d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Do not call vm_page_lookup() from the ddb routine, namely from "show

Browse Source 
vmopag" implementation. The vm_page_lookup() code modifies splay tree
of the object pages, and asserts that object lock is taken. First issue
could cause kernel data corruption, and second one instantly panics the
INVARIANTS-enabled kernel.

Take the advantage of the fact that object->memq is ordered by page index,
and iterate over memq to calculate the runs.

While there, make the code slightly more style-compliant by moving
variables declarations to the right place.

Discussed with:	jhb, alc
Reviewed by:	alc
MFC after:	2 weeks
This commit is contained in:
kib 2009-04-23 21:09:47 +00:00
parent 3ca2800ae4
commit 504b87e710
1 changed files with 13 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
sys/vm/vm_object.c
View File

@ -2196,16 +2196,13 @@ vm_object_print(
DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
{
vm_object_t object;
int nl = 0;
int c;
vm_pindex_t fidx;
vm_paddr_t pa;
vm_page_t m, prev_m;
int rcount, nl, c;
nl = 0;
TAILQ_FOREACH(object, &vm_object_list, object_list) {
vm_pindex_t idx, fidx;
vm_pindex_t osize;
vm_paddr_t pa = -1;
int rcount;
vm_page_t m;
db_printf("new object: %p\n", (void *)object);
if (nl > 18) {
c = cngetc();
@ -2216,12 +2213,12 @@ DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
nl++;
rcount = 0;
fidx = 0;
osize = object->size;
if (osize > 128)
osize = 128;
for (idx = 0; idx < osize; idx++) {
m = vm_page_lookup(object, idx);
if (m == NULL) {
pa = -1;
TAILQ_FOREACH(m, &object->memq, listq) {
if (m->pindex > 128)
break;
if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL &&
prev_m->pindex + 1 != m->pindex) {
if (rcount) {
db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
(long)fidx, rcount, (long)pa);
@ -2234,10 +2231,7 @@ DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
nl++;
rcount = 0;
}
continue;
}
}
if (rcount &&
(VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
++rcount;
@ -2254,7 +2248,7 @@ DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
}
nl++;
}
fidx = idx;
fidx = m->pindex;
pa = VM_PAGE_TO_PHYS(m);
rcount = 1;
}