Bug Summary

File:pr/Linux4.19_x86_64_gcc_glibc_PTH_64_DBG.OBJ/pr/tests/../../../pr/tests/switch.c
Warning:line 196, column 19
Division by zero

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name switch.c -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -fhalf-no-semantic-interposition -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/var/lib/jenkins/workspace/nss-scan-build/nspr/Linux4.19_x86_64_gcc_glibc_PTH_64_DBG.OBJ/pr/tests -fcoverage-compilation-dir=/var/lib/jenkins/workspace/nss-scan-build/nspr/Linux4.19_x86_64_gcc_glibc_PTH_64_DBG.OBJ/pr/tests -resource-dir /usr/lib/llvm-18/lib/clang/18 -U NDEBUG -D DEBUG_jenkins -D PACKAGE_NAME="" -D PACKAGE_TARNAME="" -D PACKAGE_VERSION="" -D PACKAGE_STRING="" -D PACKAGE_BUGREPORT="" -D PACKAGE_URL="" -D DEBUG=1 -D HAVE_VISIBILITY_HIDDEN_ATTRIBUTE=1 -D HAVE_VISIBILITY_PRAGMA=1 -D XP_UNIX=1 -D _GNU_SOURCE=1 -D HAVE_FCNTL_FILE_LOCKING=1 -D HAVE_POINTER_LOCALTIME_R=1 -D LINUX=1 -D HAVE_DLADDR=1 -D HAVE_GETTID=1 -D HAVE_LCHOWN=1 -D HAVE_SETPRIORITY=1 -D HAVE_STRERROR=1 -D HAVE_SYSCALL=1 -D HAVE_SECURE_GETENV=1 -D _REENTRANT=1 -D FORCE_PR_LOG -D _PR_PTHREADS -U HAVE_CVAR_BUILT_ON_SEM -I /var/lib/jenkins/workspace/nss-scan-build/nss/../dist/Linux4.19_x86_64_gcc_glibc_PTH_64_DBG.OBJ/include -I ../../../pr/include -I ../../../pr/include/private -internal-isystem /usr/lib/llvm-18/lib/clang/18/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/14/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -ferror-limit 19 -fvisibility=hidden -fgnuc-version=4.2.1 -fno-inline -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2024-05-18-082241-28900-1 -x c ../../../pr/tests/switch.c
1/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2/* This Source Code Form is subject to the terms of the Mozilla Public
3 * License, v. 2.0. If a copy of the MPL was not distributed with this
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5
6/*
7** File: switch.c
8** Description: trying to time context switches
9*/
10
11#include "prinit.h"
12#include "prcvar.h"
13#include "prmem.h"
14#include "prinrval.h"
15#include "prlock.h"
16#include "prlog.h"
17#include "prthread.h"
18#include "prprf.h"
19
20#include "plerror.h"
21#include "plgetopt.h"
22
23#include "private/pprio.h"
24
25#include <stdlib.h>
26
27#define INNER_LOOPS100 100
28#define DEFAULT_LOOPS100 100
29#define DEFAULT_THREADS10 10
30
31static PRFileDesc *debug_out = NULL((void*)0);
32static PRBool debug_mode = PR_FALSE0, verbosity = PR_FALSE0, failed = PR_FALSE0;
33
34typedef struct Shared
35{
36 PRLock *ml;
37 PRCondVar *cv;
38 PRBool twiddle;
39 PRThread *thread;
40 struct Shared *next;
41} Shared;
42
43static void Help(void)
44{
45 debug_out = PR_STDOUTPR_GetSpecialFD(PR_StandardOutput);
46
47 PR_fprintf(
48 debug_out, "Usage: >./switch [-c n] [-t n] [-d] [-v] [-G] [-C n]\n");
49 PR_fprintf(
50 debug_out, "-c n\tloops at thread level (default: %d)\n", DEFAULT_LOOPS100);
51 PR_fprintf(
52 debug_out, "-t n\tnumber of threads (default: %d)\n", DEFAULT_THREADS10);
53 PR_fprintf(debug_out, "-d\tturn on debugging output (default: FALSE)\n");
54 PR_fprintf(debug_out, "-v\tturn on verbose output (default: FALSE)\n");
55 PR_fprintf(debug_out, "-G\tglobal threads only (default: FALSE)\n");
56 PR_fprintf(debug_out, "-C n\tconcurrency setting (default: 1)\n");
57} /* Help */
58
59static void PR_CALLBACK Notified(void *arg)
60{
61 Shared *shared = (Shared*)arg;
62 PRStatus status = PR_SUCCESS;
63 while (PR_SUCCESS == status)
64 {
65 PR_Lock(shared->ml);
66 while (shared->twiddle && (PR_SUCCESS == status)) {
67 status = PR_WaitCondVar(shared->cv, PR_INTERVAL_NO_TIMEOUT0xffffffffUL);
68 }
69 if (verbosity) {
70 PR_fprintf(debug_out, "+");
71 }
72 shared->twiddle = PR_TRUE1;
73 shared->next->twiddle = PR_FALSE0;
74 PR_NotifyCondVar(shared->next->cv);
75 PR_Unlock(shared->ml);
76 }
77} /* Notified */
78
79static Shared home;
80PRIntn PR_CALLBACK Switch(PRIntn argc, char **argv)
81{
82 PLOptStatus os;
83 PRStatus status;
84 PRBool help = PR_FALSE0;
85 PRUintn concurrency = 1;
86 Shared *shared, *link;
87 PRIntervalTime timein, timeout;
88 PRThreadScope thread_scope = PR_LOCAL_THREAD;
89 PRUintn thread_count, inner_count, loop_count, average;
90 PRUintn thread_limit = DEFAULT_THREADS10, loop_limit = DEFAULT_LOOPS100;
91 PLOptState *opt = PL_CreateOptState(argc, argv, "hdvc:t:C:G");
92 while (PL_OPT_EOL != (os = PL_GetNextOpt(opt)))
1
Assuming the condition is true
→
2
←
Loop condition is true. Entering loop body
→
6
←
 Execution continues on line 92
→
7
←
Assuming the condition is true
→
8
←
Loop condition is true. Entering loop body
→
13
←
 Execution continues on line 92
→
14
←
Assuming the condition is false
→
15
←
Loop condition is false. Execution continues on line 124
→
93 {
94 if (PL_OPT_BAD == os) {
3
←
Assuming 'os' is not equal to PL_OPT_BAD
→
4
←
Taking false branch
→
9
←
Assuming 'os' is not equal to PL_OPT_BAD
→
10
←
Taking false branch
→
95 continue;
96 }
97 switch (opt->option)
5
←
Control jumps to 'case 116:' at line 107
→
11
←
Control jumps to 'case 99:' at line 104
→
98 {
99 case 'v': /* verbose mode */
100 verbosity = PR_TRUE1;
101 case 'd': /* debug mode */
102 debug_mode = PR_TRUE1;
103 break;
104 case 'c': /* loop counter */
105 loop_limit = atoi(opt->value);
12
←
Value assigned to 'loop_limit'
→
106 break;
107 case 't': /* thread limit */
108 thread_limit = atoi(opt->value);
109 break;
110 case 'C': /* Concurrency limit */
111 concurrency = atoi(opt->value);
112 break;
113 case 'G': /* global threads only */
114 thread_scope = PR_GLOBAL_THREAD;
115 break;
116 case 'h': /* help message */
117 Help();
118 help = PR_TRUE1;
119 break;
120 default:
121 break;
122 }
123 }
124 PL_DestroyOptState(opt);
125
126 if (help
15.1
'help' is 0
) {
16
←
Taking false branch
→
127 return -1;
128 }
129
130 if (PR_TRUE1 == debug_mode)
17
←
Assuming 'debug_mode' is not equal to PR_TRUE
→
18
←
Taking false branch
→
131 {
132 debug_out = PR_STDOUTPR_GetSpecialFD(PR_StandardOutput);
133 PR_fprintf(debug_out, "Test parameters\n");
134 PR_fprintf(debug_out, "\tThreads involved: %d\n", thread_limit);
135 PR_fprintf(debug_out, "\tIteration limit: %d\n", loop_limit);
136 PR_fprintf(debug_out, "\tConcurrency: %d\n", concurrency);
137 PR_fprintf(
138 debug_out, "\tThread type: %s\n",
139 (PR_GLOBAL_THREAD == thread_scope) ? "GLOBAL" : "LOCAL");
140 }
141
142 PR_SetConcurrency(concurrency);
143
144 link = &home;
145 home.ml = PR_NewLock();
146 home.cv = PR_NewCondVar(home.ml);
147 home.twiddle = PR_FALSE0;
148 home.next = NULL((void*)0);
149
150 timeout = 0;
151
152 for (thread_count = 1; thread_count <= thread_limit; ++thread_count)
19
←
Assuming 'thread_count' is > 'thread_limit'
→
20
←
Loop condition is false. Execution continues on line 172
→
153 {
154 shared = PR_NEWZAP(Shared)((Shared*)PR_Calloc(1, sizeof(Shared)));
155
156 shared->ml = home.ml;
157 shared->cv = PR_NewCondVar(home.ml);
158 shared->twiddle = PR_TRUE1;
159 shared->next = link;
160 link = shared;
161
162 shared->thread = PR_CreateThread(
163 PR_USER_THREAD, Notified, shared,
164 PR_PRIORITY_HIGH, thread_scope,
165 PR_JOINABLE_THREAD, 0);
166 PR_ASSERT(shared->thread != NULL)((shared->thread != ((void*)0))?((void)0):PR_Assert("shared->thread != NULL"
,"../../../pr/tests/switch.c",166));
167 if (NULL((void*)0) == shared->thread) {
168 failed = PR_TRUE1;
169 }
170 }
171
172 for (loop_count = 1; loop_count <= loop_limit; ++loop_count)
21
←
Assuming 'loop_count' is > 'loop_limit'
→
22
←
Loop condition is false. Execution continues on line 193
→
173 {
174 timein = PR_IntervalNow();
175 for (inner_count = 0; inner_count < INNER_LOOPS100; ++inner_count)
176 {
177 PR_Lock(home.ml);
178 home.twiddle = PR_TRUE1;
179 shared->twiddle = PR_FALSE0;
180 PR_NotifyCondVar(shared->cv);
181 while (home.twiddle)
182 {
183 status = PR_WaitCondVar(home.cv, PR_INTERVAL_NO_TIMEOUT0xffffffffUL);
184 if (PR_FAILURE == status) {
185 failed = PR_TRUE1;
186 }
187 }
188 PR_Unlock(home.ml);
189 }
190 timeout += (PR_IntervalNow() - timein);
191 }
192
193 if (debug_mode)
23
←
Assuming 'debug_mode' is not equal to 0
→
24
←
Taking true branch
→
194 {
195 average = PR_IntervalToMicroseconds(timeout)
196 / (INNER_LOOPS100 * loop_limit * thread_count);
25
←
Division by zero
197 PR_fprintf(
198 debug_out, "Average switch times %d usecs for %d threads\n",
199 average, thread_limit);
200 }
201
202 link = shared;
203 for (thread_count = 1; thread_count <= thread_limit; ++thread_count)
204 {
205 if (&home == link) {
206 break;
207 }
208 status = PR_Interrupt(link->thread);
209 if (PR_SUCCESS != status)
210 {
211 failed = PR_TRUE1;
212 if (debug_mode) {
213 PL_FPrintError(debug_out, "Failed to interrupt");
214 }
215 }
216 link = link->next;
217 }
218
219 for (thread_count = 1; thread_count <= thread_limit; ++thread_count)
220 {
221 link = shared->next;
222 status = PR_JoinThread(shared->thread);
223 if (PR_SUCCESS != status)
224 {
225 failed = PR_TRUE1;
226 if (debug_mode) {
227 PL_FPrintError(debug_out, "Failed to join");
228 }
229 }
230 PR_DestroyCondVar(shared->cv);
231 PR_DELETE(shared){ PR_Free(shared); (shared) = ((void*)0); };
232 if (&home == link) {
233 break;
234 }
235 shared = link;
236 }
237 PR_DestroyCondVar(home.cv);
238 PR_DestroyLock(home.ml);
239
240 PR_fprintf(PR_STDOUTPR_GetSpecialFD(PR_StandardOutput), ((failed) ? "FAILED\n" : "PASSED\n"));
241 return ((failed) ? 1 : 0);
242} /* Switch */
243
244int main(int argc, char **argv)
245{
246 PRIntn result;
247 PR_STDIO_INIT();
248 result = PR_Initialize(Switch, argc, argv, 0);
249 return result;
250} /* main */
251
252/* switch.c */