Author: markj
Date: Thu Jul 14 18:49:05 2016
New Revision: 302854
URL: https://svnweb.freebsd.org/changeset/base/302854
Log:
Let DDB's buf printer handle NULL pointers in the buf page array.
A buf's b_pages and b_npages fields may be inconsistent after a panic.
For instance, vfs_vmio_invalidate() sets b_npages to zero only after all
pages are unwired and their page array entries are cleared.
MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division
Modified:
head/sys/kern/vfs_bio.c
Modified: head/sys/kern/vfs_bio.c
==============================================================================
--- head/sys/kern/vfs_bio.c Thu Jul 14 17:31:29 2016 (r302853)
+++ head/sys/kern/vfs_bio.c Thu Jul 14 18:49:05 2016 (r302854)
@@ -4725,8 +4725,12 @@ DB_SHOW_COMMAND(buffer, db_show_buffer)
for (i = 0; i < bp->b_npages; i++) {
vm_page_t m;
m = bp->b_pages[i];
- db_printf("(%p, 0x%lx, 0x%lx)", (void *)m->object,
- (u_long)m->pindex, (u_long)VM_PAGE_TO_PHYS(m));
+ if (m != NULL)
+ db_printf("(%p, 0x%lx, 0x%lx)", m->object,
+ (u_long)m->pindex,
+ (u_long)VM_PAGE_TO_PHYS(m));
+ else
+ db_printf("( ??? )");
if ((i + 1) < bp->b_npages)
db_printf(",");
}
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