From: "Eric W. Biederman" <ebiederm@xmission.com>
To: linux-kernel@vger.kernel.org
Cc: Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Oleg Nesterov <oleg@redhat.com>,
Andrei Vagin <avagin@virtuozzo.com>,
Thomas Gleixner <tglx@linutronix.de>, Greg KH <greg@kroah.com>,
Andrey Vagin <avagin@openvz.org>, Serge Hallyn <serge@hallyn.com>,
Pavel Emelyanov <xemul@virtuozzo.com>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Peter Zijlstra <peterz@infradead.org>, Willy Tarreau <w@1wt.eu>,
linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
Linux Containers <containers@lists.linux-foundation.org>,
Michael Kerrisk <mtk.manpages@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"David S. Miller" <davem@davemloft.net>,
sparclinux@vger.kernel.org
Subject: [PATCH 3/7] signal/sparc: Document a conflict with SI_USER with SIGFPE
Date: Tue, 18 Jul 2017 09:06:47 -0500 [thread overview]
Message-ID: <20170718140651.15973-3-ebiederm@xmission.com> (raw)
In-Reply-To: <87o9shg7t7.fsf_-_@xmission.com>
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.
This was introduced in 2.3.41 so this mess has had a long time for
people to be able to start depending on it.
As this bug has existed for 17 years already I don't know if it is
worth fixing. It is definitely worth documenting what is going
on so that no one decides to copy this bad decision.
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
arch/sparc/include/uapi/asm/siginfo.h | 7 +++++++
arch/sparc/kernel/traps_32.c | 2 +-
arch/sparc/kernel/traps_64.c | 2 +-
3 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/sparc/include/uapi/asm/siginfo.h b/arch/sparc/include/uapi/asm/siginfo.h
index 2d9b79ccaa50..da2126e0c536 100644
--- a/arch/sparc/include/uapi/asm/siginfo.h
+++ b/arch/sparc/include/uapi/asm/siginfo.h
@@ -17,6 +17,13 @@
#define SI_NOINFO 32767 /* no information in siginfo_t */
/*
+ * SIGFPE si_codes
+ */
+#ifdef __KERNEL__
+#define FPE_FIXME (__SI_FAULT|0) /* Broken dup of SI_USER */
+#endif /* __KERNEL__ */
+
+/*
* SIGEMT si_codes
*/
#define EMT_TAGOVF (__SI_FAULT|1) /* tag overflow */
diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
index 466d4aed06c7..581cf35ee7e3 100644
--- a/arch/sparc/kernel/traps_32.c
+++ b/arch/sparc/kernel/traps_32.c
@@ -306,7 +306,7 @@ void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
info.si_errno = 0;
info.si_addr = (void __user *)pc;
info.si_trapno = 0;
- info.si_code = __SI_FAULT;
+ info.si_code = FPE_FIXME;
if ((fsr & 0x1c000) == (1 << 14)) {
if (fsr & 0x10)
info.si_code = FPE_FLTINV;
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 196ee5eb4d48..e882e128faa3 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -2258,7 +2258,7 @@ static void do_fpe_common(struct pt_regs *regs)
info.si_errno = 0;
info.si_addr = (void __user *)regs->tpc;
info.si_trapno = 0;
- info.si_code = __SI_FAULT;
+ info.si_code = FPE_FIXME;
if ((fsr & 0x1c000) == (1 << 14)) {
if (fsr & 0x10)
info.si_code = FPE_FLTINV;
--
2.10.1
next prev parent reply other threads:[~2017-07-18 14:19 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <87lgot2loq.fsf@xmission.com>
[not found] ` <87zid90vye.fsf_-_@xmission.com>
[not found] ` <20170615225426.GP31671@ZenIV.linux.org.uk>
[not found] ` <87poe4zrs1.fsf@xmission.com>
[not found] ` <CA+55aFxpv+gchzs7AYgSC8feAOV=B6mjFgBVm4Kx+83J2CNE-w@mail.gmail.com>
[not found] ` <87poe3vsa9.fsf@xmission.com>
[not found] ` <CALCETrX=SquyR8JZqHDNx=_FQKQo-0u9AxfdUwJs_hujVO2A-g@mail.gmail.com>
[not found] ` <87h8zfua59.fsf@xmission.com>
[not found] ` <CALCETrWPBn31Dye=81r2ZMainNOnDy5c_QxbU2uRjnJs0ie=Zg@mail.gmail.com>
[not found] ` <87r2yjsuwl.fsf@xmission.com>
[not found] ` <20170616191602.GA10675@1wt.eu>
2017-06-30 12:36 ` [PATCH 0/8] signal: Fix sending signals with siginfo Eric W. Biederman
2017-07-18 14:04 ` [PATCH v2 0/7] " Eric W. Biederman
2017-07-18 14:06 ` [PATCH 1/7] signal/alpha: Document a conflict with SI_USER for SIGTRAP Eric W. Biederman
2017-07-18 18:22 ` Richard Henderson
2017-07-18 14:06 ` [PATCH 2/7] signal/ia64: Document a conflict with SI_USER with SIGFPE Eric W. Biederman
2017-07-18 14:06 ` Eric W. Biederman [this message]
2017-07-18 14:06 ` [PATCH 4/7] signal/mips: " Eric W. Biederman
2017-08-07 16:18 ` Maciej W. Rozycki
2017-08-07 17:41 ` Linus Torvalds
2017-08-07 19:55 ` Ralf Baechle
2017-08-08 15:29 ` Eric W. Biederman
2017-08-08 23:19 ` Maciej W. Rozycki
2017-07-18 14:06 ` [PATCH 5/7] signal/testing: Don't look for __SI_FAULT in userspace Eric W. Biederman
2017-07-18 14:06 ` [PATCH 6/7] fcntl: Don't use ambiguous SIG_POLL si_codes Eric W. Biederman
2017-07-20 16:16 ` Oleg Nesterov
2017-07-21 2:33 ` Eric W. Biederman
2017-07-18 14:06 ` [PATCH 7/7] signal: Remove kernel interal si_code magic Eric W. Biederman
2017-07-18 16:57 ` Linus Torvalds
2017-07-18 17:27 ` Eric W. Biederman
2017-07-22 20:25 ` Simplfying copy_siginfo_to_user Eric W. Biederman
2017-07-24 17:43 ` Linus Torvalds
2017-07-24 19:01 ` Eric W. Biederman
2017-07-25 1:37 ` Al Viro
2017-07-31 16:37 ` Eric W. Biederman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170718140651.15973-3-ebiederm@xmission.com \
--to=ebiederm@xmission.com \
--cc=avagin@openvz.org \
--cc=avagin@virtuozzo.com \
--cc=containers@lists.linux-foundation.org \
--cc=davem@davemloft.net \
--cc=gorcunov@openvz.org \
--cc=greg@kroah.com \
--cc=linux-api@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mtk.manpages@gmail.com \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=serge@hallyn.com \
--cc=sparclinux@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=viro@zeniv.linux.org.uk \
--cc=w@1wt.eu \
--cc=xemul@virtuozzo.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).