Commit 0286b5ea authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Rusty Russell
Browse files

lib/bug: Use RCU list ops for module_bug_list

Actually since module_bug_list should be used in BUG context,
we may not need this. But for someone who want to use this
from normal context, this makes module_bug_list an RCU list.

Signed-off-by: default avatarMasami Hiramatsu <>
Signed-off-by: default avatarRusty Russell <>
parent 461e34ae
......@@ -1850,9 +1850,10 @@ static void free_module(struct module *mod)
/* Unlink carefully: kallsyms could be walking list. */
/* Wait for RCU synchronizing before releasing mod->list. */
/* Remove this module from bug list, this uses list_del_rcu */
/* Wait for RCU synchronizing before releasing mod->list and buglist. */
/* This may be NULL, but that's OK */
......@@ -64,16 +64,22 @@ static LIST_HEAD(module_bug_list);
static const struct bug_entry *module_find_bug(unsigned long bugaddr)
struct module *mod;
const struct bug_entry *bug = NULL;
list_for_each_entry(mod, &module_bug_list, bug_list) {
const struct bug_entry *bug = mod->bug_table;
list_for_each_entry_rcu(mod, &module_bug_list, bug_list) {
unsigned i;
bug = mod->bug_table;
for (i = 0; i < mod->num_bugs; ++i, ++bug)
if (bugaddr == bug_addr(bug))
return bug;
goto out;
return NULL;
bug = NULL;
return bug;
void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
......@@ -99,13 +105,15 @@ void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
* Strictly speaking this should have a spinlock to protect against
* traversals, but since we only traverse on BUG()s, a spinlock
* could potentially lead to deadlock and thus be counter-productive.
* Thus, this uses RCU to safely manipulate the bug list, since BUG
* must run in non-interruptive state.
list_add(&mod->bug_list, &module_bug_list);
list_add_rcu(&mod->bug_list, &module_bug_list);
void module_bug_cleanup(struct module *mod)
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