On Mon, Jun 28, 2021 at 11:22:20AM +0200, Peter Zijlstra wrote:
On Thu, Jun 24, 2021 at 06:32:25AM +0000, Liu, Yujie wrote:
> > > [ 222.094341] BUG: unable to handle page fault for address:
> > > ffffffff83ccffe0
> >
> > I *think* the below might help, can you try?
>
> Hi Peter Z,
>
> We try to apply the patch on commit e7bf1ba97afdd (jump_label, x86: Emit short JMP)
> A new BUG appeared before reaching the BUG reported in previous mail.
> Full dmesg in attachment.
> > @@ -555,6 +558,7 @@ static int __jump_label_mod_text_reserved(void *start, void
*end)
> > WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
> > if (!try_module_get(mod))
> > mod = NULL;
> > + init = mod->state == MODULE_STATE_COMING;
> > preempt_enable();
> >
> > if (!mod)
*groan*, I'm an idiot... There's an obvious NULL pointer deref right
there.
Let me try locally first before I send yet another dud.
OK, the below seems to work. Your report might've been easier to parse
if it had told me the failing test was:
tools/testing/selftests/ftrace/ftracetest
And that test would've been easier to use if it would just say wth was
missing from the .config :/
Let me go write up a proper patch and do the same for static_call.
---
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index ba39fbb1f8e7..af520ca26360 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -316,14 +316,16 @@ static int addr_conflict(struct jump_entry *entry, void *start, void
*end)
}
static int __jump_label_text_reserved(struct jump_entry *iter_start,
- struct jump_entry *iter_stop, void *start, void *end)
+ struct jump_entry *iter_stop, void *start, void *end, bool init)
{
struct jump_entry *iter;
iter = iter_start;
while (iter < iter_stop) {
- if (addr_conflict(iter, start, end))
- return 1;
+ if (init || !jump_entry_is_init(iter)) {
+ if (addr_conflict(iter, start, end))
+ return 1;
+ }
iter++;
}
@@ -561,7 +563,7 @@ static int __jump_label_mod_text_reserved(void *start, void *end)
ret = __jump_label_text_reserved(mod->jump_entries,
mod->jump_entries + mod->num_jump_entries,
- start, end);
+ start, end, mod->state == MODULE_STATE_COMING);
module_put(mod);
@@ -786,8 +788,9 @@ early_initcall(jump_label_init_module);
*/
int jump_label_text_reserved(void *start, void *end)
{
+ bool init = system_state < SYSTEM_RUNNING;
int ret = __jump_label_text_reserved(__start___jump_table,
- __stop___jump_table, start, end);
+ __stop___jump_table, start, end, init);
if (ret)
return ret;