diff options
| author | Per Fogelstrom <pefo@cvs.openbsd.org> | 1998-08-30 13:42:15 +0000 |
|---|---|---|
| committer | Per Fogelstrom <pefo@cvs.openbsd.org> | 1998-08-30 13:42:15 +0000 |
| commit | a2c225fd21b562734f25815645ee93c9f2958aa6 (patch) | |
| tree | 867dd1f9c6669578e48ac448332749f560aeafc3 /sys | |
| parent | 5ef58ba424569c0766f9b4fba4308288f1449790 (diff) | |
OK, this is another fix for the infamous i386 "PTDI panic". This fix is the
same as is used in 'vslock()'. The situation when this occurs is when a
process tries to read or write to another process vm space and the _segment_
referenced have not yet been mapped. A certain way of crashing a system is
to debug a program larger than 4 Mb (yes, those critters exist!). Set a break
in an address above 4 Mb and pmap_enter panics because it can't fault in a
new ptd page since it is not the process itself that calls pmap_enter.
This is a fix, not a solution, but at least a user can't crash the kernel.
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/miscfs/procfs/procfs_mem.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/sys/miscfs/procfs/procfs_mem.c b/sys/miscfs/procfs/procfs_mem.c index 733c8e02753..8953fe1b665 100644 --- a/sys/miscfs/procfs/procfs_mem.c +++ b/sys/miscfs/procfs/procfs_mem.c @@ -1,4 +1,4 @@ -/* $OpenBSD: procfs_mem.c,v 1.7 1997/09/11 05:26:14 millert Exp $ */ +/* $OpenBSD: procfs_mem.c,v 1.8 1998/08/30 13:42:14 pefo Exp $ */ /* $NetBSD: procfs_mem.c,v 1.8 1996/02/09 22:40:50 christos Exp $ */ /* @@ -157,9 +157,13 @@ procfs_rwmem(p, uio) */ if (!error && writing && object->shadow) { m = vm_page_lookup(object, off); - if (m == 0 || (m->flags & PG_COPYONWRITE)) + if (m == 0 || (m->flags & PG_COPYONWRITE)) { +#ifdef __i386__ + pmap_prefault(map, uva, 4); +#endif error = vm_fault(map, pageno, VM_PROT_WRITE, FALSE); + } } /* Find space in kernel_map for the page we're interested in */ |