The patch titled
Subject: maccess: return -ERANGE when probe_kernel_read() fails
has been removed from the -mm tree. Its filename was
maccess-return-erange-when-copy_from_kernel_nofault_allowed-fails.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: maccess: return -ERANGE when probe_kernel_read() fails
Allow the callers to distinguish a real unmapped address vs a range
that can't be probed.
Link: http://lkml.kernel.org/r/20200521152301.2587579-24-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Suggested-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/maccess.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
--- a/mm/maccess.c~maccess-return-erange-when-copy_from_kernel_nofault_allowed-fails
+++ a/mm/maccess.c
@@ -24,7 +24,7 @@ bool __weak probe_kernel_read_allowed(co
long probe_kernel_read(void *dst, const void *src, size_t size)
{
if (!probe_kernel_read_allowed(src, size))
- return -EFAULT;
+ return -ERANGE;
pagefault_disable();
probe_kernel_read_loop(dst, src, size, u64, Efault);
@@ -68,7 +68,7 @@ long strncpy_from_kernel_nofault(char *d
if (unlikely(count <= 0))
return 0;
if (!probe_kernel_read_allowed(unsafe_addr, count))
- return -EFAULT;
+ return -ERANGE;
pagefault_disable();
do {
@@ -93,7 +93,8 @@ Efault:
* @size: size of the data chunk
*
* Safely read from kernel address @src to the buffer at @dst. If a kernel
- * fault happens, handle that and return -EFAULT.
+ * fault happens, handle that and return -EFAULT. If @src is not a valid kernel
+ * address, return -ERANGE.
*
* We ensure that the copy_from_user is executed in atomic context so that
* do_page_fault() doesn't attempt to take mmap_lock. This makes
@@ -106,7 +107,7 @@ long probe_kernel_read(void *dst, const
mm_segment_t old_fs = get_fs();
if (!probe_kernel_read_allowed(src, size))
- return -EFAULT;
+ return -ERANGE;
set_fs(KERNEL_DS);
pagefault_disable();
@@ -158,8 +159,9 @@ long probe_kernel_write(void *dst, const
*
* On success, returns the length of the string INCLUDING the trailing NUL.
*
- * If access fails, returns -EFAULT (some data may have been copied
- * and the trailing NUL added).
+ * If access fails, returns -EFAULT (some data may have been copied and the
+ * trailing NUL added). If @unsafe_addr is not a valid kernel address, return
+ * -ERANGE.
*
* If @count is smaller than the length of the string, copies @count-1 bytes,
* sets the last byte of @dst buffer to NUL and returns @count.
@@ -173,7 +175,7 @@ long strncpy_from_kernel_nofault(char *d
if (unlikely(count <= 0))
return 0;
if (!probe_kernel_read_allowed(unsafe_addr, count))
- return -EFAULT;
+ return -ERANGE;
set_fs(KERNEL_DS);
pagefault_disable();
_
Patches currently in -mm which might be from hch@xxxxxx are
amdgpu-a-null-mm-does-not-mean-a-thread-is-a-kthread.patch
kernel-move-use_mm-unuse_mm-to-kthreadc.patch
kernel-move-use_mm-unuse_mm-to-kthreadc-v2.patch
kernel-better-document-the-use_mm-unuse_mm-api-contract.patch
kernel-better-document-the-use_mm-unuse_mm-api-contract-v2.patch
kernel-set-user_ds-in-kthread_use_mm.patch
