Josh Poimboeuf b1547d3101 objtool: Detect falling through to the next function ... There are several cases in compiled C code where a function may not return at the end, and may instead fall through to the next function. That may indicate a bug in the code, or a gcc bug, or even an objtool bug. But in each case, objtool reports an unhelpful warning, something like: drivers/scsi/qla2xxx/qla_attr.o: warning: objtool: qla2x00_get_fc_host_stats()+0x0: duplicate frame pointer save drivers/scsi/qla2xxx/qla_attr.o: warning: objtool: qla2x00_get_fc_host_stats()+0x0: frame pointer state mismatch Detect this situation and print a more useful error message: drivers/scsi/qla2xxx/qla_attr.o: warning: objtool: qla2x00_get_host_fabric_name() falls through to next function qla2x00_get_starget_node_name() Also add some information about this warning and its potential causes to the documentation. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/caa4ec6c687931db805e692d4e4bf06cd87d33e6.1460729697.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>		2016-04-16 11:14:17 +02:00
..
arch/x86	x86/asm/decoder: Use explicitly signed chars	2016-03-03 16:13:00 +01:00
Documentation	objtool: Detect falling through to the next function	2016-04-16 11:14:17 +02:00
.gitignore	objtool: Add tool to perform compile-time stack metadata validation	2016-02-29 08:35:12 +01:00
arch.h	objtool: Add tool to perform compile-time stack metadata validation	2016-02-29 08:35:12 +01:00
Build	objtool: Add tool to perform compile-time stack metadata validation	2016-02-29 08:35:12 +01:00
builtin-check.c	objtool: Detect falling through to the next function	2016-04-16 11:14:17 +02:00
builtin.h	objtool: Add tool to perform compile-time stack metadata validation	2016-02-29 08:35:12 +01:00
elf.c	objtool: Add several performance improvements	2016-03-09 10:48:10 +01:00
elf.h	objtool: Add several performance improvements	2016-03-09 10:48:10 +01:00
Makefile	objtool: Compile with debugging symbols	2016-03-09 10:48:08 +01:00
objtool.c	objtool: Add tool to perform compile-time stack metadata validation	2016-02-29 08:35:12 +01:00
special.c	objtool: Add tool to perform compile-time stack metadata validation	2016-02-29 08:35:12 +01:00
special.h	objtool: Add tool to perform compile-time stack metadata validation	2016-02-29 08:35:12 +01:00
warn.h	objtool: Add tool to perform compile-time stack metadata validation	2016-02-29 08:35:12 +01:00