I’m trying to build iwlwifi module manually and for my needs.
https://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/iwlwifi-fixes.git/tree/net/wireless/
When I run Makefile as make, I get:
subcmd-util.h: In function ‘xrealloc’:
subcmd-util.h:58:31: error: pointer ‘ptr’ may be used after ‘realloc’ [-Werror=use-after-free]
58 | ret = realloc(ptr, 1);
| ^~~~~~~~~~~~~~~
subcmd-util.h:52:21: note: call to ‘realloc’ here
52 | void *ret = realloc(ptr, size);
| ^~~~~~~~~~~~~~~~~~
subcmd-util.h:56:23: error: pointer ‘ptr’ may be used after ‘realloc’ [-Werror=use-after-free]
56 | ret = realloc(ptr, size);
| ^~~~~~~~~~~~~~~~~~
subcmd-util.h:52:21: note: call to ‘realloc’ here
52 | void *ret = realloc(ptr, size);
| ^~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
make[4]: *** [/data/iwlwifi-fixes/tools/build/Makefile.build:97: /data/iwlwifi-fixes/tools/objtool/help.o] Error 1
make[3]: *** [Makefile:59: /data/iwlwifi-fixes/tools/objtool/libsubcmd-in.o] Error 2
make[2]: *** [Makefile:63: /data/iwlwifi-fixes/tools/objtool/libsubcmd.a] Error 2
make[1]: *** [Makefile:69: objtool] Error 2
make: *** [Makefile:1349: tools/objtool] Error 2
Why is it? How to fix it?
The code hitting that error is here:
https://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/iwlwifi-fixes.git/tree/tools/lib/subcmd/subcmd-util.h
It looks fine to me.
What you are seeing is a warning that your compiler may have found a use-after-free bug, but I think this is a false positive. Your build is configured to turn this warning into a hard error.
I think it will be difficult to know how to fix this without knowing more about your build setup. Are you passing any custom CFLAGS? What compiler and version are you using?
Also, here is someone asking about the same issue (in the same code) on Stack Exchange using GGC 12.1:
https://unix.stackexchange.com/questions/709671/linux-kernel-5-15-54-compilation-errors-with-gcc-12-1
This was the top result when Googling
linux "-Werror=use-after-free".I believe you can disable this warning in this file by adding a pragma after the includes (line 8):
See https://stackoverflow.com/questions/925179/selectively-remove-a-warning-message-using-gcc
Edit: If you don’t want to change the code, try disabling the use-after-free warning from the make call:
No.
gcc --version gcc (GCC) 13.2.1 20230801The goal - simply compile it for now.
If you don’t want to change the code, try disabling the use-after-free warning from the make call: