[src/trunk]: src/sys/uvm uvm(9): Sprinkle assertions into uvm_map_findspace.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/6ad4b3a29f3c
branches:  trunk
changeset: 366659:6ad4b3a29f3c
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Jun 05 13:45:28 2022 +0000

description:
uvm(9): Sprinkle assertions into uvm_map_findspace.

May help to diagnose PR kern/51254.

diffstat:

 sys/uvm/uvm_map.c |  94 ++++++++++++++++++++++++++++++++++++++----------------
 1 files changed, 65 insertions(+), 29 deletions(-)

diffs (202 lines):

diff -r 026ddf1aa854 -r 6ad4b3a29f3c sys/uvm/uvm_map.c
--- a/sys/uvm/uvm_map.c Sun Jun 05 13:35:52 2022 +0000
+++ b/sys/uvm/uvm_map.c Sun Jun 05 13:45:28 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_map.c,v 1.399 2022/06/05 01:45:45 riastradh Exp $  */
+/*     $NetBSD: uvm_map.c,v 1.400 2022/06/05 13:45:28 riastradh Exp $  */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.399 2022/06/05 01:45:45 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.400 2022/06/05 13:45:28 riastradh Exp $");
 
 #include "opt_ddb.h"
 #include "opt_pax.h"
@@ -1778,6 +1778,29 @@
        return (0);
 }
 
+static void
+uvm_findspace_invariants(struct vm_map *map, vaddr_t orig_hint, vaddr_t length,
+    struct uvm_object *uobj, voff_t uoffset, vsize_t align, int flags,
+    vaddr_t hint, int line)
+{
+       const int topdown = map->flags & VM_MAP_TOPDOWN;
+
+       KASSERTMSG( topdown || hint >= orig_hint,
+           "map=%p hint=%#"PRIxVADDR" orig_hint=%#"PRIxVADDR
+           " length=%#"PRIxVSIZE" uobj=%p uoffset=%#llx align=%"PRIxVSIZE
+           " flags=%#x (uvm_map_findspace line %d)",
+           map, hint, orig_hint,
+           length, uobj, (unsigned long long)uoffset, align,
+           flags, line);
+       KASSERTMSG(!topdown || hint <= orig_hint,
+           "map=%p hint=%#"PRIxVADDR" orig_hint=%#"PRIxVADDR
+           " length=%#"PRIxVSIZE" uobj=%p uoffset=%#llx align=%"PRIxVSIZE
+           " flags=%#x (uvm_map_findspace line %d)",
+           map, hint, orig_hint,
+           length, uobj, (unsigned long long)uoffset, align,
+           flags, line);
+}
+
 /*
  * uvm_map_findspace: find "length" sized space in "map".
  *
@@ -1796,10 +1819,14 @@
     vaddr_t *result /* OUT */, struct uvm_object *uobj, voff_t uoffset,
     vsize_t align, int flags)
 {
+#define        INVARIANTS()                                                          \
+       uvm_findspace_invariants(map, orig_hint, length, uobj, uoffset, align,\
+           flags, hint, __LINE__)
        struct vm_map_entry *entry;
        struct vm_map_entry *child, *prev, *tmp;
        vaddr_t orig_hint __diagused;
        const int topdown = map->flags & VM_MAP_TOPDOWN;
+       int avail;
        UVMHIST_FUNC(__func__);
        UVMHIST_CALLARGS(maphist, "(map=%#jx, hint=%#jx, len=%ju, flags=%#jx...",
            (uintptr_t)map, hint, length, flags);
@@ -1837,6 +1864,7 @@
                return (NULL);
        }
        orig_hint = hint;
+       INVARIANTS();
 
        UVMHIST_LOG(maphist,"<- VA %#jx vs range [%#jx->%#jx]",
            hint, vm_map_min(map), vm_map_max(map), 0);
@@ -1845,8 +1873,10 @@
         * hint may not be aligned properly; we need round up or down it
         * before proceeding further.
         */
-       if ((flags & UVM_FLAG_COLORMATCH) == 0)
+       if ((flags & UVM_FLAG_COLORMATCH) == 0) {
                uvm_map_align_va(&hint, align, topdown);
+               INVARIANTS();
+       }
 
        UVMHIST_LOG(maphist,"<- VA %#jx vs range [%#jx->%#jx]",
            hint, vm_map_min(map), vm_map_max(map), 0);
@@ -1931,8 +1961,10 @@
                        /*
                         * See if given hint fits in this gap.
                         */
-                       switch (uvm_map_space_avail(&hint, length,
-                           uoffset, align, flags, topdown, entry)) {
+                       avail = uvm_map_space_avail(&hint, length,
+                           uoffset, align, flags, topdown, entry);
+                       INVARIANTS();
+                       switch (avail) {
                        case 1:
                                goto found;
                        case -1:
@@ -1963,8 +1995,11 @@
 
        /* Check slot before any entry */
        hint = topdown ? entry->next->start - length : entry->end;
-       switch (uvm_map_space_avail(&hint, length, uoffset, align, flags,
-           topdown, entry)) {
+       INVARIANTS();
+       avail = uvm_map_space_avail(&hint, length, uoffset, align, flags,
+           topdown, entry);
+       INVARIANTS();
+       switch (avail) {
        case 1:
                goto found;
        case -1:
@@ -2031,8 +2066,11 @@
                        if (hint < tmp->end)
                                hint = tmp->end;
                }
-               switch (uvm_map_space_avail(&hint, length, uoffset, align,
-                   flags, topdown, tmp)) {
+               INVARIANTS();
+               avail = uvm_map_space_avail(&hint, length, uoffset, align,
+                   flags, topdown, tmp);
+               INVARIANTS();
+               switch (avail) {
                case 1:
                        entry = tmp;
                        goto found;
@@ -2053,8 +2091,11 @@
                KASSERT(orig_hint <= prev->end);
                hint = prev->end;
        }
-       switch (uvm_map_space_avail(&hint, length, uoffset, align,
-           flags, topdown, prev)) {
+       INVARIANTS();
+       avail = uvm_map_space_avail(&hint, length, uoffset, align,
+           flags, topdown, prev);
+       INVARIANTS();
+       switch (avail) {
        case 1:
                entry = prev;
                goto found;
@@ -2094,8 +2135,11 @@
                KASSERT(orig_hint <= tmp->end);
                hint = tmp->end;
        }
-       switch (uvm_map_space_avail(&hint, length, uoffset, align,
-           flags, topdown, tmp)) {
+       INVARIANTS();
+       avail = uvm_map_space_avail(&hint, length, uoffset, align,
+           flags, topdown, tmp);
+       INVARIANTS();
+       switch (avail) {
        case 1:
                entry = tmp;
                goto found;
@@ -2115,13 +2159,17 @@
         *       entry->next->start = VA of end of current gap
         */
 
+       INVARIANTS();
        for (;;) {
                /* Update hint for current gap. */
                hint = topdown ? entry->next->start - length : entry->end;
+               INVARIANTS();
 
                /* See if it fits. */
-               switch (uvm_map_space_avail(&hint, length, uoffset, align,
-                   flags, topdown, entry)) {
+               avail = uvm_map_space_avail(&hint, length, uoffset, align,
+                   flags, topdown, entry);
+               INVARIANTS();
+               switch (avail) {
                case 1:
                        goto found;
                case -1:
@@ -2150,20 +2198,7 @@
        SAVE_HINT(map, map->hint, entry);
        *result = hint;
        UVMHIST_LOG(maphist,"<- got it!  (result=%#jx)", hint, 0,0,0);
-       KASSERTMSG( topdown || hint >= orig_hint,
-           "map=%p hint=%#"PRIxVADDR" orig_hint=%#"PRIxVADDR
-           " length=%#"PRIxVSIZE" uobj=%p uoffset=%#llx align=%"PRIxVSIZE
-           " flags=%#x",
-           map, hint, orig_hint,
-           length, uobj, (unsigned long long)uoffset, align,
-           flags);
-       KASSERTMSG(!topdown || hint <= orig_hint,
-           "map=%p hint=%#"PRIxVADDR" orig_hint=%#"PRIxVADDR
-           " length=%#"PRIxVSIZE" uobj=%p uoffset=%#llx align=%"PRIxVSIZE
-           " flags=%#x",
-           map, hint, orig_hint,
-           length, uobj, (unsigned long long)uoffset, align,
-           flags);
+       INVARIANTS();
        KASSERT(entry->end <= hint);
        KASSERT(hint + length <= entry->next->start);
        return (entry);
@@ -2177,6 +2212,7 @@
        UVMHIST_LOG(maphist, "<- failed (notfound)", 0,0,0,0);
 
        return (NULL);
+#undef INVARIANTS
 }
 
 /*