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Commit 3d1b8cfd authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Greg Kroah-Hartman
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x86/mm: Use mm_alloc() in poking_init() 



commit 3f4c8211d982099be693be9aa7d6fc4607dff290 upstream.

Instead of duplicating init_mm, allocate a fresh mm. The advantage is
that mm_alloc() has much simpler dependencies. Additionally it makes
more conceptual sense, init_mm has no (and must not have) user state
to duplicate.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221025201057.816175235@infradead.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ddcf05fe

arch/x86/mm/init.c

+2 −1
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/swapops.h>

#include <linux/kmemleak.h>

#include <linux/sched/task.h>

#include <linux/sched/mm.h>



#include <asm/set_memory.h>

#include <asm/cpu_device_id.h>
@@ -736,7 +737,7 @@ void __init poking_init(void) 
	spinlock_t *ptl;

	pte_t *ptep;



	poking_mm = copy_init_mm();

	poking_mm = mm_alloc();

	BUG_ON(!poking_mm);



	/* Xen PV guests need the PGD to be pinned. */

include/linux/sched/task.h

+0 −1
Original line number Diff line number Diff line
@@ -93,7 +93,6 @@ extern long _do_fork(struct kernel_clone_args *kargs); 
extern bool legacy_clone_args_valid(const struct kernel_clone_args *kargs);

extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);

struct task_struct *fork_idle(int);

struct mm_struct *copy_init_mm(void);

extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);

extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);

kernel/fork.c

+0 −5
Original line number Diff line number Diff line
@@ -2335,11 +2335,6 @@ struct task_struct *fork_idle(int cpu) 
	return task;

}



struct mm_struct *copy_init_mm(void)

{

	return dup_mm(NULL, &init_mm);

}



/*

 *  Ok, this is the main fork-routine.

 *