On Wed, 27 May 2026 20:35:23 +0800, wanghan@linux.alibaba.com wrote:

On an affected RISC-V QEMU boot with both CONFIG_FTRACE_SORT_STARTUP_TEST
and CONFIG_FTRACE_STARTUP_TEST enabled, the sort check still passes
while ftrace reports zero usable entries and the early selftests fail:

  [    0.000000] ftrace section at ffffffff8101da98 sorted properly
  [    0.000000] ftrace: allocating 0 entries in 128 pages
  [    0.054999] Testing tracer function: .. no entries found ..FAILED!
  [    0.172407] tracer: function failed selftest, disabling
  [    0.178186] Failed to init function_graph tracer, init returned -19

Handle RISC-V like arm64 for the function-range check and allow
patchable entries up to 8 bytes before the function address.

With this fix, a RISC-V QEMU smoke boot with ftrace startup tests shows
the vmlinux ftrace table is populated and dynamic ftrace still works:

  [    0.000000] ftrace: allocating 46749 entries in 184 pages
  [    0.051115] Testing tracer function: PASSED
  [    1.283782] Testing dynamic ftrace: PASSED
  [    6.275456] Testing tracer function_graph: PASSED

Fixes: 0ca1724b56af ("riscv: ftrace: select HAVE_BUILDTIME_MCOUNT_SORT")

Oops, sorry for missing that. Thanks for the quick fix!

Reviewed-by: Chen Pei <redacted>