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Commit c660e306 authored by qctecmdr Service's avatar qctecmdr Service Committed by Gerrit - the friendly Code Review server
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Merge "mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct"

parents 1f116377 1022f84e

fs/proc/base.c

+4 −4
Original line number Diff line number Diff line
@@ -219,12 +219,12 @@ static ssize_t get_mm_cmdline(struct mm_struct *mm, char __user *buf, 
	if (!mm->env_end)

		return 0;



	down_read(&mm->mmap_sem);

	spin_lock(&mm->arg_lock);

	arg_start = mm->arg_start;

	arg_end = mm->arg_end;

	env_start = mm->env_start;

	env_end = mm->env_end;

	up_read(&mm->mmap_sem);

	spin_unlock(&mm->arg_lock);



	if (arg_start >= arg_end)

		return 0;
@@ -902,10 +902,10 @@ static ssize_t environ_read(struct file *file, char __user *buf, 
	if (!mmget_not_zero(mm))

		goto free;



	down_read(&mm->mmap_sem);

	spin_lock(&mm->arg_lock);

	env_start = mm->env_start;

	env_end = mm->env_end;

	up_read(&mm->mmap_sem);

	spin_unlock(&mm->arg_lock);



	while (count > 0) {

		size_t this_len, max_len;

include/linux/mm_types.h

+2 −0
Original line number Diff line number Diff line
@@ -430,6 +430,8 @@ struct mm_struct { 
	unsigned long exec_vm;		/* VM_EXEC & ~VM_WRITE & ~VM_STACK */

	unsigned long stack_vm;		/* VM_STACK */

	unsigned long def_flags;



	spinlock_t arg_lock; /* protect the below fields */

	unsigned long start_code, end_code, start_data, end_data;

	unsigned long start_brk, brk, start_stack;

	unsigned long arg_start, arg_end, env_start, env_end;

kernel/fork.c

+1 −0
Original line number Diff line number Diff line
@@ -828,6 +828,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, 
	mm->pinned_vm = 0;

	memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));

	spin_lock_init(&mm->page_table_lock);

	spin_lock_init(&mm->arg_lock);

	mm_init_cpumask(mm);

	mm_init_aio(mm);

	mm_init_owner(mm, p);

kernel/sys.c

+8 −2
Original line number Diff line number Diff line
@@ -1954,7 +1954,11 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data 
			return error;

	}



	down_write(&mm->mmap_sem);

	/*

	 * arg_lock protects concurent updates but we still need mmap_sem for

	 * read to exclude races with sys_brk.

	 */

	down_read(&mm->mmap_sem);



	/*

	 * We don't validate if these members are pointing to
@@ -1968,6 +1972,7 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data 
	 *    to any problem in kernel itself

	 */



	spin_lock(&mm->arg_lock);

	mm->start_code	= prctl_map.start_code;

	mm->end_code	= prctl_map.end_code;

	mm->start_data	= prctl_map.start_data;
@@ -1979,6 +1984,7 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data 
	mm->arg_end	= prctl_map.arg_end;

	mm->env_start	= prctl_map.env_start;

	mm->env_end	= prctl_map.env_end;

	spin_unlock(&mm->arg_lock);



	/*

	 * Note this update of @saved_auxv is lockless thus
@@ -1991,7 +1997,7 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data 
	if (prctl_map.auxv_size)

		memcpy(mm->saved_auxv, user_auxv, sizeof(user_auxv));



	up_write(&mm->mmap_sem);

	up_read(&mm->mmap_sem);

	return 0;

}

#endif /* CONFIG_CHECKPOINT_RESTORE */

mm/init-mm.c

+1 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ struct mm_struct init_mm = { 
	.mm_count	= ATOMIC_INIT(1),

	.mmap_sem	= __RWSEM_INITIALIZER(init_mm.mmap_sem),

	.page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),

	.arg_lock	=  __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),

	.mmlist		= LIST_HEAD_INIT(init_mm.mmlist),

	.user_ns	= &init_user_ns,

	INIT_MM_CONTEXT(init_mm)