Merge tag 'modules-for-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux

65c61de9 · Linus Torvalds <[email protected]> · 2021-04-30 12:29:36 -07:00

Pull module updates from Jessica Yu:
 "Fix an age old bug involving jump_calls and static_labels when
  CONFIG_MODULE_UNLOAD=n.

  When CONFIG_MODULE_UNLOAD=n, it means you can't unload modules, so
  normally the __exit sections of a module are not loaded at all.
  However, dynamic code patching (jump_label, static_call, alternatives)
  can have sites in __exit sections even if __exit is never executed.

  Reported by Peter Zijlstra:
     'Alternatives, jump_labels and static_call all can have relocations
      into __exit code. Not loading it at all would be BAD.'

  Therefore, load the __exit sections even when CONFIG_MODULE_UNLOAD=n,
  and discard them after init"

* tag 'modules-for-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  module: treat exit sections the same as init sections when !CONFIG_MODULE_UNLOAD

Commit: 65c61de9d090edb8a3cfb3f45541e268eb2cdb13
Parents: c70a4be1 · 33121347

Merge commit. Changes below are compared with the first parent: c70a4be1.

Changes

1 files changed · +4 −5

File	Status	Add	Del	Content
kernel/module.c	modified	+4	−5	View file

kernel/module.c

View file

diff --git a/kernel/module.c b/kernel/module.c
index 20fb004..b5dd92e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2807,7 +2807,11 @@ void * __weak module_alloc(unsigned long size)
 
 bool __weak module_init_section(const char *name)
 {
+#ifndef CONFIG_MODULE_UNLOAD
+	return strstarts(name, ".init") || module_exit_section(name);
+#else
 	return strstarts(name, ".init");
+#endif
 }
 
 bool __weak module_exit_section(const char *name)
@@ -3121,11 +3125,6 @@ static int rewrite_section_headers(struct load_info *info, int flags)
 		 */
 		shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset;
 
-#ifndef CONFIG_MODULE_UNLOAD
-		/* Don't load .exit sections */
-		if (module_exit_section(info->secstrings+shdr->sh_name))
-			shdr->sh_flags &= ~(unsigned long)SHF_ALLOC;
-#endif
 	}
 
 	/* Track but don't keep modinfo and version sections. */