[PATCH V6 04/10] fork: Add USER_WORKER flag to ignore signals

Mike Christie
2021-11-29T19:49:42Z

From: Christian Brauner <christian.brauner@ubuntu.com>

Since this is mirroring kthread's sig ignore api introduced in

commit 10ab825bdef8 ("change kernel threads to ignore signals instead of
blocking them")

this patch adds an option flag, USER_WORKER_SIG_IGN, handled in
copy_process() after copy_sighand() and copy_signals() to ease the
transition from kthreads to this new api.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
include/linux/sched/task.h | 1 +
kernel/fork.c | 3 +++
2 files changed, 4 insertions(+)

diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index e094502b2eea..f8a658700075 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -21,6 +21,7 @@ struct css_set;
#define USER_WORKER BIT(0)
#define USER_WORKER_IO BIT(1)
#define USER_WORKER_NO_FILES BIT(2)
+#define USER_WORKER_SIG_IGN BIT(3)

struct kernel_clone_args {
u64 flags;
diff --git a/kernel/fork.c b/kernel/fork.c
index a47bec00f37c..c9152596a285 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2211,6 +2211,9 @@ static __latent_entropy struct task_struct *copy_process(
if (retval)
goto bad_fork_cleanup_io;

+ if (args->worker_flags & USER_WORKER_SIG_IGN)
+ ignore_signals(p);
+
stackleak_task_init(p);

if (pid != &init_struct_pid) {
--
2.25.1