The patch titled
Subject: proc/kcore: do not try to access unaccepted memory
has been added to the -mm mm-unstable branch. Its filename is
proc-kcore-do-not-try-to-access-unaccepted-memory.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/proc-kcore-do-not-try-to-access-unaccepted-memory.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Subject: proc/kcore: do not try to access unaccepted memory
Date: Mon, 11 Sep 2023 14:21:14 +0300
Support for unaccepted memory was added recently, refer commit
dcdfdd40fa82 ("mm: Add support for unaccepted memory"), whereby a virtual
machine may need to accept memory before it can be used.
Do not try to access unaccepted memory because it can cause the guest to
fail.
For /proc/kcore, which is read-only and does not support mmap, this means a
read of unaccepted memory will return zeros.
Link: https://lkml.kernel.org/r/20230911112114.91323-3-adrian.hunter@xxxxxxxxx
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/kcore.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/proc/kcore.c~proc-kcore-do-not-try-to-access-unaccepted-memory
+++ a/fs/proc/kcore.c
@@ -546,7 +546,8 @@ static ssize_t read_kcore_iter(struct ki
* and explicitly excluded physical ranges.
*/
if (!page || PageOffline(page) ||
- is_page_hwpoison(page) || !pfn_is_ram(pfn)) {
+ is_page_hwpoison(page) || !pfn_is_ram(pfn) ||
+ pfn_is_unaccepted_memory(pfn)) {
if (iov_iter_zero(tsz, iter) != tsz) {
ret = -EFAULT;
goto out;
_
Patches currently in -mm which might be from adrian.hunter@xxxxxxxxx are
efi-unaccepted-do-not-let-proc-vmcore-try-to-access-unaccepted-memory.patch
proc-kcore-do-not-try-to-access-unaccepted-memory.patch
