https://sourceware.org/bugzilla/show_bug.cgi?id=27925
--- Comment #4 from William Cohen <wcohen at redhat dot com> --- The patch was a first attempt to get something that addresses the issue. Thanks for pointing out where it needs improvements. Don't have a good way to test the issue in user-space so far as the 64-bit risc-v gcc environment seems the expect to have have floating point support. One way to test might to use perf to set up a probe point (https://www.brendangregg.com/perf.html), but I don't know if perf is using elfutils to get the return value location. Based on the pfault.stp example would have something like: sudo perf probe handle_mm_fault%return $retval sudo perf record -e probe:handle_mm_fault__return -aR sleep 1 sudo perf report sudo perf probe --del="handle_mm_fault__return" This issue occurs when using systemtap on the RISC-V linux kernel which doesn't link against the normal glibc runtime and takes steps to ensure that the floating point hardware is not used. Below is a example gcc commandline from a native build (note the -mabi=lp64 -march=rv64imac options): gcc -Wp,-MMD,arch/riscv/kernel/probes/.kprobes.o.d -nostdinc -isystem /usr/lib/gcc/riscv64-redhat-linux/10/include -I./arch/riscv/include -I./arch/riscv/include/generated -I./include -I./arch/riscv/include/uapi -I./arch/riscv/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -DCC_USING_PATCHABLE_FUNCTION_ENTRY -fmacro-prefix-map=./= -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE -Werror=implicit-function-declaration -Werror=implicit-int -Werror=return-type -Wno-format-security -std=gnu89 -mabi=lp64 -march=rv64imac -mno-save-restore -DCONFIG_PAGE_OFFSET=0xffffffe000000000 -mcmodel=medany -fno-omit-frame-pointer -mstrict-align -fno-delete-null-pointer-checks -Wno-frame-address -Wno-format-truncation -Wno-format-overflow -Wno-address-of-packed-member -O2 -fno-allow-store-data-races -Wframe-larger-than=2048 -fno-stack-protector -Wimplicit-fallthrough=5 -Wno-unused-but-set-variable -Wno-unused-const-variable -fno-omit-frame-pointer -fno-optimize-sibling-calls -fno-stack-clash-protection -g -fpatchable-function-entry=8 -Wdeclaration-after-statement -Wvla -Wno-pointer-sign -Wno-stringop-truncation -Wno-zero-length-bounds -Wno-array-bounds -Wno-stringop-overflow -Wno-restrict -Wno-maybe-uninitialized -fno-strict-overflow -fno-stack-check -fconserve-stack -Werror=date-time -Werror=incompatible-pointer-types -Werror=designated-init -Wno-packed-not-aligned -DKBUILD_MODFILE='"arch/riscv/kernel/probes/kprobes"' -DKBUILD_BASENAME='"kprobes"' -DKBUILD_MODNAME='"kprobes"' -D__KBUILD_MODNAME=kmod_kprobes -c -o arch/riscv/kernel/probes/kprobes.o arch/riscv/kernel/probes/kprobes.c -- You are receiving this mail because: You are on the CC list for the bug.
