Tue Jun 1 21:11:52 2021 UTC ()
ksyms(4): Don't skip symbol tables that are soon to be freed.

They will not actually be freed until /dev/ksyms is closed, so
continued access to them remains kosher.


(riastradh)
diff -r1.91 -r1.92 src/sys/kern/kern_ksyms.c
cvs diff -r1.91 -r1.92 src/sys/kern/kern_ksyms.c (expand / switch to unified diff)

--- src/sys/kern/kern_ksyms.c 2021/06/01 21:11:07 1.91
+++ src/sys/kern/kern_ksyms.c 2021/06/01 21:11:52 1.92
@@ -1,14 +1,14 @@ @@ -1,14 +1,14 @@
1/* $NetBSD: kern_ksyms.c,v 1.91 2021/06/01 21:11:07 riastradh Exp $ */ 1/* $NetBSD: kern_ksyms.c,v 1.92 2021/06/01 21:11:52 riastradh Exp $ */
2 2
3/*- 3/*-
4 * Copyright (c) 2008 The NetBSD Foundation, Inc. 4 * Copyright (c) 2008 The NetBSD Foundation, Inc.
5 * All rights reserved. 5 * All rights reserved.
6 * 6 *
7 * This code is derived from software developed for The NetBSD Foundation 7 * This code is derived from software developed for The NetBSD Foundation
8 * by Andrew Doran. 8 * by Andrew Doran.
9 * 9 *
10 * Redistribution and use in source and binary forms, with or without 10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions 11 * modification, are permitted provided that the following conditions
12 * are met: 12 * are met:
13 * 1. Redistributions of source code must retain the above copyright 13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer. 14 * notice, this list of conditions and the following disclaimer.
@@ -63,27 +63,27 @@ @@ -63,27 +63,27 @@
63 * struct, placed in a circular list. The first entry is the kernel 63 * struct, placed in a circular list. The first entry is the kernel
64 * symbol table. 64 * symbol table.
65 */ 65 */
66 66
67/* 67/*
68 * TODO: 68 * TODO:
69 * 69 *
70 * Add support for mmap, poll. 70 * Add support for mmap, poll.
71 * Constify tables. 71 * Constify tables.
72 * Constify db_symtab and move it to .rodata. 72 * Constify db_symtab and move it to .rodata.
73 */ 73 */
74 74
75#include <sys/cdefs.h> 75#include <sys/cdefs.h>
76__KERNEL_RCSID(0, "$NetBSD: kern_ksyms.c,v 1.91 2021/06/01 21:11:07 riastradh Exp $"); 76__KERNEL_RCSID(0, "$NetBSD: kern_ksyms.c,v 1.92 2021/06/01 21:11:52 riastradh Exp $");
77 77
78#if defined(_KERNEL) && defined(_KERNEL_OPT) 78#if defined(_KERNEL) && defined(_KERNEL_OPT)
79#include "opt_copy_symtab.h" 79#include "opt_copy_symtab.h"
80#include "opt_ddb.h" 80#include "opt_ddb.h"
81#include "opt_dtrace.h" 81#include "opt_dtrace.h"
82#endif 82#endif
83 83
84#define _KSYMS_PRIVATE 84#define _KSYMS_PRIVATE
85 85
86#include <sys/param.h> 86#include <sys/param.h>
87#include <sys/queue.h> 87#include <sys/queue.h>
88#include <sys/exec.h> 88#include <sys/exec.h>
89#include <sys/systm.h> 89#include <sys/systm.h>
@@ -1079,50 +1079,46 @@ ksymsread(dev_t dev, struct uio *uio, in @@ -1079,50 +1079,46 @@ ksymsread(dev_t dev, struct uio *uio, in
1079 error = uiomove((char *)&ksyms_hdr + off, 1079 error = uiomove((char *)&ksyms_hdr + off,
1080 sizeof(struct ksyms_hdr) - off, uio); 1080 sizeof(struct ksyms_hdr) - off, uio);
1081 if (error != 0) 1081 if (error != 0)
1082 return error; 1082 return error;
1083 } 1083 }
1084 1084
1085 /* 1085 /*
1086 * Copy out the symbol table. 1086 * Copy out the symbol table.
1087 */ 1087 */
1088 filepos = sizeof(struct ksyms_hdr); 1088 filepos = sizeof(struct ksyms_hdr);
1089 for (st = TAILQ_FIRST(&ksyms_symtabs); 1089 for (st = TAILQ_FIRST(&ksyms_symtabs);
1090 st != ksyms_last_snapshot; 1090 st != ksyms_last_snapshot;
1091 st = TAILQ_NEXT(st, sd_queue)) { 1091 st = TAILQ_NEXT(st, sd_queue)) {
1092 if (__predict_false(st->sd_gone)) 
1093 continue; 
1094 if (uio->uio_resid == 0) 1092 if (uio->uio_resid == 0)
1095 return 0; 1093 return 0;
1096 if (uio->uio_offset <= st->sd_symsize + filepos) { 1094 if (uio->uio_offset <= st->sd_symsize + filepos) {
1097 inpos = uio->uio_offset - filepos; 1095 inpos = uio->uio_offset - filepos;
1098 error = uiomove((char *)st->sd_symstart + inpos, 1096 error = uiomove((char *)st->sd_symstart + inpos,
1099 st->sd_symsize - inpos, uio); 1097 st->sd_symsize - inpos, uio);
1100 if (error != 0) 1098 if (error != 0)
1101 return error; 1099 return error;
1102 } 1100 }
1103 filepos += st->sd_symsize; 1101 filepos += st->sd_symsize;
1104 } 1102 }
1105 1103
1106 /* 1104 /*
1107 * Copy out the string table 1105 * Copy out the string table
1108 */ 1106 */
1109 KASSERT(filepos <= sizeof(struct ksyms_hdr) + 1107 KASSERT(filepos == sizeof(struct ksyms_hdr) +
1110 ksyms_hdr.kh_shdr[SYMTAB].sh_size); 1108 ksyms_hdr.kh_shdr[SYMTAB].sh_size);
1111 for (st = TAILQ_FIRST(&ksyms_symtabs); 1109 for (st = TAILQ_FIRST(&ksyms_symtabs);
1112 st != ksyms_last_snapshot; 1110 st != ksyms_last_snapshot;
1113 st = TAILQ_NEXT(st, sd_queue)) { 1111 st = TAILQ_NEXT(st, sd_queue)) {
1114 if (__predict_false(st->sd_gone)) 
1115 continue; 
1116 if (uio->uio_resid == 0) 1112 if (uio->uio_resid == 0)
1117 return 0; 1113 return 0;
1118 if (uio->uio_offset <= st->sd_strsize + filepos) { 1114 if (uio->uio_offset <= st->sd_strsize + filepos) {
1119 inpos = uio->uio_offset - filepos; 1115 inpos = uio->uio_offset - filepos;
1120 error = uiomove((char *)st->sd_strstart + inpos, 1116 error = uiomove((char *)st->sd_strstart + inpos,
1121 st->sd_strsize - inpos, uio); 1117 st->sd_strsize - inpos, uio);
1122 if (error != 0) 1118 if (error != 0)
1123 return error; 1119 return error;
1124 } 1120 }
1125 filepos += st->sd_strsize; 1121 filepos += st->sd_strsize;
1126 } 1122 }
1127 1123
1128 /* 1124 /*