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Code Issues Releases Activity

Properly lock the vm space when accessing the memory in a process. This

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fix could solve some "interesting" problems that could happen during
process rundown.
This commit is contained in:
John Dyson 1996-06-11 23:52:27 +00:00
parent 47dcd2e56c
commit dc48d43a6c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=16308
2 changed files with 28 additions and 4 deletions
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16
sys/fs/procfs/procfs_mem.c
View File

@ -37,7 +37,7 @@
*
* @(#)procfs_mem.c 8.4 (Berkeley) 1/21/94
*
* $Id: procfs_mem.c,v 1.16 1996/01/24 18:41:06 peter Exp $
* $Id: procfs_mem.c,v 1.17 1996/01/25 06:05:38 peter Exp $
*/
/*
@ -73,6 +73,17 @@ procfs_rwmem(p, uio)
{
int error;
int writing;
struct vmspace *vm;
/*
* if the vmspace is in the midst of being deallocated or the
* process is exiting, don't try to grab anything. The page table
* usage in that process can be messed up.
*/
vm = p->p_vmspace;
if ((p->p_flag & P_WEXIT) || (vm->vm_refcnt < 1))
return EFAULT;
++vm->vm_refcnt;
writing = uio->uio_rw == UIO_WRITE;
@ -144,7 +155,7 @@ procfs_rwmem(p, uio)
/*
* The map we want...
*/
map = &p->p_vmspace->vm_map;
map = &vm->vm_map;
/*
* Check the permissions for the area we're interested
@ -230,6 +241,7 @@ procfs_rwmem(p, uio)
VM_PROT_READ|VM_PROT_EXECUTE, 0);
} while (error == 0 && uio->uio_resid > 0);
vmspace_free(vm);
return (error);
}

16
sys/miscfs/procfs/procfs_mem.c
View File

@ -37,7 +37,7 @@
*
* @(#)procfs_mem.c 8.4 (Berkeley) 1/21/94
*
* $Id: procfs_mem.c,v 1.16 1996/01/24 18:41:06 peter Exp $
* $Id: procfs_mem.c,v 1.17 1996/01/25 06:05:38 peter Exp $
*/
/*
@ -73,6 +73,17 @@ procfs_rwmem(p, uio)
{
int error;
int writing;
struct vmspace *vm;
/*
* if the vmspace is in the midst of being deallocated or the
* process is exiting, don't try to grab anything. The page table
* usage in that process can be messed up.
*/
vm = p->p_vmspace;
if ((p->p_flag & P_WEXIT) || (vm->vm_refcnt < 1))
return EFAULT;
++vm->vm_refcnt;
writing = uio->uio_rw == UIO_WRITE;
@ -144,7 +155,7 @@ procfs_rwmem(p, uio)
/*
* The map we want...
*/
map = &p->p_vmspace->vm_map;
map = &vm->vm_map;
/*
* Check the permissions for the area we're interested
@ -230,6 +241,7 @@ procfs_rwmem(p, uio)
VM_PROT_READ|VM_PROT_EXECUTE, 0);
} while (error == 0 && uio->uio_resid > 0);
vmspace_free(vm);
return (error);
}