File crash-fix-memory_driver-build-kernel-5.8.patch of Package crash.24892
From: Petr Tesarik <ptesarik@suse.com>
Subject: Fix memory driver module build with kernel 5.8+
Upstream: submitted 2020-09-04
Kernel commit fe557319aa06c23cffc9346000f119547e0f289a renamed
probe_kernel_{read,write} to copy_{from,to}_kernel_nofault.
I'm also adding inline function wrapper to allow building the
module with older kernel versions.
Additionally, commit 0493cb086353e786be56010780a0b7025b5db34c
unexported probe_kernel_write(), so writing kernel memory is
no longer possible from a module.
Without this patch, build with kernel 5.8 and later fails:
kbuild/default/crash.c: In function 'crash_write':
kbuild/default/crash.c:189:12: error: implicit declaration of function 'probe_kernel_write'; did you mean 'kernel_write'? [-Werror=implicit-function-declaration]
189 | if (probe_kernel_write(vaddr, buffer, count)) {
| ^~~~~~~~~~~~~~~~~~
| kernel_write
kbuild/default/crash.c: In function 'crash_read':
kbuild/default/crash.c:225:13: error: implicit declaration of function 'probe_kernel_read'; did you mean 'kernel_read'? [-Werror=implicit-function-declaration]
225 | if (probe_kernel_read(buffer, vaddr, count)) {
| ^~~~~~~~~~~~~~~~~
| kernel_read
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
---
memory_driver/crash.c | 27 +++++++++++++++++++++++++--
1 file changed, 25 insertions(+), 2 deletions(-)
--- a/memory_driver/crash.c
+++ b/memory_driver/crash.c
@@ -25,6 +25,7 @@
*****************************************************************************/
#include <linux/module.h>
+#include <linux/version.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/init.h>
@@ -37,6 +38,22 @@
extern int page_is_ram(unsigned long);
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 8, 0)
+
+#define CAN_WRITE_KERNEL 1
+
+static inline long copy_from_kernel_nofault(void *dst, const void *src, size_t size)
+{
+ return probe_kernel_read(dst, src, size);
+}
+
+static inline long copy_to_kernel_nofault(void *dst, const void *src, size_t size)
+{
+ return probe_kernel_write(dst, src, size);
+}
+
+#endif
+
#ifdef CONFIG_S390
/*
* For swapped prefix pages get bounce buffer using xlate_dev_mem_ptr()
@@ -160,6 +177,8 @@ crash_llseek(struct file * file, loff_t
}
}
+#ifdef CAN_WRITE_KERNEL
+
static ssize_t
crash_write(struct file *file, const char *buf, size_t count, loff_t *poff)
{
@@ -186,7 +205,7 @@ crash_write(struct file *file, const cha
return -EFAULT;
}
- if (probe_kernel_write(vaddr, buffer, count)) {
+ if (copy_to_kernel_nofault(vaddr, buffer, count)) {
unmap_virtual(page);
return -EFAULT;
}
@@ -197,6 +216,8 @@ crash_write(struct file *file, const cha
return written;
}
+#endif
+
/*
* Determine the page address for an address offset value,
* get a virtual address for it, and copy it out.
@@ -222,7 +243,7 @@ crash_read(struct file *file, char *buf,
* Use bounce buffer to bypass the CONFIG_HARDENED_USERCOPY
* kernel text restriction.
*/
- if (probe_kernel_read(buffer, vaddr, count)) {
+ if (copy_from_kernel_nofault(buffer, vaddr, count)) {
unmap_virtual(page);
return -EFAULT;
}
@@ -294,7 +315,9 @@ static struct file_operations crash_fops
.owner = THIS_MODULE,
.llseek = crash_llseek,
.read = crash_read,
+#ifdef CAN_WRITE_KERNEL
.write = crash_write,
+#endif
.unlocked_ioctl = crash_ioctl,
.open = crash_open,
.release = crash_release,