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kernel: Allow a kernel thread's name to be set in copy_process

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This patch allows kernel users to pass in the thread name so it can be
set during creation instead of having to use set_task_comm after the
thread is created.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
This commit is contained in:
Mike Christie 2023-03-10 16:03:23 -06:00 committed by Christian Brauner (Microsoft)
parent e0a98139c1
commit cf587db2ee
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GPG Key ID: 91C61BC06578DCA2
4 changed files with 12 additions and 4 deletions
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4
include/linux/sched/task.h
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@ -23,6 +23,7 @@ struct kernel_clone_args {
int __user *pidfd;
int __user *child_tid;
int __user *parent_tid;
const char *name;
int exit_signal;
unsigned long stack;
unsigned long stack_size;
@ -91,7 +92,8 @@ extern void exit_itimers(struct task_struct *);
extern pid_t kernel_clone(struct kernel_clone_args *kargs);
struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node);
struct task_struct *fork_idle(int);
extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
extern pid_t kernel_thread(int (*fn)(void *), void *arg, const char *name,
unsigned long flags);
extern pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags);
extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
int kernel_wait(pid_t pid, int *stat);

2
init/main.c
View File

@ -707,7 +707,7 @@ noinline void __ref rest_init(void)
rcu_read_unlock();
numa_default_policy();
pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
pid = kernel_thread(kthreadd, NULL, NULL, CLONE_FS | CLONE_FILES);
rcu_read_lock();
kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
rcu_read_unlock();

7
kernel/fork.c
View File

@ -2112,6 +2112,9 @@ static __latent_entropy struct task_struct *copy_process(
siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP));
}
if (args->name)
strscpy_pad(p->comm, args->name, sizeof(p->comm));
p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? args->child_tid : NULL;
/*
* Clear TID on mm_release()?
@ -2730,7 +2733,8 @@ pid_t kernel_clone(struct kernel_clone_args *args)
/*
* Create a kernel thread.
*/
pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
pid_t kernel_thread(int (*fn)(void *), void *arg, const char *name,
unsigned long flags)
{
struct kernel_clone_args args = {
.flags = ((lower_32_bits(flags) | CLONE_VM |
@ -2738,6 +2742,7 @@ pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
.exit_signal = (lower_32_bits(flags) & CSIGNAL),
.fn = fn,
.fn_arg = arg,
.name = name,
.kthread = 1,
};

3
kernel/kthread.c
View File

@ -396,7 +396,8 @@ static void create_kthread(struct kthread_create_info *create)
current->pref_node_fork = create->node;
#endif
/* We want our own signal handler (we take no signals by default). */
pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD);
pid = kernel_thread(kthread, create, NULL,
CLONE_FS | CLONE_FILES | SIGCHLD);
if (pid < 0) {
/* Release the structure when caller killed by a fatal signal. */
struct completion *done = xchg(&create->done, NULL);