From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Henderson Subject: Re: [PATCH 1/7] signal/alpha: Document a conflict with SI_USER for SIGTRAP Date: Tue, 18 Jul 2017 08:22:52 -1000 Message-ID: References: <87o9shg7t7.fsf_-_@xmission.com> <20170718140651.15973-1-ebiederm@xmission.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170718140651.15973-1-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: "Eric W. Biederman" , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andrei Vagin , Greg KH , Linux Containers , linux-alpha-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Pavel Emelyanov , Oleg Nesterov , Matt Turner , Ivan Kokshaysky , Al Viro , Andy Lutomirski , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Cyrill Gorcunov , Michael Kerrisk , Thomas Gleixner , Linus Torvalds , Willy Tarreau , Helge Deller , Andrey Vagin List-Id: linux-api@vger.kernel.org On 07/18/2017 04:06 AM, Eric W. Biederman wrote: > Setting si_code to __SI_FAULT 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. > > Given that alpha is on it's last legs I don't know that it is worth > fixing this, but it is worth documenting what is going on so that > no one decides to copy this bad decision. > > This was introduced during the 2.5 development cycle so this > mess has had a long time for people to be able to depend upon it. > > v2: Added FPE_FIXME for alpha as Helge Deller pointed out > with his alternate patch one of the cases is SIGFPE not SIGTRAP. > > Cc: Helge Deller > Cc: Richard Henderson > Cc: Ivan Kokshaysky > Cc: Matt Turner > Cc:linux-alpha-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > History Tree:https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git > Ref: 0a635c7a84cf ("Fill in siginfo_t.") > Signed-off-by: "Eric W. Biederman" > --- > arch/alpha/include/uapi/asm/siginfo.h | 14 ++++++++++++++ > arch/alpha/kernel/traps.c | 6 +++--- > 2 files changed, 17 insertions(+), 3 deletions(-) Acked-by: Richard Henderson r~