Author: markj Date: Thu Jan 3 16:26:52 2019 New Revision: 342736 URL: https://svnweb.freebsd.org/changeset/base/342736
Log: Fix a use-after-free in the riscv pmap_release() implementation. Don't bother zeroing the top-level page before freeing it. Previously, the page was freed before being zeroed. Reviewed by: jhb, kib MFC after: 1 week Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D18720 Modified: head/sys/riscv/riscv/pmap.c Modified: head/sys/riscv/riscv/pmap.c ============================================================================== --- head/sys/riscv/riscv/pmap.c Thu Jan 3 16:24:03 2019 (r342735) +++ head/sys/riscv/riscv/pmap.c Thu Jan 3 16:26:52 2019 (r342736) @@ -1297,17 +1297,13 @@ pmap_release(pmap_t pmap) ("pmap_release: pmap resident count %ld != 0", pmap->pm_stats.resident_count)); - m = PHYS_TO_VM_PAGE(DMAP_TO_PHYS((vm_offset_t)pmap->pm_l1)); - vm_page_unwire_noq(m); - vm_page_free_zero(m); - - /* Remove pmap from the allpmaps list */ mtx_lock(&allpmaps_lock); LIST_REMOVE(pmap, pm_list); mtx_unlock(&allpmaps_lock); - /* Remove kernel pagetables */ - bzero(pmap->pm_l1, PAGE_SIZE); + m = PHYS_TO_VM_PAGE(DMAP_TO_PHYS((vm_offset_t)pmap->pm_l1)); + vm_page_unwire_noq(m); + vm_page_free(m); } #if 0 _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
