[RFC PATCH 13/24] fork: let new tasks start with task work
From: Li Chen <hidden>
Date: 2026-07-16 14:40:06
Also in:
linux-arch, linux-doc, linux-fsdevel, linux-kselftest, linux-mm, linux-security-module, lkml
Subsystem:
exec & binfmt api, elf, memory management - core, scheduler, the rest · Maintainers:
Kees Cook, Andrew Morton, David Hildenbrand, Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
Process builders need to run setup in the child before its first return to userspace without storing a kernel callback in architecture-specific saved registers. Allow an internal clone caller to supply task work. Queue it after the last ordinary fork failure check, while the child is still TASK_NEW. A NULL work pointer leaves existing clone callers unchanged. Assisted-by: Codex:gpt-5.6-sol Signed-off-by: Li Chen <redacted> --- include/linux/sched/task.h | 2 ++ kernel/fork.c | 6 ++++++ 2 files changed, 8 insertions(+)
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index 5b7facf12b33b..830de99aabaed 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h@@ -43,6 +43,8 @@ struct kernel_clone_args { int idle; int (*fn)(void *); void *fn_arg; + /* Run before the new task first returns to userspace. */ + struct callback_head *task_work; struct cgroup *cgrp; struct css_set *cset; bool embryonic_exec;
diff --git a/kernel/fork.c b/kernel/fork.c
index e3ade83b2d4e2..c0584eaa74711 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c@@ -109,6 +109,7 @@ #include <uapi/linux/pidfd.h> #include <linux/pidfs.h> #include <linux/tick.h> +#include <linux/task_work.h> #include <linux/unwind_deferred.h> #include <linux/pgalloc.h> #include <linux/uaccess.h>
@@ -2504,6 +2505,11 @@ __latent_entropy struct task_struct *copy_process( retval = -EINTR; goto bad_fork_core_free; } + if (args->task_work) { + retval = task_work_add(p, args->task_work, TWA_RESUME); + if (WARN_ON_ONCE(retval)) + goto bad_fork_core_free; + } /* No more failure paths after this point. */
--
2.52.0