hi,
Martynas reported bpf_get_func_ip returning +4 address when
CONFIG_X86_KERNEL_IBT option is enabled and I found there are
some failing bpf tests when this option is enabled.
The CONFIG_X86_KERNEL_IBT option adds endbr instruction at the
function entry, so the idea is to 'fix' entry ip for kprobe_multi
and trampoline probes, because they are placed on the function
entry.
For kprobes I only fixed the bpf test program to adjust ip based
on CONFIG_X86_KERNEL_IBT option. I'm not sure what the right fix
should be in here, because I think user should be aware where the
kprobe is placed, on the other hand we move the kprobe address if
its placed on top of endbr instruction.
v1 changes:
- read previous instruction in kprobe_multi link handler
and adjust entry_ip for CONFIG_X86_KERNEL_IBT option
- split first patch into 2 separate changes
- update changelogs
thanks,
jirka
---
Jiri Olsa (5):
ftrace: Keep the resolved addr in kallsyms_callback
bpf: Adjust kprobe_multi entry_ip for CONFIG_X86_KERNEL_IBT
bpf: Use given function address for trampoline ip arg
selftests/bpf: Disable kprobe attach test with offset for CONFIG_X86_KERNEL_IBT
selftests/bpf: Fix kprobe get_func_ip tests for CONFIG_X86_KERNEL_IBT
arch/x86/net/bpf_jit_comp.c | 9 ++++-----
kernel/trace/bpf_trace.c | 4 ++++
kernel/trace/ftrace.c | 3 +--
tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c | 25 ++++++++++++++++++++-----
tools/testing/selftests/bpf/progs/get_func_ip_test.c | 7 +++++--
tools/testing/selftests/bpf/progs/kprobe_multi.c | 2 +-
6 files changed, 35 insertions(+), 15 deletions(-)
