Unchanged and unpatchable function moves from .text to .text.unlikely about kpatch HOT 5 CLOSED

repro-1386.tar.gz

Note that cpumask_weight() moves from .text.cpumask_weight to .text.unlikely.cpumask_weight, but otherwise carries no object code differences:

$ diff -upr \
      <(objdump -Dr -j.text.cpumask_weight          proc.ORIG.o) \
      <(objdump -Dr -j.text.unlikely.cpumask_weight proc.PATCHED.o)
--- /dev/fd/63  2024-04-15 14:53:36.281721258 -0400
+++ /dev/fd/62  2024-04-15 14:53:36.282721251 -0400
@@ -1,8 +1,8 @@
 
-proc.ORIG.o:     file format elf64-x86-64
+proc.PATCHED.o:     file format elf64-x86-64
 
 
-Disassembly of section .text.cpumask_weight:
+Disassembly of section .text.unlikely.cpumask_weight:
 
 0000000000000000 <__pfx_cpumask_weight>:
    0:  90                      nop

cpumask_weight() is included because create-diff-object considers the section change as allowed and marks the symbol as CHANGED:

static void kpatch_compare_correlated_symbol(struct symbol *sym)
{

	[ ... snip ... ]

	/*
	 * If two symbols are correlated but their sections are not, then the
	 * symbol has changed sections.  This is only allowed if the symbol is
	 * moving out of an ignored section, or moving between normal/hot/unlikely
	 * subsections.
	 */
	if (sym1->sec && sym2->sec && sym1->sec->twin != sym2->sec) {
		if ((sym2->sec->twin && sym2->sec->twin->ignore) ||
		    kpatch_subsection_changed(sym1->sec, sym2->sec))
			sym->status = CHANGED;
		else
			DIFF_FATAL("symbol changed sections: %s", sym1->name);
	}

	[ ... snip ... ]

The CHANGED status means that we will be trying to kpatch the original function with the new one.

from kpatch.

This issue has been open for 30 days with no activity and no assignee. It will be closed in 7 days unless a comment is added.

from kpatch.

This issue was closed because it was inactive for 7 days after being marked stale.

from kpatch.

This issue has been open for 30 days with no activity and no assignee. It will be closed in 7 days unless a comment is added.

from kpatch.

This issue was closed because it was inactive for 7 days after being marked stale.

from kpatch.