[缺陷描述]： bcc：test_histogram.py用例失败，报错Failed to attach BPF program b'kprobe__finish_task_switch' to kprobe b'finish_task_switch' 软件版本： # rpm -qa |grep bcc bcc-tools-0.27.0-1.an23.aarch64 bcc-0.27.0-1.an23.aarch64 python3-bcc-0.27.0-1.an23.noarch bcc-devel-0.27.0-1.an23.aarch64 失败日志如下： # python test_histogram.py cannot attach kprobe, probe entry may not exist E k_1 & k_2 = 0 0 size : count distribution 512 -> 1023 : 2 |************* | 1024 -> 2047 : 0 | | 2048 -> 4095 : 0 | | 4096 -> 8191 : 6 |****************************************| k_1 & k_2 = 16 0 size : count distribution 8 -> 15 : 1 |******************** | 16 -> 31 : 2 |****************************************| k_1 & k_2 = 32 0 size : count distribution 256 -> 511 : 1 |****************************************| k_1 & k_2 = 48 0 size : count distribution 256 -> 511 : 2 |*** | 512 -> 1023 : 0 | | 1024 -> 2047 : 0 | | 2048 -> 4095 : 0 | | 4096 -> 8191 : 2 |*** | 8192 -> 16383 : 0 | | 16384 -> 32767 : 21 |****************************************| k_1 & k_2 = 48 1 size : count distribution 128 -> 255 : 1 |****************************************| k_1 & k_2 = 64 0 size : count distribution 4096 -> 8191 : 2 |****************************************| k_1 & k_2 = 112 0 size : count distribution 512 -> 1023 : 4 |******************************** | 1024 -> 2047 : 0 | | 2048 -> 4095 : 5 |****************************************| ... ====================================================================== ERROR: test_chars (__main__.TestHistogram) ---------------------------------------------------------------------- Traceback (most recent call last): File "/root/bcc/bcc/bcc-0.27.0/tests/python/test_histogram.py", line 61, in test_chars b = BPF(text=b""" File "/usr/lib/python3.10/site-packages/bcc/__init__.py", line 487, in __init__ self._trace_autoload() File "/usr/lib/python3.10/site-packages/bcc/__init__.py", line 1456, in _trace_autoload self.attach_kprobe( File "/usr/lib/python3.10/site-packages/bcc/__init__.py", line 845, in attach_kprobe raise Exception("Failed to attach BPF program %s to kprobe %s" Exception: Failed to attach BPF program b'kprobe__finish_task_switch' to kprobe b'finish_task_switch', it's not traceable (either non-existing, inlined, or marked as "notrace") ---------------------------------------------------------------------- Ran 4 tests in 3.021s FAILED (errors=1) [复现概率]： 必现 [复现环境]： 内核： # uname -r 6.6.25-2_rc1.an23.x86_64 # cat /etc/os-release NAME="Anolis OS" VERSION="23" ID="anolis" VERSION_ID="23" PLATFORM_ID="platform:an23" PRETTY_NAME="Anolis OS 23" ANSI_COLOR="0;31" HOME_URL="https://openanolis.cn/" BUG_REPORT_URL="https://bugzilla.openanolis.cn/" CPU信息： # lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Address sizes: 52 bits physical, 57 bits virtual Byte Order: Little Endian CPU(s): 4 On-line CPU(s) list: 0-3 Vendor ID: GenuineIntel BIOS Vendor ID: Alibaba Cloud Model name: Intel(R) Xeon(R) Platinum 8475B BIOS Model name: pc-q35-df-2.1 CPU @ 0.0GHz BIOS CPU family: 1 CPU family: 6 Model: 143 Thread(s) per core: 2 Core(s) per socket: 2 Socket(s): 1 Stepping: 8 CPU(s) scaling MHz: 84% CPU max MHz: 3800.0000 CPU min MHz: 800.0000 BogoMIPS: 5400.00 Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtsc p lm constant_tsc rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq monitor ssse3 fma cx16 pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch cpuid_fault ibrs_enhanced fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm avx512f avx512dq rdseed adx smap avx512ifma clflushopt clwb avx512c d sha_ni avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves avx_vnni avx512_bf16 wbnoinvd ida arat hwp hwp_notify hwp_act_window h wp_epp hwp_pkg_req avx512vbmi umip pku ospke waitpkg avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg avx512_vpopcntd q rdpid bus_lock_detect cldemote movdiri movdir64b enqcmd fsrm md_clear serialize tsxldtrk amx_bf16 avx512_fp16 amx_tile amx_int 8 arch_capabilities Virtualization features: Hypervisor vendor: KVM Virtualization type: full Caches (sum of all): L1d: 96 KiB (2 instances) L1i: 64 KiB (2 instances) L2: 4 MiB (2 instances) L3: 97.5 MiB (1 instance) NUMA: NUMA node(s): 1 NUMA node0 CPU(s): 0-3 Vulnerabilities: Gather data sampling: Not affected Itlb multihit: Not affected L1tf: Not affected Mds: Not affected Meltdown: Not affected Mmio stale data: Unknown: No mitigations Reg file data sampling: Not affected Retbleed: Not affected Spec rstack overflow: Not affected Spec store bypass: Vulnerable Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization Spectre v2: Mitigation; Enhanced / Automatic IBRS, RSB filling, PBRSB-eIBRS SW sequence Srbds: Not affected Tsx async abort: Not affected 内存信息： # free -h total used free shared buff/cache available Mem: 15Gi 585Mi 6.9Gi 364Mi 7.6Gi 13Gi Swap: 0B 0B 0B [复现步骤]： yum install bcc-tools yum-utils rpm-build python3-pyroute2.noarch git clone https://gitee.com/src-anolis-os/bcc.git --branch a23 cd bcc yum-builddep -y bcc.spec rpmbuild -D "_topdir $(pwd)" \ -D "_sourcedir $(pwd)" \ -D "_builddir $(pwd)" \ -bp bcc.spec cd bcc-0.27.0/tests/python python test_clang.py [预期结果]： 用例执行成功 [实际结果]： 用例执行失败
cat /sys/kernel/debug/tracing/available_filter_functions | grep finish_task_switch finish_task_switch.isra.0 可用trace的函数做了修改，请确认该修改是否为版本规划要求，如果函数修改对应的kernel selftest的用例需要适配
finish_task_switch 会被GCC10以上版本优化为 finish_task_switch.isra.0，其中 isra 是 inter-procedural scalar replacement of aggregates 的缩写。 如果用户想trace finish_task_switch 函数，有多种方法： 1. 让 finish_task_switch 不被 GCC 优化，方法有删掉 finish_task_switch 前面的 static 或者修改为 asmlinkage __visible 2. 直接trace finish_task_switch.isra.0，这个在bcc另外的example里有实现，比如./bcc/examples/tracing/task_switch.py 里 b = BPF(src_file="task_switch.c") b.attach_kprobe(event_re="^finish_task_switch$|^finish_task_switch\.isra\.\d$", fn_name="count_sched") 实测可以成功 trace 本例 test_histogram.py 里的实现: int kprobe__finish_task_switch 无法修改为 finish_task_switch.isra.0。 本bugzilla所示只是个例子，用户可以自行通过 trace finish_task_switch.isra.0 的方法实现功能，非内核问题，上游bcc本例无修改，置为 wont fix
如上述开发定位所说，非内核问题，本问题单关闭。
在6.6.71-3_rc1.al8.aarch64内核上也有同样的问题，在此做个纪录