Messages in this thread | | | From | Justin Forbes <> | Date | Thu, 27 Jan 2022 09:34:34 -0600 | Subject | Re: linux-next 20220125 - build failure in objtool with gcc 12 |
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On Wed, Jan 26, 2022 at 4:57 PM Valdis Klētnieks <valdis.kletnieks@vt.edu> wrote: > > Fedora Rawhide shipped gcc12, which apparently includes a new warning that > causes a build failure. Apparently, it's unable to figure out that 'ptr' remains > valid on failed realloc(), and we only call realloc() again on failures...
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104069 explains (toward the end) why gcc is leaving it to be fixed in the kernel.
> CC /usr/src/linux-next/tools/objtool/exec-cmd.o > CC /usr/src/linux-next/tools/objtool/help.o > In file included from help.c:12: > In function 'xrealloc', > inlined from 'add_cmdname' at help.c:24:2: > subcmd-util.h:56:23: error: pointer 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); > | ^~~~~~~~~~~~~~~~~~ > subcmd-util.h:58:31: error: pointer 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); > | ^~~~~~~~~~~~~~~~~~ > cc1: all warnings being treated as errors > make[4]: *** [/usr/src/linux-next/tools/build/Makefile.build:97: /usr/src/linux-next/tools/objtool/help.o] Error 1 > make[3]: *** [Makefile:59: /usr/src/linux-next/tools/objtool/libsubcmd-in.o] Error 2 > make[2]: *** [Makefile:63: /usr/src/linux-next/tools/objtool/libsubcmd.a] Error 2 > make[1]: *** [Makefile:69: objtool] Error 2 > make: *** [Makefile:1405: tools/objtool] Error 2
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