diff options
| author | dillon <dillon@FreeBSD.org> | 2001-10-31 03:06:33 +0000 |
|---|---|---|
| committer | dillon <dillon@FreeBSD.org> | 2001-10-31 03:06:33 +0000 |
| commit | b11fa1d14dcd0c423c44976ff988b593de218a89 (patch) | |
| tree | a1f4c581b424a7ec9997c2852806b620613051fe /sys/amd64 | |
| parent | de8bc4ba10fb07aa68c4cd0d79b35529c6b1b958 (diff) | |
| download | FreeBSD-src-b11fa1d14dcd0c423c44976ff988b593de218a89.zip FreeBSD-src-b11fa1d14dcd0c423c44976ff988b593de218a89.tar.gz | |
Don't let pmap_object_init_pt() exhaust all available free pages
(allocating pv entries w/ zalloci) when called in a loop due to
an madvise(). It is possible to completely exhaust the free page list and
cause a system panic when an expected allocation fails.
Diffstat (limited to 'sys/amd64')
| -rw-r--r-- | sys/amd64/amd64/pmap.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index 5912074..edd0758 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -2546,7 +2546,7 @@ retry: psize = i386_btop(size); if ((object->type != OBJT_VNODE) || - (limit && (psize > MAX_INIT_PT) && + ((limit & MAP_PREFAULT_PARTIAL) && (psize > MAX_INIT_PT) && (object->resident_page_count > MAX_INIT_PT))) { return; } @@ -2577,6 +2577,14 @@ retry: if (tmpidx >= psize) { continue; } + /* + * don't allow an madvise to blow away our really + * free pages allocating pv entries. + */ + if ((limit & MAP_PREFAULT_MADVISE) && + cnt.v_free_count < cnt.v_free_reserved) { + break; + } if (((p->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) && (p->busy == 0) && (p->flags & (PG_BUSY | PG_FICTITIOUS)) == 0) { @@ -2595,6 +2603,14 @@ retry: * else lookup the pages one-by-one. */ for (tmpidx = 0; tmpidx < psize; tmpidx += 1) { + /* + * don't allow an madvise to blow away our really + * free pages allocating pv entries. + */ + if ((limit & MAP_PREFAULT_MADVISE) && + cnt.v_free_count < cnt.v_free_reserved) { + break; + } p = vm_page_lookup(object, tmpidx + pindex); if (p && ((p->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) && |
