[src/trunk]: src/sys/kern db_show_callout(): struct callout_cpu and cpu_info ...

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

details:   https://anonhg.NetBSD.org/src/rev/03a55fbed190
branches:  trunk
changeset: 933900:03a55fbed190
user:      rin <rin%NetBSD.org@localhost>
date:      Sun May 31 08:33:47 2020 +0000

description:
db_show_callout(): struct callout_cpu and cpu_info are too much for stack.

XXX
DDB can be running in the interrupt context, e.g., when activated from
console. Therefore, use kmem_intr_alloc(9) instead of kmem_alloc(9).

Frame size, e.g. for m68k, becomes:
    9212 (oops!) --> 0

diffstat:

 sys/kern/kern_timeout.c |  42 +++++++++++++++++++++++++++++-------------
 1 files changed, 29 insertions(+), 13 deletions(-)

diffs (80 lines):

diff -r c1315236d82b -r 03a55fbed190 sys/kern/kern_timeout.c
--- a/sys/kern/kern_timeout.c   Sun May 31 08:05:30 2020 +0000
+++ b/sys/kern/kern_timeout.c   Sun May 31 08:33:47 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_timeout.c,v 1.61 2020/04/19 20:35:29 ad Exp $     */
+/*     $NetBSD: kern_timeout.c,v 1.62 2020/05/31 08:33:47 rin Exp $    */
 
 /*-
  * Copyright (c) 2003, 2006, 2007, 2008, 2009, 2019 The NetBSD Foundation, Inc.
@@ -59,7 +59,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_timeout.c,v 1.61 2020/04/19 20:35:29 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_timeout.c,v 1.62 2020/05/31 08:33:47 rin Exp $");
 
 /*
  * Timeouts are kept in a hierarchical timing wheel.  The c_time is the
@@ -834,8 +834,9 @@
 void
 db_show_callout(db_expr_t addr, bool haddr, db_expr_t count, const char *modif)
 {
-       struct callout_cpu *cc, ccb;
-       struct cpu_info *ci, cib;
+       struct callout_cpu *cc, *ccp;
+       struct cpu_info *ci, *cip;
+       const size_t ccs = sizeof(*cc), cis = sizeof(*ci);
        int b;
 
 #ifndef CRASH
@@ -843,25 +844,40 @@
 #endif
        db_printf("    ticks  wheel               arg  func\n");
 
+       ccp = kmem_intr_alloc(ccs, KM_NOSLEEP); /* XXX ddb */
+       if (ccp == NULL) {
+               db_printf("%s: cannot allocate callout_cpu\n", __func__);
+               return;
+       }
+       cip = kmem_intr_alloc(cis, KM_NOSLEEP); /* XXX ddb */
+       if (cip == NULL) {
+               kmem_intr_free(ccp, ccs);
+               db_printf("%s: cannot allocate cpu_info\n", __func__);
+               return;
+       }
+
        /*
         * Don't lock the callwheel; all the other CPUs are paused
         * anyhow, and we might be called in a circumstance where
         * some other CPU was paused while holding the lock.
         */
        for (ci = db_cpu_first(); ci != NULL; ci = db_cpu_next(ci)) {
-               db_read_bytes((db_addr_t)ci, sizeof(cib), (char *)&cib);
-               cc = cib.ci_data.cpu_callout;
-               db_read_bytes((db_addr_t)cc, sizeof(ccb), (char *)&ccb);
-               db_show_callout_bucket(&ccb, &cc->cc_todo, &ccb.cc_todo);
+               db_read_bytes((db_addr_t)ci, cis, (char *)cip);
+               cc = cip->ci_data.cpu_callout;
+               db_read_bytes((db_addr_t)cc, ccs, (char *)ccp);
+               db_show_callout_bucket(ccp, &cc->cc_todo, &ccp->cc_todo);
        }
        for (b = 0; b < BUCKETS; b++) {
                for (ci = db_cpu_first(); ci != NULL; ci = db_cpu_next(ci)) {
-                       db_read_bytes((db_addr_t)ci, sizeof(cib), (char *)&cib);
-                       cc = cib.ci_data.cpu_callout;
-                       db_read_bytes((db_addr_t)cc, sizeof(ccb), (char *)&ccb);
-                       db_show_callout_bucket(&ccb, &cc->cc_wheel[b],
-                           &ccb.cc_wheel[b]);
+                       db_read_bytes((db_addr_t)ci, cis, (char *)cip);
+                       cc = cip->ci_data.cpu_callout;
+                       db_read_bytes((db_addr_t)cc, ccs, (char *)ccp);
+                       db_show_callout_bucket(ccp, &cc->cc_wheel[b],
+                           &ccp->cc_wheel[b]);
                }
        }
+
+       kmem_intr_free(ccp, ccs);
+       kmem_intr_free(cip, cis);
 }
 #endif /* DDB */