Module Name: src
Committed By: thorpej
Date: Tue Sep 28 14:52:22 UTC 2021
Modified Files:
src/sys/kern: kern_exec.c
Log Message:
In the exec path, multi-LWP programs dispose of their robust futexes
by calling exit_lwps(), except for the last LWP. So, dispose of that
LWP's robust futexes right before calling lwp_ctl_exit().
Fixes a "WARNING: ... : unmapped robust futex list head" message when
running bash under Linux emulation on aarch64.
Root caused and patch proposed by ryo@. I have tweaked it slightly,
just to add a comment and a KASSERT().
To generate a diff of this commit:
cvs rdiff -u -r1.506 -r1.507 src/sys/kern/kern_exec.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_exec.c
diff -u src/sys/kern/kern_exec.c:1.506 src/sys/kern/kern_exec.c:1.507
--- src/sys/kern/kern_exec.c:1.506 Fri Jun 11 12:54:22 2021
+++ src/sys/kern/kern_exec.c Tue Sep 28 14:52:22 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_exec.c,v 1.506 2021/06/11 12:54:22 martin Exp $ */
+/* $NetBSD: kern_exec.c,v 1.507 2021/09/28 14:52:22 thorpej Exp $ */
/*-
* Copyright (c) 2008, 2019, 2020 The NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.506 2021/06/11 12:54:22 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.507 2021/09/28 14:52:22 thorpej Exp $");
#include "opt_exec.h"
#include "opt_execfmt.h"
@@ -87,6 +87,7 @@ __KERNEL_RCSID(0, "$NetBSD: kern_exec.c,
#include <sys/acct.h>
#include <sys/atomic.h>
#include <sys/exec.h>
+#include <sys/futex.h>
#include <sys/ktrace.h>
#include <sys/uidinfo.h>
#include <sys/wait.h>
@@ -1204,6 +1205,16 @@ execve_runproc(struct lwp *l, struct exe
}
KDASSERT(p->p_nlwps == 1);
+ /*
+ * All of the other LWPs got rid of their robust futexes
+ * when they exited above, but we might still have some
+ * to dispose of. Do that now.
+ */
+ if (__predict_false(l->l_robust_head != 0)) {
+ KASSERT((l->l_lid & FUTEX_TID_MASK) == l->l_lid);
+ futex_release_all_lwp(l, l->l_lid);
+ }
+
/* Destroy any lwpctl info. */
if (p->p_lwpctl != NULL)
lwp_ctl_exit();
