On Fri 2021-03-26 15:30:21, Miroslav Benes wrote:
> Livepatch sends a fake signal to all remaining blocking tasks of a
> running transition after a set period of time. It uses TIF_SIGPENDING
> flag for the purpose. Commit 12db8b690010 ("entry: Add support for
> TIF_NOTIFY_SIGNAL") added a generic infrastructure to achieve the same.
> Replace our bespoke solution with the generic one.
>
> Signed-off-by: Miroslav Benes <mbenes@xxxxxxx>
> ---
> Tested on x86_64, s390x and ppc64le archs.
>
> kernel/livepatch/transition.c | 5 ++---
> kernel/signal.c | 3 +--
> 2 files changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
> index f6310f848f34..3a4beb9395c4 100644
> --- a/kernel/livepatch/transition.c
> +++ b/kernel/livepatch/transition.c
> @@ -9,6 +9,7 @@
>
> #include <linux/cpu.h>
> #include <linux/stacktrace.h>
> +#include <linux/tracehook.h>
> #include "core.h"
> #include "patch.h"
> #include "transition.h"
> @@ -369,9 +370,7 @@ static void klp_send_signals(void)
> * Send fake signal to all non-kthread tasks which are
> * still not migrated.
> */
> - spin_lock_irq(&task->sighand->siglock);
> - signal_wake_up(task, 0);
> - spin_unlock_irq(&task->sighand->siglock);
> + set_notify_signal(task);
> }
> }
> read_unlock(&tasklist_lock);
> diff --git a/kernel/signal.c b/kernel/signal.c
> index f2a1b898da29..e52cb82aaecd 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -181,8 +181,7 @@ void recalc_sigpending_and_wake(struct task_struct *t)
>
> void recalc_sigpending(void)
> {
> - if (!recalc_sigpending_tsk(current) && !freezing(current) &&
> - !klp_patch_pending(current))
> + if (!recalc_sigpending_tsk(current) && !freezing(current))
> clear_thread_flag(TIF_SIGPENDING);
>
> }
The original commit 43347d56c8d9dd732cee2 ("livepatch: send a fake
signal to all blocking tasks") did also:
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -40,6 +40,7 @@
#include <linux/cn_proc.h>
#include <linux/compiler.h>
#include <linux/posix-timers.h>
+#include <linux/livepatch.h>
#define CREATE_TRACE_POINTS
#include <trace/events/signal.h>
We could/should remove the include now.
Otherwise, it looks good to me. Well, I do not feel to be expert
in this are. Anyway, feel free to add:
Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
Best Regards,
Petr
