SIGSEGV if compiled with -fexceptions #52
Description
Hello,
there is a curious case with makepkg from Arch Linux involved.
The default config uses the following build flags:
#-- Compiler and Linker Flags
#CPPFLAGS=""
CFLAGS="-march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions \
-Wp,-D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security \
-fstack-clash-protection -fcf-protection"
CXXFLAGS="$CFLAGS -Wp,-D_GLIBCXX_ASSERTIONS"
If slurm gets compiled with said -fexceptions it will instantly segfault with SIGSEGV upon executing the binary.
Which seems odd?
-fexceptions
Enable exception handling. Generates extra code needed to propagate exceptions. For some targets, this implies GCC generates frame unwind information for all functions, which can produce significant data size overhead, although it does not affect execution. If you do not specify this option, GCC enables it by default for languages like C++ that normally require exception handling, and disables it for languages like C that do not normally require it. However, you may need to enable this option when compiling C code that needs to interoperate properly with exception handlers written in C++. You may also wish to disable this option if you are compiling older C++ programs that don’t use exception handling.
https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#index-fexceptions
So it shouldn't be the cause, as this a C based program? But somehow it is.
And maybe it's related to the various warnings from the compiler?
[1/2] Compiling C object slurm.p/slurm.c.o
In file included from ../slurm-upstream-0.4.4/slurm.c:57:
../slurm-upstream-0.4.4/src/linux.c: In function ‘get_stat’:
../slurm-upstream-0.4.4/src/linux.c:66:5: warning: ignoring return value of ‘fgets’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
66 | fgets(buffer, BUFSIZ - 1, proc_net_dev);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../slurm-upstream-0.4.4/src/linux.c:67:5: warning: ignoring return value of ‘fgets’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
67 | fgets(buffer, BUFSIZ - 1, proc_net_dev);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../slurm-upstream-0.4.4/slurm.c: In function ‘slurm_shutdown’:
../slurm-upstream-0.4.4/slurm.c:1539:5: warning: ignoring return value of ‘system’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
1539 | system("clear");
| ^~~~~~~~~~~~~~~
../slurm-upstream-0.4.4/slurm.c: In function ‘update_stat_large’:
../slurm-upstream-0.4.4/slurm.c:414:41: warning: iteration 76 invokes undefined behavior [-Waggressive-loop-optimizations]
414 | rx_speedarray[x] = rx_speedarray[x - 1];
| ~~~~~~~~~~~~~^~~~~~~
../slurm-upstream-0.4.4/slurm.c:413:33: note: within this loop
413 | for (x = GRAPH_WIDTH - 1; x >= 0; x--) {
| ~~^~~~
../slurm-upstream-0.4.4/slurm.c: In function ‘update_stat_split’:
../slurm-upstream-0.4.4/slurm.c:700:41: warning: iteration 76 invokes undefined behavior [-Waggressive-loop-optimizations]
700 | rx_speedarray[x] = rx_speedarray[x - 1];
| ~~~~~~~~~~~~~^~~~~~~
../slurm-upstream-0.4.4/slurm.c:699:38: note: within this loop
699 | for (x = GRAPHSPLIT_WIDTH - 1; x >= 0; x--) {
| ~~^~~~
../slurm-upstream-0.4.4/slurm.c: In function ‘update_stat_combined’:
../slurm-upstream-0.4.4/slurm.c:946:41: warning: iteration 76 invokes undefined behavior [-Waggressive-loop-optimizations]
946 | rx_speedarray[x] = rx_speedarray[x - 1];
| ~~~~~~~~~~~~~^~~~~~~
../slurm-upstream-0.4.4/slurm.c:945:41: note: within this loop
945 | for (x = GRAPHCOMBINED_WIDTH - 1; x >= 0; x--) {
| ~~^~~~
[2/2] Linking target slurm
In function ‘update_stat_combined’,
inlined from ‘update_stat.isra’ at ../slurm-upstream-0.4.4/slurm.c:1492:16:
../slurm-upstream-0.4.4/slurm.c:946:41: warning: iteration 76 invokes undefined behavior [-Waggressive-loop-optimizations]
946 | rx_speedarray[x] = rx_speedarray[x - 1];
| ^
../slurm-upstream-0.4.4/slurm.c:945:41: note: within this loop
945 | for (x = GRAPHCOMBINED_WIDTH - 1; x >= 0; x--) {
| ^
In function ‘update_stat_split’,
inlined from ‘update_stat.isra’ at ../slurm-upstream-0.4.4/slurm.c:1495:16:
../slurm-upstream-0.4.4/slurm.c:700:41: warning: iteration 76 invokes undefined behavior [-Waggressive-loop-optimizations]
700 | rx_speedarray[x] = rx_speedarray[x - 1];
| ^
../slurm-upstream-0.4.4/slurm.c:699:38: note: within this loop
699 | for (x = GRAPHSPLIT_WIDTH - 1; x >= 0; x--) {
| ^
In function ‘update_stat_large’,
inlined from ‘update_stat.isra’ at ../slurm-upstream-0.4.4/slurm.c:1498:16:
../slurm-upstream-0.4.4/slurm.c:414:41: warning: iteration 76 invokes undefined behavior [-Waggressive-loop-optimizations]
414 | rx_speedarray[x] = rx_speedarray[x - 1];
| ^
../slurm-upstream-0.4.4/slurm.c:413:33: note: within this loop
413 | for (x = GRAPH_WIDTH - 1; x >= 0; x--) {
| ^
In function ‘update_stat_combined’,
inlined from ‘update_stat.isra’ at ../slurm-upstream-0.4.4/slurm.c:1492:16:
../slurm-upstream-0.4.4/slurm.c:946:26: warning: ‘__builtin_memmove’ reading 308 bytes from a region of size 0 [-Wstringop-overread]
946 | rx_speedarray[x] = rx_speedarray[x - 1];
| ^
../slurm-upstream-0.4.4/slurm.h: In function ‘update_stat.isra’:
../slurm-upstream-0.4.4/slurm.h:181:7: note: at offset -4 into source object ‘rx_speedarray’ of size 308
181 | float rx_speedarray[GRAPHSPLIT_WIDTH];
| ^
In function ‘update_stat_combined’,
inlined from ‘update_stat.isra’ at ../slurm-upstream-0.4.4/slurm.c:1492:16:
../slurm-upstream-0.4.4/slurm.c:947:26: warning: ‘__builtin_memmove’ reading 308 bytes from a region of size 0 [-Wstringop-overread]
947 | tx_speedarray[x] = tx_speedarray[x - 1];
| ^
../slurm-upstream-0.4.4/slurm.h: In function ‘update_stat.isra’:
../slurm-upstream-0.4.4/slurm.h:187:7: note: at offset -4 into source object ‘tx_speedarray’ of size 308
187 | float tx_speedarray[GRAPHSPLIT_WIDTH];
| ^
In function ‘update_stat_combined’,
inlined from ‘update_stat.isra’ at ../slurm-upstream-0.4.4/slurm.c:1492:16:
../slurm-upstream-0.4.4/slurm.c:949:28: warning: ‘__builtin_memmove’ reading 3696 bytes from a region of size 0 [-Wstringop-overread]
949 | rx_graph[x][y] = rx_graph[x - 1][y];
| ^
../slurm-upstream-0.4.4/slurm.h: In function ‘update_stat.isra’:
../slurm-upstream-0.4.4/slurm.h:180:5: note: at offset -48 into source object ‘rx_graph’ of size 3696
180 | int rx_graph[GRAPHSPLIT_WIDTH][GRAPHCOMBINED_HEIGHT];
| ^
In function ‘update_stat_combined’,
inlined from ‘update_stat.isra’ at ../slurm-upstream-0.4.4/slurm.c:1492:16:
../slurm-upstream-0.4.4/slurm.c:950:28: warning: ‘__builtin_memmove’ reading 3696 bytes from a region of size 0 [-Wstringop-overread]
950 | tx_graph[x][y] = tx_graph[x - 1][y];
| ^
../slurm-upstream-0.4.4/slurm.h: In function ‘update_stat.isra’:
../slurm-upstream-0.4.4/slurm.h:186:5: note: at offset -48 into source object ‘tx_graph’ of size 3696
186 | int tx_graph[GRAPHSPLIT_WIDTH][GRAPHCOMBINED_HEIGHT];
| ^
In function ‘update_stat_split’,
inlined from ‘update_stat.isra’ at ../slurm-upstream-0.4.4/slurm.c:1495:16:
../slurm-upstream-0.4.4/slurm.c:700:26: warning: ‘__builtin_memmove’ reading 308 bytes from a region of size 0 [-Wstringop-overread]
700 | rx_speedarray[x] = rx_speedarray[x - 1];
| ^
../slurm-upstream-0.4.4/slurm.h: In function ‘update_stat.isra’:
../slurm-upstream-0.4.4/slurm.h:181:7: note: at offset -4 into source object ‘rx_speedarray’ of size 308
181 | float rx_speedarray[GRAPHSPLIT_WIDTH];
| ^
In function ‘update_stat_split’,
inlined from ‘update_stat.isra’ at ../slurm-upstream-0.4.4/slurm.c:1495:16:
../slurm-upstream-0.4.4/slurm.c:701:26: warning: ‘__builtin_memmove’ reading 308 bytes from a region of size 0 [-Wstringop-overread]
701 | tx_speedarray[x] = tx_speedarray[x - 1];
| ^
../slurm-upstream-0.4.4/slurm.h: In function ‘update_stat.isra’:
../slurm-upstream-0.4.4/slurm.h:187:7: note: at offset -4 into source object ‘tx_speedarray’ of size 308
187 | float tx_speedarray[GRAPHSPLIT_WIDTH];
| ^
In function ‘update_stat_large’,
inlined from ‘update_stat.isra’ at ../slurm-upstream-0.4.4/slurm.c:1498:16:
../slurm-upstream-0.4.4/slurm.c:414:26: warning: ‘__builtin_memmove’ reading 308 bytes from a region of size 0 [-Wstringop-overread]
414 | rx_speedarray[x] = rx_speedarray[x - 1];
| ^
../slurm-upstream-0.4.4/slurm.h: In function ‘update_stat.isra’:
../slurm-upstream-0.4.4/slurm.h:181:7: note: at offset -4 into source object ‘rx_speedarray’ of size 308
181 | float rx_speedarray[GRAPHSPLIT_WIDTH];
| ^
In function ‘update_stat_large’,
inlined from ‘update_stat.isra’ at ../slurm-upstream-0.4.4/slurm.c:1498:16:
../slurm-upstream-0.4.4/slurm.c:415:26: warning: ‘__builtin_memmove’ reading 308 bytes from a region of size 0 [-Wstringop-overread]
415 | tx_speedarray[x] = tx_speedarray[x - 1];
| ^
../slurm-upstream-0.4.4/slurm.h: In function ‘update_stat.isra’:
../slurm-upstream-0.4.4/slurm.h:187:7: note: at offset -4 into source object ‘tx_speedarray’ of size 308
187 | float tx_speedarray[GRAPHSPLIT_WIDTH];
| ^