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authordyson <dyson@FreeBSD.org>1996-12-30 03:56:11 +0000
committerdyson <dyson@FreeBSD.org>1996-12-30 03:56:11 +0000
commitbc06bff4301fb86fcaae70db3ffb288fb4fa9624 (patch)
tree8d21599a817994d6ed249141f109d096e1cf2a30 /sys/vm
parent1d16d2e5a018aea3b92b0e8f18145691ed991d87 (diff)
downloadFreeBSD-src-bc06bff4301fb86fcaae70db3ffb288fb4fa9624.zip
FreeBSD-src-bc06bff4301fb86fcaae70db3ffb288fb4fa9624.tar.gz
EEEK!!! useracc and kernacc didn't lock their respective
maps. Additionally, eliminate the map->hint distortion associated with useracc. That may/may-not be the "right" thing to do -- but time will tell. Submitted by: Partially by Alan Cox <alc@cs.rice.edu>
Diffstat (limited to 'sys/vm')
-rw-r--r--sys/vm/vm_glue.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c
index 30cf0a9..c7567f8 100644
--- a/sys/vm/vm_glue.c
+++ b/sys/vm/vm_glue.c
@@ -59,7 +59,7 @@
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
- * $Id: vm_glue.c,v 1.55 1996/10/17 02:58:20 dyson Exp $
+ * $Id: vm_glue.c,v 1.56 1996/12/22 23:17:09 joerg Exp $
*/
#include "opt_rlimit.h"
@@ -126,7 +126,9 @@ kernacc(addr, len, rw)
saddr = trunc_page(addr);
eaddr = round_page(addr + len);
+ vm_map_lock_read(kernel_map);
rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
+ vm_map_unlock_read(kernel_map);
return (rv == TRUE);
}
@@ -137,6 +139,8 @@ useracc(addr, len, rw)
{
boolean_t rv;
vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
+ vm_map_t map;
+ vm_map_entry_t save_hint;
/*
* XXX - check separately to disallow access to user area and user
@@ -151,8 +155,18 @@ useracc(addr, len, rw)
|| (vm_offset_t) addr + len < (vm_offset_t) addr) {
return (FALSE);
}
- rv = vm_map_check_protection(&curproc->p_vmspace->vm_map,
+ map = &curproc->p_vmspace->vm_map;
+ vm_map_lock_read(map);
+ /*
+ * We save the map hint, and restore it. Useracc appears to distort
+ * the map hint unnecessarily.
+ */
+ save_hint = map->hint;
+ rv = vm_map_check_protection(map,
trunc_page(addr), round_page(addr + len), prot);
+ map->hint = save_hint;
+ vm_map_unlock_read(map);
+
return (rv == TRUE);
}
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