11 months, 2 weeks

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[PATCH AUTOSEL 6.1 05/68] selftests/bpf: Fix issues in setup_classid_environment()

by Sasha Levin

From: Yafang Shao <laoar.shao(a)gmail.com> [ Upstream commit 4849775587844e44d215289c425bcd70f315efe7 ] If the net_cls subsystem is already mounted, attempting to mount it again in setup_classid_environment() will result in a failure with the error code EBUSY. Despite this, tmpfs will have been successfully mounted at /sys/fs/cgroup/net_cls. Consequently, the /sys/fs/cgroup/net_cls directory will be empty, causing subsequent setup operations to fail. Here's an error log excerpt illustrating the issue when net_cls has already been mounted at /sys/fs/cgroup/net_cls prior to running setup_classid_environment(): - Before that change $ tools/testing/selftests/bpf/test_progs --name=cgroup_v1v2 test_cgroup_v1v2:PASS:server_fd 0 nsec test_cgroup_v1v2:PASS:client_fd 0 nsec test_cgroup_v1v2:PASS:cgroup_fd 0 nsec test_cgroup_v1v2:PASS:server_fd 0 nsec run_test:PASS:skel_open 0 nsec run_test:PASS:prog_attach 0 nsec test_cgroup_v1v2:PASS:cgroup-v2-only 0 nsec (cgroup_helpers.c:248: errno: No such file or directory) Opening Cgroup Procs: /sys/fs/cgroup/net_cls/cgroup.procs (cgroup_helpers.c:540: errno: No such file or directory) Opening cgroup classid: /sys/fs/cgroup/net_cls/cgroup-test-work-dir/net_cls.classid run_test:PASS:skel_open 0 nsec run_test:PASS:prog_attach 0 nsec (cgroup_helpers.c:248: errno: No such file or directory) Opening Cgroup Procs: /sys/fs/cgroup/net_cls/cgroup-test-work-dir/cgroup.procs run_test:FAIL:join_classid unexpected error: 1 (errno 2) test_cgroup_v1v2:FAIL:cgroup-v1v2 unexpected error: -1 (errno 2) (cgroup_helpers.c:248: errno: No such file or directory) Opening Cgroup Procs: /sys/fs/cgroup/net_cls/cgroup.procs #44 cgroup_v1v2:FAIL Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED - After that change $ tools/testing/selftests/bpf/test_progs --name=cgroup_v1v2 #44 cgroup_v1v2:OK Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Yafang Shao <laoar.shao(a)gmail.com> Link: https://lore.kernel.org/r/20231111090034.4248-3-laoar.shao@gmail.com Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/cgroup_helpers.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/selftests/bpf/cgroup_helpers.c index e914cc45b766..6f00bee917a0 100644 --- a/tools/testing/selftests/bpf/cgroup_helpers.c +++ b/tools/testing/selftests/bpf/cgroup_helpers.c @@ -467,10 +467,20 @@ int setup_classid_environment(void) return 1; } - if (mount("net_cls", NETCLS_MOUNT_PATH, "cgroup", 0, "net_cls") && - errno != EBUSY) { - log_err("mount cgroup net_cls"); - return 1; + if (mount("net_cls", NETCLS_MOUNT_PATH, "cgroup", 0, "net_cls")) { + if (errno != EBUSY) { + log_err("mount cgroup net_cls"); + return 1; + } + + if (rmdir(NETCLS_MOUNT_PATH)) { + log_err("rmdir cgroup net_cls"); + return 1; + } + if (umount(CGROUP_MOUNT_DFLT)) { + log_err("umount cgroup base"); + return 1; + } } cleanup_classid_environment(); -- 2.43.0

11 months, 2 weeks

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[PATCH AUTOSEL 6.1 03/68] selftests/bpf: Fix pyperf180 compilation failure with clang18

by Sasha Levin

From: Yonghong Song <yonghong.song(a)linux.dev> [ Upstream commit 100888fb6d8a185866b1520031ee7e3182b173de ] With latest clang18 (main branch of llvm-project repo), when building bpf selftests, [~/work/bpf-next (master)]$ make -C tools/testing/selftests/bpf LLVM=1 -j The following compilation error happens: fatal error: error in backend: Branch target out of insn range ... Stack dump: 0. Program arguments: clang -g -Wall -Werror -D__TARGET_ARCH_x86 -mlittle-endian -I/home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/include -I/home/yhs/work/bpf-next/tools/testing/selftests/bpf -I/home/yhs/work/bpf-next/tools/include/uapi -I/home/yhs/work/bpf-next/tools/testing/selftests/usr/include -idirafter /home/yhs/work/llvm-project/llvm/build.18/install/lib/clang/18/include -idirafter /usr/local/include -idirafter /usr/include -Wno-compare-distinct-pointer-types -DENABLE_ATOMICS_TESTS -O2 --target=bpf -c progs/pyperf180.c -mcpu=v3 -o /home/yhs/work/bpf-next/tools/testing/selftests/bpf/pyperf180.bpf.o 1. <eof> parser at end of file 2. Code generation ... The compilation failure only happens to cpu=v2 and cpu=v3. cpu=v4 is okay since cpu=v4 supports 32-bit branch target offset. The above failure is due to upstream llvm patch [1] where some inlining behavior are changed in clang18. To workaround the issue, previously all 180 loop iterations are fully unrolled. The bpf macro __BPF_CPU_VERSION__ (implemented in clang18 recently) is used to avoid unrolling changes if cpu=v4. If __BPF_CPU_VERSION__ is not available and the compiler is clang18, the unrollng amount is unconditionally reduced. [1] https://github.com/llvm/llvm-project/commit/1a2e77cf9e11dbf56b5720c607313a5… Signed-off-by: Yonghong Song <yonghong.song(a)linux.dev> Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Tested-by: Alan Maguire <alan.maguire(a)oracle.com> Link: https://lore.kernel.org/bpf/20231110193644.3130906-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/progs/pyperf180.c | 22 +++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/pyperf180.c b/tools/testing/selftests/bpf/progs/pyperf180.c index c39f559d3100..42c4a8b62e36 100644 --- a/tools/testing/selftests/bpf/progs/pyperf180.c +++ b/tools/testing/selftests/bpf/progs/pyperf180.c @@ -1,4 +1,26 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2019 Facebook #define STACK_MAX_LEN 180 + +/* llvm upstream commit at clang18 + * https://github.com/llvm/llvm-project/commit/1a2e77cf9e11dbf56b5720c607313a5… + * changed inlining behavior and caused compilation failure as some branch + * target distance exceeded 16bit representation which is the maximum for + * cpu v1/v2/v3. Macro __BPF_CPU_VERSION__ is later implemented in clang18 + * to specify which cpu version is used for compilation. So a smaller + * unroll_count can be set if __BPF_CPU_VERSION__ is less than 4, which + * reduced some branch target distances and resolved the compilation failure. + * + * To capture the case where a developer/ci uses clang18 but the corresponding + * repo checkpoint does not have __BPF_CPU_VERSION__, a smaller unroll_count + * will be set as well to prevent potential compilation failures. + */ +#ifdef __BPF_CPU_VERSION__ +#if __BPF_CPU_VERSION__ < 4 +#define UNROLL_COUNT 90 +#endif +#elif __clang_major__ == 18 +#define UNROLL_COUNT 90 +#endif + #include "pyperf.h" -- 2.43.0

11 months, 2 weeks

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[PATCH AUTOSEL 6.1 02/68] selftests/bpf: satisfy compiler by having explicit return in btf test

by Sasha Levin

From: Andrii Nakryiko <andrii(a)kernel.org> [ Upstream commit f4c7e887324f5776eef6e6e47a90e0ac8058a7a8 ] Some compilers complain about get_pprint_mapv_size() not returning value in some code paths. Fix with explicit return. Signed-off-by: Andrii Nakryiko <andrii(a)kernel.org> Link: https://lore.kernel.org/r/20231102033759.2541186-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/prog_tests/btf.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c index d711f4bea98e..47cb753ef1e3 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf.c +++ b/tools/testing/selftests/bpf/prog_tests/btf.c @@ -5211,6 +5211,7 @@ static size_t get_pprint_mapv_size(enum pprint_mapv_kind_t mapv_kind) #endif assert(0); + return 0; } static void set_pprint_mapv(enum pprint_mapv_kind_t mapv_kind, -- 2.43.0

11 months, 2 weeks

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