linux_dsm_epyc7002/arch/parisc
Eric W. Biederman b5daf2b9d1 signal/parisc: Document a conflict with SI_USER with SIGFPE
Setting si_code to 0 results in a userspace seeing an si_code of 0.
This is the same si_code as SI_USER.  Posix and common sense requires
that SI_USER not be a signal specific si_code.  As such this use of 0
for the si_code is a pretty horribly broken ABI.

Further use of si_code == 0 guaranteed that copy_siginfo_to_user saw a
value of __SI_KILL and now sees a value of SIL_KILL with the result
that uid and pid fields are copied and which might copying the si_addr
field by accident but certainly not by design.  Making this a very
flakey implementation.

Utilizing FPE_FIXME siginfo_layout will now return SIL_FAULT and the
appropriate fields will reliably be copied.

This bug is 13 years old and parsic machines are no longer being built
so I don't know if it possible or worth fixing it.  But it is at least
worth documenting this so other architectures don't make the same
mistake.

Possible ABI fixes includee:
  - Send the signal without siginfo
  - Don't generate a signal
  - Possibly assign and use an appropriate si_code
  - Don't handle cases which can't happen

Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Ref: 313c01d3e3fd ("[PATCH] PA-RISC update for 2.6.0")
Histroy Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-01-12 14:21:03 -06:00
..
boot parisc: Fix indenting in puts() 2017-12-17 21:06:25 +01:00
configs net: Remove CONFIG_NETFILTER_DEBUG and _ASSERT() macros. 2017-09-04 13:25:20 +02:00
include signal/parisc: Document a conflict with SI_USER with SIGFPE 2018-01-12 14:21:03 -06:00
kernel signal/parisc: Document a conflict with SI_USER with SIGFPE 2018-01-12 14:21:03 -06:00
lib parisc: remove duplicate includes 2017-12-17 21:06:25 +01:00
math-emu License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mm License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
oprofile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
defpalo.conf parisc: switch to gzip-compressed vmlinuz kernel 2013-07-09 22:09:20 +02:00
install.sh parisc: make "make install" not depend on vmlinux 2013-11-07 22:28:06 +01:00
Kconfig arch: Fix duplicates in Kconfig for parisc and sparc 2017-11-17 15:27:54 +01:00
Kconfig.debug License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile parisc: Pass endianness info to sparse 2017-11-17 15:27:33 +01:00
nm