From: Vitaly Mayatskikh <vmayatsk@redhat.com>
Date: Tue, 10 Feb 2009 13:59:32 +0100
Subject: [x86-64] fix int $0x80 -ENOSYS return
Message-id: m3ocxav45n.wl%vmayatsk@redhat.com
O-Subject: [RHEL-5.4 patch] bz481682 x86-64: fix int $0x80 -ENOSYS return
Bugzilla: 481682
RH-Acked-by: Prarit Bhargava <prarit@redhat.com>
RH-Acked-by: Roland McGrath <roland@redhat.com>

Description:
============
Utrace update for RHEL-5.2 contains patch backported from upstream
commit 48ee679a02406c65ced67c3951ad19744eb21083. This commit has a
regression: if int 0x80 receives invalid syscall number (> NR_syscalls)
and it's not traced and auditd was disabled across reboot, int 0x80
returns syscall number instead of -ENOSYS.

Upstream status:
================
commit 	c09249f8d1b84344eca882547afdbffee8c09d14

Test status:
============
Tested ok with reproducer.

diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S
index 7a4b2bc..8321e2a 100644
--- a/arch/x86_64/ia32/ia32entry.S
+++ b/arch/x86_64/ia32/ia32entry.S
@@ -328,9 +328,9 @@ ENTRY(ia32_syscall)
 	orl   $TS_COMPAT,threadinfo_status(%r10)
 	testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%r10)
 	jnz ia32_tracesys
-ia32_do_syscall:	
 	cmpl $(IA32_NR_syscalls-1),%eax
-	ja  int_ret_from_sys_call	/* ia32_tracesys has set RAX(%rsp) */
+	ja ia32_badsys
+ia32_do_call:	
 	IA32_ARG_FIXUP
 	call *ia32_sys_call_table(,%rax,8) # xxx: rip relative
 ia32_sysret:
@@ -344,7 +344,9 @@ ia32_tracesys:
 	call syscall_trace_enter
 	LOAD_ARGS32 ARGOFFSET  /* reload args from stack in case ptrace changed it */
 	RESTORE_REST
-	jmp ia32_do_syscall
+	cmpl $(IA32_NR_syscalls-1),%eax
+	ja  int_ret_from_sys_call	/* ia32_tracesys has set RAX(%rsp) */
+	jmp ia32_do_call
 END(ia32_syscall)
 
 ia32_badsys: