svn commit: r366756 - head/sys/compat/linux

[Edward Tomasz Napierala]

Author: trasz
Date: Fri Oct 16 11:23:30 2020
New Revision: 366756
URL: https://svnweb.freebsd.org/changeset/base/366756

Log:
  Set default stack size for Linux apps to 8MB.  This matches Linux'
  defaults, makes core files smaller, and fixes applications which use
  pthread_join(3) in a wrong way, namely Steam.
  
  This is based on a patch submitted by Jason Yang, which I've reworked
  to set the limit instead of only changing the value reported (which
  is enough to fix the bug for Linux pthreads, but could be confusing).
  
  PR:		248225
  Submitted by:	Jason_YH_Yang at wistron.com (earlier version)
  Analyzed by:	Alex S <iwtcex at gmail.com>
  Reviewed by:	emaste
  MFC after:	2 weeks
  Sponsored by:	The FreeBSD Foundation
  Differential Revision:	https://reviews.freebsd.org/D26778

Modified:
  head/sys/compat/linux/linux_emul.c
  head/sys/compat/linux/linux_mib.c
  head/sys/compat/linux/linux_mib.h

Modified: head/sys/compat/linux/linux_emul.c
==============================================================================
--- head/sys/compat/linux/linux_emul.c	Fri Oct 16 11:22:29 2020	(r366755)
+++ head/sys/compat/linux/linux_emul.c	Fri Oct 16 11:23:30 2020	(r366756)
@@ -115,6 +115,29 @@ linux_set_default_openfiles(struct thread *td, struct 
 	KASSERT(error == 0, ("kern_proc_setrlimit failed"));
 }
 
+/*
+ * The default stack size limit in Linux is 8MB.
+ */
+static void
+linux_set_default_stacksize(struct thread *td, struct proc *p)
+{
+	struct rlimit rlim;
+	int error;
+
+	if (linux_default_stacksize < 0)
+		return;
+
+	PROC_LOCK(p);
+	lim_rlimit_proc(p, RLIMIT_STACK, &rlim);
+	PROC_UNLOCK(p);
+	if (rlim.rlim_cur != rlim.rlim_max ||
+	    rlim.rlim_cur <= linux_default_stacksize)
+		return;
+	rlim.rlim_cur = linux_default_stacksize;
+	error = kern_proc_setrlimit(td, p, RLIMIT_STACK, &rlim);
+	KASSERT(error == 0, ("kern_proc_setrlimit failed"));
+}
+
 void
 linux_proc_init(struct thread *td, struct thread *newtd, int flags)
 {
@@ -145,6 +168,7 @@ linux_proc_init(struct thread *td, struct thread *newt
 		newtd->td_emuldata = em;
 
 		linux_set_default_openfiles(td, p);
+		linux_set_default_stacksize(td, p);
 	} else {
 		p = td->td_proc;
 

Modified: head/sys/compat/linux/linux_mib.c
==============================================================================
--- head/sys/compat/linux/linux_mib.c	Fri Oct 16 11:22:29 2020	(r366755)
+++ head/sys/compat/linux/linux_mib.c	Fri Oct 16 11:23:30 2020	(r366756)
@@ -72,6 +72,11 @@ SYSCTL_INT(_compat_linux, OID_AUTO, default_openfiles,
     &linux_default_openfiles, 0,
     "Default soft openfiles resource limit, or -1 for unlimited");
 
+int linux_default_stacksize = 8 * 1024 * 1024;
+SYSCTL_INT(_compat_linux, OID_AUTO, default_stacksize, CTLFLAG_RWTUN,
+    &linux_default_stacksize, 0,
+    "Default soft stack size resource limit, or -1 for unlimited");
+
 int linux_ignore_ip_recverr = 1;
 SYSCTL_INT(_compat_linux, OID_AUTO, ignore_ip_recverr, CTLFLAG_RWTUN,
     &linux_ignore_ip_recverr, 0, "Ignore enabling IP_RECVERR");

Modified: head/sys/compat/linux/linux_mib.h
==============================================================================
--- head/sys/compat/linux/linux_mib.h	Fri Oct 16 11:22:29 2020	(r366755)
+++ head/sys/compat/linux/linux_mib.h	Fri Oct 16 11:23:30 2020	(r366756)
@@ -64,6 +64,7 @@ int	linux_kernver(struct thread *td);
 
 extern int linux_debug;
 extern int linux_default_openfiles;
+extern int linux_default_stacksize;
 extern int linux_ignore_ip_recverr;
 extern int linux_preserve_vstatus;
 extern bool linux_map_sched_prio;