Commit 32772c9e authored Apr 13, 2018 by Dmitry V. Levin Committed by Eric W. Biederman Apr 19, 2018

sparc: fix compat siginfo ABI regression

Starting with commit v4.14-rc1~60^2^2~1, a SIGFPE signal sent via kill
results to wrong values in si_pid and si_uid fields of compat siginfo_t.

This happens due to FPE_FIXME being defined to 0 for sparc, and at the
same time siginfo_layout() introduced by the same commit returns
SIL_FAULT for SIGFPE if si_code == SI_USER and FPE_FIXME is defined to 0.

Fix this regression by removing FPE_FIXME macro and changing all its users
to assign FPE_FLTUNK to si_code instead of FPE_FIXME.

Note that FPE_FLTUNK is a new macro introduced by commit
266da65e.

Tested with commit v4.16-11958-g16e205cf42da.

This bug was found by strace test suite.

In the discussion about FPE_FLTUNK on sparc David Miller said:
> Eric, feel free to do something similar on Sparc.

Link: https://github.com/strace/strace/issues/21


Fixes: cc731525 ("signal: Remove kernel interal si_code magic")
Fixes: 2.3.41
Cc: David Miller <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Conceptually-Acked-By: David Miller <davem@davemloft.net>
Thanks-to: Anatoly Pugachev <matorola@gmail.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

parent 5278c0e8

arch/sparc/include/uapi/asm/siginfo.h

+0 −7

Original line number	Diff line number	Diff line
		@@ -17,13 +17,6 @@

		#define SI_NOINFO 32767 /* no information in siginfo_t */

		/*
		* SIGFPE si_codes
		*/
		#ifdef __KERNEL__
		#define FPE_FIXME 0 /* Broken dup of SI_USER */
		#endif /* __KERNEL__ */

		/*
		* SIGEMT si_codes
		*/

arch/sparc/kernel/traps_32.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -307,7 +307,7 @@ 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 = FPE_FIXME;
		info.si_code = FPE_FLTUNK;
		if ((fsr & 0x1c000) == (1 << 14)) {
		if (fsr & 0x10)
		info.si_code = FPE_FLTINV;

arch/sparc/kernel/traps_64.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2372,7 +2372,7 @@ 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 = FPE_FIXME;
		info.si_code = FPE_FLTUNK;
		if ((fsr & 0x1c000) == (1 << 14)) {
		if (fsr & 0x10)
		info.si_code = FPE_FLTINV;