Josh Poimboeuf 799647ddb4 objtool: Add more robust signal error handling, detect and warn about stack overflows
When the kernel build fails due to an objtool segfault, the error
message is a bit obtuse and confusing:

  make[5]: *** [scripts/Makefile.build:503: drivers/scsi/qla2xxx/qla2xxx.o] Error 139
                                                                            ^^^^^^^^^
  make[5]: *** Deleting file 'drivers/scsi/qla2xxx/qla2xxx.o'
  make[4]: *** [scripts/Makefile.build:556: drivers/scsi/qla2xxx] Error 2
  make[3]: *** [scripts/Makefile.build:556: drivers/scsi] Error 2
  make[2]: *** [scripts/Makefile.build:556: drivers] Error 2
  make[1]: *** [/home/jpoimboe/git/linux/Makefile:2013: .] Error 2
  make: *** [Makefile:248: __sub-make] Error 2

Add a signal handler to objtool which prints an error message like if
the local stack has overflown (for which there's a chance as objtool
makes heavy use of recursion):

  drivers/scsi/qla2xxx/qla2xxx.o: error: SIGSEGV: objtool stack overflow!

or:

  drivers/scsi/qla2xxx/qla2xxx.o: error: SIGSEGV: objtool crash!

Also, re-raise the signal so the core dump still gets triggered.

[ mingo: Applied a build fix, added more comments and prettified the code. ]

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Alexandre Chartre <alexandre.chartre@oracle.com>
Cc: David Laight <david.laight.linux@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/mi4tihk4dbncn7belrhp6ooudhpw4vdggerktu5333w3gqf3uf@vqlhc3y667mg
2025-12-03 19:42:37 +01:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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