From 6513e9943895ec8b9432768dc5e0422bc70b82a4 Mon Sep 17 00:00:00 2001
From: Ciro Santilli <cirosantilli@proton.me>
Date: Fri, 9 May 2025 16:27:29 +0100
Subject: [PATCH] fix .sh typo on kernel module test that accept the module as
 first argument

---
 README.adoc                                 | 14 +++++++++++---
 kernel_modules/memfile.c                    |  2 +-
 rootfs_overlay/lkmc/fops.sh                 |  2 +-
 rootfs_overlay/lkmc/memfile.sh              |  4 ++--
 rootfs_overlay/lkmc/scull.sh                |  2 +-
 rootfs_overlay/lkmc/seq_file.sh             |  2 +-
 rootfs_overlay/lkmc/seq_file_single_open.sh |  2 +-
 7 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/README.adoc b/README.adoc
index a9f42c2..bf36f36 100644
--- a/README.adoc
+++ b/README.adoc
@@ -364,15 +364,15 @@ The safe way is to fist <<rebuild-buildroot-while-running,quit QEMU>>, rebuild t
 ./run --eval-after 'insmod hello.ko'
 ....
 
-or for a slightly faster turnaround just leave it on 9p and use it from there:
+where `./build-buildroot` is required after `./build-modules` because it re-generates the root filesystem with the modules that we compiled at `./build-modules`.
+
+Alternatively, for a slightly faster turnaround just leave it on 9p and use it from there:
 
 ....
 ./build-modules
 ./run --eval-after 'insmod /mnt/9p/out_rootfs_overlay/lkmc/hello.ko'
 ....
 
-`./build-buildroot` is required after `./build-modules` because it re-generates the root filesystem with the modules that we compiled at `./build-modules`.
-
 You can see that `./build` does that as well, by running:
 
 ....
@@ -7733,6 +7733,14 @@ This example behaves the same as <<fops>>, except that the in-memory virtual fil
 * link:kernel_modules/memfile.c[]
 * link:rootfs_overlay/lkmc/memfile.sh[]
 
+TODO: this example builds but oopses with out of memory on our currently default kernel v5.9.2 when doing the big allocation at:
+
+....
+dd if=/dev/zero of="$f" bs=1k count=1M
+....
+
+It works however on kernel 6.8.12, we're not sure why. We do have a potential krealloc vs kvrealloc on version check which is a very likely reason for the issue, but it has not been investigated.
+
 [[seq-file]]
 ==== seq_file
 
diff --git a/kernel_modules/memfile.c b/kernel_modules/memfile.c
index d39c317..82f4382 100644
--- a/kernel_modules/memfile.c
+++ b/kernel_modules/memfile.c
@@ -1,4 +1,4 @@
-/* https://cirosantilli.com/linux-kernel-module-cheat#fops */
+/* https://cirosantilli.com/linux-kernel-module-cheat#memfile */
 
 #include <linux/debugfs.h>
 #include <linux/errno.h> /* EFAULT */
diff --git a/rootfs_overlay/lkmc/fops.sh b/rootfs_overlay/lkmc/fops.sh
index f53c194..155aec1 100755
--- a/rootfs_overlay/lkmc/fops.sh
+++ b/rootfs_overlay/lkmc/fops.sh
@@ -4,7 +4,7 @@ set -e
 # Setup
 f=/sys/kernel/debug/lkmc_fops
 mod="${1:-fops.ko}"
-[ $# -gt 1] && shift
+[ $# -gt 1 ] && shift
 insmod "$mod" "$@"
 
 # read
diff --git a/rootfs_overlay/lkmc/memfile.sh b/rootfs_overlay/lkmc/memfile.sh
index 3fed942..fdf63a1 100755
--- a/rootfs_overlay/lkmc/memfile.sh
+++ b/rootfs_overlay/lkmc/memfile.sh
@@ -1,5 +1,5 @@
 #!/bin/sh
-set -e
+set -eux
 
 # Helpers
 odraw() (
@@ -9,7 +9,7 @@ odraw() (
 # Setup
 f=/sys/kernel/debug/lkmc_memfile
 mod="${1:-memfile.ko}"
-[ $# -gt 1] && shift
+[ $# -gt 1 ] && shift
 insmod "$mod" "$@"
 
 # Starts off empty
diff --git a/rootfs_overlay/lkmc/scull.sh b/rootfs_overlay/lkmc/scull.sh
index 9cd1263..7b3f2da 100755
--- a/rootfs_overlay/lkmc/scull.sh
+++ b/rootfs_overlay/lkmc/scull.sh
@@ -4,7 +4,7 @@ set -eux
 name=scull
 
 mod="${1:-$name.ko}"
-[ $# -gt 1] && shift
+[ $# -gt 1 ] && shift
 insmod "$mod" "$@"
 major="$(awk "\$2==\"$name\" {print \$1}" /proc/devices)"
 
diff --git a/rootfs_overlay/lkmc/seq_file.sh b/rootfs_overlay/lkmc/seq_file.sh
index 259852c..8121b3d 100755
--- a/rootfs_overlay/lkmc/seq_file.sh
+++ b/rootfs_overlay/lkmc/seq_file.sh
@@ -2,7 +2,7 @@
 set -e
 f=/sys/kernel/debug/lkmc_seq_file
 mod="${1:-seq_file.ko}"
-[ $# -gt 1] && shift
+[ $# -gt 1 ] && shift
 insmod "$mod" "$@"
 [ "$(cat "$f")" = "$(printf '0\n1\n2\n')" ]
 [ "$(cat "$f")" = "$(printf '0\n1\n2\n')" ]
diff --git a/rootfs_overlay/lkmc/seq_file_single_open.sh b/rootfs_overlay/lkmc/seq_file_single_open.sh
index ee8c552..c6eaeb8 100755
--- a/rootfs_overlay/lkmc/seq_file_single_open.sh
+++ b/rootfs_overlay/lkmc/seq_file_single_open.sh
@@ -2,7 +2,7 @@
 set -e
 f=/sys/kernel/debug/lkmc_seq_file_single_open
 mod="${1:-seq_file_single_open.ko}"
-[ $# -gt 1] && shift
+[ $# -gt 1 ] && shift
 insmod "$mod" "$@"
 [ "$(cat "$f")" = "$(printf 'ab\ncd\n')" ]
 [ "$(dd if="$f" bs=1 count=3 skip=1)" = "$(printf "b\nc\n")" ]