[src/trunk]: src/sys/kern coredump_note_elf{32,64}(): avoid allcating registe...

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

details:   https://anonhg.NetBSD.org/src/rev/d71aba657467
branches:  trunk
changeset: 1010607:d71aba657467
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sat May 30 16:12:56 2020 +0000

description:
coredump_note_elf{32,64}(): avoid allcating register state buffers on
the stack; they could be large.

diffstat:

 sys/kern/core_elf32.c |  51 +++++++++++++++++++++++++++++++--------------------
 1 files changed, 31 insertions(+), 20 deletions(-)

diffs (95 lines):

diff -r cf5225f70d94 -r d71aba657467 sys/kern/core_elf32.c
--- a/sys/kern/core_elf32.c     Sat May 30 16:03:58 2020 +0000
+++ b/sys/kern/core_elf32.c     Sat May 30 16:12:56 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: core_elf32.c,v 1.63 2020/05/23 23:42:43 ad Exp $       */
+/*     $NetBSD: core_elf32.c,v 1.64 2020/05/30 16:12:56 thorpej Exp $  */
 
 /*
  * Copyright (c) 2001 Wasabi Systems, Inc.
@@ -40,7 +40,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(1, "$NetBSD: core_elf32.c,v 1.63 2020/05/23 23:42:43 ad Exp $");
+__KERNEL_RCSID(1, "$NetBSD: core_elf32.c,v 1.64 2020/05/30 16:12:56 thorpej Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_compat_netbsd32.h"
@@ -478,47 +478,58 @@
        return error;
 }
 
-static int
-ELFNAMEEND(coredump_note)(struct lwp *l, struct note_state *ns)
-{
-       int error;
+struct elf_coredump_note_data {
        char name[64];
        elf_lwpstatus els;
        elf_reg intreg;
 #ifdef PT_GETFPREGS
        elf_fpreg freg;
+#endif
+};
+
+static int
+ELFNAMEEND(coredump_note)(struct lwp *l, struct note_state *ns)
+{
+       struct elf_coredump_note_data *d;
+#ifdef PT_GETFPREGS
        size_t freglen;
 #endif
+       int error;
 
-       snprintf(name, sizeof(name), "%s@%d",
+       d = kmem_alloc(sizeof(*d), KM_SLEEP);
+
+       snprintf(d->name, sizeof(d->name), "%s@%d",
            ELF_NOTE_NETBSD_CORE_NAME, l->l_lid);
 
-       elf_read_lwpstatus(l, &els);
+       elf_read_lwpstatus(l, &d->els);
 
-       ELFNAMEEND(coredump_savenote)(ns, PT_LWPSTATUS, name, &els,
-           sizeof(els));
+       ELFNAMEEND(coredump_savenote)(ns, PT_LWPSTATUS, d->name, &d->els,
+           sizeof(d->els));
 
-       error = elf_process_read_regs(l, &intreg);
+       error = elf_process_read_regs(l, &d->intreg);
        if (error)
-               return (error);
+               goto out;
 
-       ELFNAMEEND(coredump_savenote)(ns, PT_GETREGS, name, &intreg,
-           sizeof(intreg));
+       ELFNAMEEND(coredump_savenote)(ns, PT_GETREGS, d->name, &d->intreg,
+           sizeof(d->intreg));
 
 #ifdef PT_GETFPREGS
-       freglen = sizeof(freg);
-       error = elf_process_read_fpregs(l, &freg, &freglen);
+       freglen = sizeof(d->freg);
+       error = elf_process_read_fpregs(l, &d->freg, &freglen);
        if (error)
-               return (error);
+               goto out;
 
-       ELFNAMEEND(coredump_savenote)(ns, PT_GETFPREGS, name, &freg, freglen);
+       ELFNAMEEND(coredump_savenote)(ns, PT_GETFPREGS, d->name, &d->freg,
+           freglen);
 #endif
 
 #ifdef COREDUMP_MACHDEP_LWP_NOTES
-       COREDUMP_MACHDEP_LWP_NOTES(l, ns, name);
+       COREDUMP_MACHDEP_LWP_NOTES(l, ns, d->name);
 #endif
 
-       return (0);
+ out:
+       kmem_free(d, sizeof(*d));
+       return (error);
 }
 
 static void