From c2da36fecdd1dcc8a598592a3f606b72376e5d68 Mon Sep 17 00:00:00 2001
From: Edward Tomasz Napierala <trasz@FreeBSD.org>
Date: Tue, 30 Jun 2020 16:24:28 +0000
Subject: [PATCH] Make linprocfs(5) create the /proc/<PID>/task/ directores.
 This is to silence down some Chromium assertions.

PR:		kern/240991
Analyzed by:	Alex S <iwtcex@gmail.com>
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D25256
---
 sys/compat/linprocfs/linprocfs.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/sys/compat/linprocfs/linprocfs.c b/sys/compat/linprocfs/linprocfs.c
index c441193a4991..3d6ebf9e5179 100644
--- a/sys/compat/linprocfs/linprocfs.c
+++ b/sys/compat/linprocfs/linprocfs.c
@@ -1619,6 +1619,28 @@ linprocfs_doproclimits(PFS_FILL_ARGS)
 	return (error);
 }
 
+/*
+ * The point of the following two functions is to work around
+ * an assertion in Chromium; see kern/240991 for details.
+ */
+static int
+linprocfs_dotaskattr(PFS_ATTR_ARGS)
+{
+
+	vap->va_nlink = 3;
+	return (0);
+}
+
+/*
+ * Filler function for proc/<pid>/task/.dummy
+ */
+static int
+linprocfs_dotaskdummy(PFS_FILL_ARGS)
+{
+
+	return (0);
+}
+
 /*
  * Filler function for proc/sys/kernel/random/uuid
  */
@@ -1760,6 +1782,11 @@ linprocfs_init(PFS_INIT_ARGS)
 	pfs_create_file(dir, "limits", &linprocfs_doproclimits,
 	    NULL, NULL, NULL, PFS_RD);
 
+	/* /proc/<pid>/task/... */
+	dir = pfs_create_dir(dir, "task", linprocfs_dotaskattr, NULL, NULL, 0);
+	pfs_create_file(dir, ".dummy", &linprocfs_dotaskdummy,
+	    NULL, NULL, NULL, PFS_RD);
+
 	/* /proc/scsi/... */
 	dir = pfs_create_dir(root, "scsi", NULL, NULL, NULL, 0);
 	pfs_create_file(dir, "device_info", &linprocfs_doscsidevinfo,