Re: [PATCH] panic: only warn about deprecated panic_print on write access

From: Feng Tang

Date: Wed Jan 07 2026 - 02:20:53 EST


On Wed, Jan 07, 2026 at 08:41:22AM +0200, Gal Pressman wrote:
> On 07/01/2026 5:00, Feng Tang wrote:
> >> @@ -1014,7 +1015,6 @@ static int panic_print_set(const char *val, const struct kernel_param *kp)
> >>
> >> static int panic_print_get(char *val, const struct kernel_param *kp)
> >> {
> >> - panic_print_deprecated();
> >
> > Actually this was intentional, in one of the patch version, this
> > panic_print_get() was not there but reusing the param_get_ulong().
> >
> > It was added later as sometimes developer do want to runtime check
> > the current 'panic_print' setting through /sys/module/kernel/parameters/
> > interface, and I thought it may be better to give the warning.
>
> I figured it would make sense to keep the behaviors consistent.

When people run 'sysctl -a', in 99.9% cases, the users don't care
'panic_print' or even don't know what 'panic_print' is, that's why
I think removing it makes sense.

But for a user running 'cat /sys/module/kernel/parameters/panic_rint',
giving a warning is meaningful.

If you insist so, the cleaner way would be

diff --git a/kernel/panic.c b/kernel/panic.c
index 0d52210a9e2b..86b927a695a0 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -1012,15 +1012,9 @@ static int panic_print_set(const char *val, const struct kernel_param *kp)
return param_set_ulong(val, kp);
}

-static int panic_print_get(char *val, const struct kernel_param *kp)
-{
- panic_print_deprecated();
- return param_get_ulong(val, kp);
-}
-
static const struct kernel_param_ops panic_print_ops = {
.set = panic_print_set,
- .get = panic_print_get,
+ .get = param_get_ulong,
};
__core_param_cb(panic_print, &panic_print_ops, &panic_print, 0644);