On Fri, Jun 21, 2024 at 12:24:03AM +0530, Naveen N Rao wrote: > This is v3 of the patches posted here: > http://lkml.kernel.org/r/cover.1718008093.git.naveen@xxxxxxxxxx > > Since v2, I have addressed review comments from Steven and Masahiro > along with a few fixes. Patches 7-11 are new in this series and add > support for ftrace direct and bpf trampolines. > > This series depends on the patch series from Benjamin Gray adding > support for patch_ulong(): > http://lkml.kernel.org/r/20240515024445.236364-1-bgray@xxxxxxxxxxxxx > > > - Naveen Hello Naveen, I've noticed an issue with `kstack()` in bpftrace [1] when using `kfunc` compared to `kprobe`. Despite trying all three modes specified in the documentation (bpftrace, perf, or raw), the stack isn't unwinding properly with `kfunc`. [1] https://github.com/bpftrace/bpftrace/blob/master/man/adoc/bpftrace.adoc#kstack for mode in modes; do run bpftrace with kfunc disable cpu kill bpftrace run bpftrace with kprobe enable cpu kill bpftrace # ./kprobe_vs_kfunc.sh + bpftrace -e 'kfunc:vmlinux:build_sched_domains {@[kstack(bpftrace), comm, tid]=count();}' Attaching 1 probe... + chcpu -d 2-3 CPU 2 disabled CPU 3 disabled + kill 35214 @[ bpf_prog_cfd8d6c8bb4898ce+972 , cpuhp/2, 33]: 1 @[ bpf_prog_cfd8d6c8bb4898ce+972 , cpuhp/3, 38]: 1 + bpftrace -e 'kprobe:build_sched_domains {@[kstack(bpftrace), comm, tid]=count();}' Attaching 1 probe... + chcpu -e 2-3 CPU 2 enabled CPU 3 enabled + kill 35221 @[ 0x80000007642bdfb4 partition_sched_domains_locked+1304 rebuild_sched_domains_locked+216 cpuset_handle_hotplug+1148 sched_cpu_activate+664 cpuhp_invoke_callback+480 cpuhp_thread_fun+244 smpboot_thread_fn+460 kthread+308 start_kernel_thread+20 , cpuhp/3, 38]: 1 @[ 0x80000007524b34a4 partition_sched_domains_locked+1304 rebuild_sched_domains_locked+216 cpuset_handle_hotplug+1148 sched_cpu_activate+664 cpuhp_invoke_callback+480 cpuhp_thread_fun+244 smpboot_thread_fn+460 kthread+308 start_kernel_thread+20 , cpuhp/2, 33]: 1 + bpftrace -e 'kfunc:vmlinux:build_sched_domains {@[kstack(perf), comm, tid]=count();}' Attaching 1 probe... + chcpu -d 2-3 CPU 2 disabled CPU 3 disabled + kill 35229 @[ c008000003433454 bpf_prog_cfd8d6c8bb4898ce+960 , cpuhp/3, 38]: 1 @[ c008000003433454 bpf_prog_cfd8d6c8bb4898ce+960 , cpuhp/2, 33]: 1 + bpftrace -e 'kprobe:build_sched_domains {@[kstack(perf), comm, tid]=count();}' Attaching 1 probe... + chcpu -e 2-3 CPU 2 enabled CPU 3 enabled + kill 35235 @[ 80000007524b379c 0x80000007524b379c c000000000206268 partition_sched_domains_locked+1304 c0000000002cbf08 rebuild_sched_domains_locked+216 c0000000002cfd5c cpuset_handle_hotplug+1148 c0000000001b3178 sched_cpu_activate+664 c000000000156fc0 cpuhp_invoke_callback+480 c000000000157974 cpuhp_thread_fun+244 c00000000019ddec smpboot_thread_fn+460 c0000000001932c4 kthread+308 c00000000000dd58 start_kernel_thread+20 , cpuhp/2, 33]: 1 @[ 80000007642b9b6c 0x80000007642b9b6c c000000000206268 partition_sched_domains_locked+1304 c0000000002cbf08 rebuild_sched_domains_locked+216 c0000000002cfd5c cpuset_handle_hotplug+1148 c0000000001b3178 sched_cpu_activate+664 c000000000156fc0 cpuhp_invoke_callback+480 c000000000157974 cpuhp_thread_fun+244 c00000000019ddec smpboot_thread_fn+460 c0000000001932c4 kthread+308 c00000000000dd58 start_kernel_thread+20 , cpuhp/3, 38]: 1 + bpftrace -e 'kfunc:vmlinux:build_sched_domains {@[kstack(raw), comm, tid]=count();}' Attaching 1 probe... + chcpu -d 2-3 CPU 2 disabled CPU 3 disabled + kill 35243 @[ c00800000343346c , cpuhp/3, 38]: 1 @[ c00800000343346c , cpuhp/2, 33]: 1 + bpftrace -e 'kprobe:build_sched_domains {@[kstack(raw), comm, tid]=count();}' Attaching 1 probe... + chcpu -e 2-3 CPU 2 enabled CPU 3 enabled + kill 35249 @[ 80000007642befac c000000000206268 c0000000002cbf08 c0000000002cfd5c c0000000001b3178 c000000000156fc0 c000000000157974 c00000000019ddec c0000000001932c4 c00000000000dd58 , cpuhp/3, 38]: 1 @[ 80000007524b425c c000000000206268 c0000000002cbf08 c0000000002cfd5c c0000000001b3178 c000000000156fc0 c000000000157974 c00000000019ddec c0000000001932c4 c00000000000dd58 , cpuhp/2, 33]: 1 > > > Naveen N Rao (11): > powerpc/kprobes: Use ftrace to determine if a probe is at function > entry > powerpc/ftrace: Unify 32-bit and 64-bit ftrace entry code > powerpc/module_64: Convert #ifdef to IS_ENABLED() > powerpc/ftrace: Remove pointer to struct module from dyn_arch_ftrace > kbuild: Add generic hook for architectures to use before the final > vmlinux link > powerpc64/ftrace: Move ftrace sequence out of line > powerpc/ftrace: Add support for DYNAMIC_FTRACE_WITH_CALL_OPS > powerpc/ftrace: Add support for DYNAMIC_FTRACE_WITH_DIRECT_CALLS > samples/ftrace: Add support for ftrace direct samples on powerpc > powerpc64/bpf: Fold bpf_jit_emit_func_call_hlp() into > bpf_jit_emit_func_call_rel() > powerpc64/bpf: Add support for bpf trampolines > > arch/Kconfig | 3 + > arch/powerpc/Kconfig | 9 + > arch/powerpc/Makefile | 8 + > arch/powerpc/include/asm/ftrace.h | 29 +- > arch/powerpc/include/asm/module.h | 5 + > arch/powerpc/include/asm/ppc-opcode.h | 14 + > arch/powerpc/kernel/asm-offsets.c | 11 + > arch/powerpc/kernel/kprobes.c | 18 +- > arch/powerpc/kernel/module_64.c | 67 +- > arch/powerpc/kernel/trace/ftrace.c | 269 +++++++- > arch/powerpc/kernel/trace/ftrace_64_pg.c | 73 +- > arch/powerpc/kernel/trace/ftrace_entry.S | 210 ++++-- > arch/powerpc/kernel/vmlinux.lds.S | 3 +- > arch/powerpc/net/bpf_jit.h | 11 + > arch/powerpc/net/bpf_jit_comp.c | 702 +++++++++++++++++++- > arch/powerpc/net/bpf_jit_comp32.c | 7 +- > arch/powerpc/net/bpf_jit_comp64.c | 68 +- > arch/powerpc/tools/Makefile | 10 + > arch/powerpc/tools/gen-ftrace-pfe-stubs.sh | 49 ++ > samples/ftrace/ftrace-direct-modify.c | 85 ++- > samples/ftrace/ftrace-direct-multi-modify.c | 101 ++- > samples/ftrace/ftrace-direct-multi.c | 79 ++- > samples/ftrace/ftrace-direct-too.c | 83 ++- > samples/ftrace/ftrace-direct.c | 69 +- > scripts/Makefile.vmlinux | 8 + > scripts/link-vmlinux.sh | 11 +- > 26 files changed, 1813 insertions(+), 189 deletions(-) > create mode 100644 arch/powerpc/tools/Makefile > create mode 100755 arch/powerpc/tools/gen-ftrace-pfe-stubs.sh > > > base-commit: e2b06d707dd067509cdc9ceba783c06fa6a551c2 > prerequisite-patch-id: a1d50e589288239d5a8b1c1f354cd4737057c9d3 > prerequisite-patch-id: da4142d56880861bd0ad7ad7087c9e2670a2ee54 > prerequisite-patch-id: 609d292e054b2396b603890522a940fa0bdfb6d8 > prerequisite-patch-id: 6f7213fb77b1260defbf43be0e47bff9c80054cc > prerequisite-patch-id: ad3b71bf071ae4ba1bee5b087e61a2055772a74f > -- > 2.45.2 >
