linux(4): Properly build argument list for the signal handler

Provide arguments 2 and 3 if signal handler installed with SA_SIGINFO.

MFC after:		2 weeks

1 files changed, 16 insertions, 12 deletions

diff --git a/sys/amd64/linux/linux_sysvec.c b/sys/amd64/linux/linux_sysvec.c
index 4cd41b364b95..25fc8b10e903 100644
--- a/sys/amd64/linux/linux_sysvec.c
+++ b/sys/amd64/linux/linux_sysvec.c
@@ -558,13 +558,14 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	caddr_t sp;
 	struct trapframe *regs;
 	int sig, code;
-	int oonstack;
+	int oonstack, issiginfo;
 
 	td = curthread;
 	p = td->td_proc;
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 	sig = linux_translate_traps(ksi->ksi_signo, ksi->ksi_trapno);
 	psp = p->p_sigacts;
+	issiginfo = SIGISMEMBER(psp->ps_siginfo, sig);
 	code = ksi->ksi_code;
 	mtx_assert(&psp->ps_mtx, MA_OWNED);
 	regs = td->td_frame;
@@ -616,22 +617,14 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 	/* Align to 16 bytes. */
 	sfp = (struct l_rt_sigframe *)((unsigned long)sp & ~0xFul);
 
+	mtx_unlock(&psp->ps_mtx);
+	PROC_UNLOCK(p);
+
 	/* Translate the signal. */
 	sig = bsd_to_linux_signal(sig);
-
-	/* Build the argument list for the signal handler. */
-	regs->tf_rdi = sig;			/* arg 1 in %rdi */
-	regs->tf_rax = 0;
-	regs->tf_rsi = (register_t)&sfp->sf_si;	/* arg 2 in %rsi */
-	regs->tf_rdx = (register_t)&sfp->sf_uc;	/* arg 3 in %rdx */
-	regs->tf_rcx = (register_t)catcher;
-
 	/* Fill in POSIX parts. */
 	siginfo_to_lsiginfo(&ksi->ksi_info, &sf.sf_si, sig);
 
-	mtx_unlock(&psp->ps_mtx);
-	PROC_UNLOCK(p);
-
 	/* Copy the sigframe out to the user's stack. */
 	if (copyout(&sf, sfp, sizeof(*sfp)) != 0) {
 		uprintf("pid %d comm %s has trashed its stack, killing\n",
@@ -640,6 +633,17 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
 		sigexit(td, SIGILL);
 	}
 
+	/* Build the argument list for the signal handler. */
+	regs->tf_rdi = sig;			/* arg 1 in %rdi */
+	regs->tf_rax = 0;
+	if (issiginfo) {
+		regs->tf_rsi = (register_t)&sfp->sf_si;	/* arg 2 in %rsi */
+		regs->tf_rdx = (register_t)&sfp->sf_uc;	/* arg 3 in %rdx */
+	} else {
+		regs->tf_rsi = 0;
+		regs->tf_rdx = 0;
+	}
+	regs->tf_rcx = (register_t)catcher;
 	regs->tf_rsp = (long)sfp;
 	regs->tf_rip = linux_rt_sigcode;
 	regs->tf_rflags &= ~(PSL_T | PSL_D);