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| author |   Eric W. Biederman <ebiederm@xmission.com> | 2022-04-11 16:17:28 -0500 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2022-05-07 09:01:59 -0500 |
| commit | 36cb0e1cda645ee645b85a6ce652cb46a16e14e5 (patch) | |
| tree | f4c38b8a981df1a2f7fd4681c6cc4f6859893f0f | |
| parent | fork: Pass struct kernel_clone_args into copy_thread (diff) | |
| download | linux-dev-36cb0e1cda645ee645b85a6ce652cb46a16e14e5.tar.xz linux-dev-36cb0e1cda645ee645b85a6ce652cb46a16e14e5.zip | |
fork: Explicity test for idle tasks in copy_thread
The architectures ia64 and parisc have special handling for the idle
thread in copy_process. Add a flag named idle to kernel_clone_args
and use it to explicity test if an idle process is being created.
Fullfill the expectations of the rest of the copy_thread
implemetations and pass a function pointer in .stack from fork_idle().
This makes what is happening in copy_thread better defined, and is
useful to make idle threads less special.
Link: https://lkml.kernel.org/r/20220506141512.516114-3-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to '')
| -rw-r--r-- | arch/ia64/kernel/process.c | 2 | ||||
| -rw-r--r-- | arch/parisc/kernel/process.c | 2 | ||||
| -rw-r--r-- | include/linux/sched/task.h | 1 | ||||
| -rw-r--r-- | kernel/fork.c | 9 |
4 files changed, 12 insertions, 2 deletions
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c index 10d41ded05a5..8f010ae818bc 100644 --- a/arch/ia64/kernel/process.c +++ b/arch/ia64/kernel/process.c @@ -342,7 +342,7 @@ copy_thread(struct task_struct *p, const struct kernel_clone_args *args) ia64_drop_fpu(p); /* don't pick up stale state from a CPU's fph */ if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) { - if (unlikely(!user_stack_base)) { + if (unlikely(args->idle)) { /* fork_idle() called us */ return 0; } diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c index 129c17de45ba..30a5874ca845 100644 --- a/arch/parisc/kernel/process.c +++ b/arch/parisc/kernel/process.c @@ -224,7 +224,7 @@ copy_thread(struct task_struct *p, const struct kernel_clone_args *args) if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) { /* kernel thread */ memset(cregs, 0, sizeof(struct pt_regs)); - if (!usp) /* idle thread */ + if (args->idle) /* idle thread */ return 0; /* Must exit via ret_from_kernel_thread in order * to call schedule_tail() diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h index fcdcba231aac..3d6b99ce5408 100644 --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -33,6 +33,7 @@ struct kernel_clone_args { int cgroup; int io_thread; int kthread; + int idle; struct cgroup *cgrp; struct css_set *cset; }; diff --git a/kernel/fork.c b/kernel/fork.c index d39a248a8d8d..93d77ee921ff 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2544,12 +2544,21 @@ static inline void init_idle_pids(struct task_struct *idle) } } +static int idle_dummy(void *dummy) +{ + /* This function is never called */ + return 0; +} + struct task_struct * __init fork_idle(int cpu) { struct task_struct *task; struct kernel_clone_args args = { .flags = CLONE_VM, + .stack = (unsigned long)&idle_dummy, + .stack_size = (unsigned long)NULL, .kthread = 1, + .idle = 1, }; task = copy_process(&init_struct_pid, 0, cpu_to_node(cpu), &args); |