diff options
| author | Feng Yang <yangfeng@kylinos.cn> | 2025-09-25 10:08:22 +0800 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2025-09-25 13:59:26 +0100 |
| commit | fd2f74f8f3d3c1a524637caf5bead9757fae4332 (patch) | |
| tree | e9a9186d44493ca48ef4bddb50c3f98bf1798706 | |
| parent | 195a1b7d8388c0ec2969a39324feb8bebf9bb907 (diff) | |
tracing: Fix the bug where bpf_get_stackid returns -EFAULT on the ARM64
When using bpf_program__attach_kprobe_multi_opts on ARM64 to hook a BPF program
that contains the bpf_get_stackid function, the BPF program fails
to obtain the stack trace and returns -EFAULT.
This is because ftrace_partial_regs omits the configuration of the pstate register,
leaving pstate at the default value of 0. When get_perf_callchain executes,
it uses user_mode(regs) to determine whether it is in kernel mode.
This leads to a misjudgment that the code is in user mode,
so perf_callchain_kernel is not executed and the function returns directly.
As a result, trace->nr becomes 0, and finally -EFAULT is returned.
Therefore, the assignment of the pstate register is added here.
Fixes: b9b55c8912ce ("tracing: Add ftrace_partial_regs() for converting ftrace_regs to pt_regs")
Closes: https://lore.kernel.org/bpf/20250919071902.554223-1-yangfeng59949@163.com/
Signed-off-by: Feng Yang <yangfeng@kylinos.cn>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | arch/arm64/include/asm/ftrace.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index bfe3ce9df197..ba7cf7fec5e9 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -153,6 +153,7 @@ ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs) regs->pc = afregs->pc; regs->regs[29] = afregs->fp; regs->regs[30] = afregs->lr; + regs->pstate = PSR_MODE_EL1h; return regs; } |