mm: disable CONFIG_PER_VMA_LOCK by default until its fixed6.3-15

Signed-off-by: Mike Pagano <mpagano@gentoo.org>

2 files changed, 86 insertions, 0 deletions

diff --git a/0000_README b/0000_README
index 80499d11..ac24f1fa 100644
--- a/0000_README
+++ b/0000_README
@@ -99,6 +99,10 @@ Patch:  1700_sparc-address-warray-bound-warnings.patch
 From:		https://github.com/KSPP/linux/issues/109
 Desc:		Address -Warray-bounds warnings 
 
+Patch:  1800_mm-execve-mark-stack-as-growing-down.patch
+From:   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
+Desc:   execve: always mark stack as growing down during early stack setup
+
 Patch:  2000_BT-Check-key-sizes-only-if-Secure-Simple-Pairing-enabled.patch
 From:   https://lore.kernel.org/linux-bluetooth/20190522070540.48895-1-marcel@holtmann.org/raw
 Desc:   Bluetooth: Check key sizes only when Secure Simple Pairing is enabled. See bug #686758
diff --git a/1800_mm-execve-mark-stack-as-growing-down.patch b/1800_mm-execve-mark-stack-as-growing-down.patch
new file mode 100644
index 00000000..f3da01d8
--- /dev/null
+++ b/1800_mm-execve-mark-stack-as-growing-down.patch
@@ -0,0 +1,82 @@
+From 53a70ffa22715ab23903ef9fa4f67a21ce10a759 Mon Sep 17 00:00:00 2001
+From: Linus Torvalds <torvalds@linux-foundation.org>
+Date: Sun, 2 Jul 2023 23:20:17 -0700
+Subject: execve: always mark stack as growing down during early stack setup
+
+commit f66066bc5136f25e36a2daff4896c768f18c211e upstream.
+
+While our user stacks can grow either down (all common architectures) or
+up (parisc and the ia64 register stack), the initial stack setup when we
+copy the argument and environment strings to the new stack at execve()
+time is always done by extending the stack downwards.
+
+But it turns out that in commit 8d7071af8907 ("mm: always expand the
+stack with the mmap write lock held"), as part of making the stack
+growing code more robust, 'expand_downwards()' was now made to actually
+check the vma flags:
+
+	if (!(vma->vm_flags & VM_GROWSDOWN))
+		return -EFAULT;
+
+and that meant that this execve-time stack expansion started failing on
+parisc, because on that architecture, the stack flags do not contain the
+VM_GROWSDOWN bit.
+
+At the same time the new check in expand_downwards() is clearly correct,
+and simplified the callers, so let's not remove it.
+
+The solution is instead to just codify the fact that yes, during
+execve(), the stack grows down.  This not only matches reality, it ends
+up being particularly simple: we already have special execve-time flags
+for the stack (VM_STACK_INCOMPLETE_SETUP) and use those flags to avoid
+page migration during this setup time (see vma_is_temporary_stack() and
+invalid_migration_vma()).
+
+So just add VM_GROWSDOWN to that set of temporary flags, and now our
+stack flags automatically match reality, and the parisc stack expansion
+works again.
+
+Note that the VM_STACK_INCOMPLETE_SETUP bits will be cleared when the
+stack is finalized, so we only add the extra VM_GROWSDOWN bit on
+CONFIG_STACK_GROWSUP architectures (ie parisc) rather than adding it in
+general.
+
+Link: https://lore.kernel.org/all/612eaa53-6904-6e16-67fc-394f4faa0e16@bell.net/
+Link: https://lore.kernel.org/all/5fd98a09-4792-1433-752d-029ae3545168@gmx.de/
+Fixes: 8d7071af8907 ("mm: always expand the stack with the mmap write lock held")
+Reported-by: John David Anglin <dave.anglin@bell.net>
+Reported-and-tested-by: Helge Deller <deller@gmx.de>
+Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ include/linux/mm.h | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/mm.h b/include/linux/mm.h
+index 53bec6d4297bb..e9cf8dcd4b83d 100644
+--- a/include/linux/mm.h
++++ b/include/linux/mm.h
+@@ -384,7 +384,7 @@ extern unsigned int kobjsize(const void *objp);
+ #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
+ 
+ /* Bits set in the VMA until the stack is in its final location */
+-#define VM_STACK_INCOMPLETE_SETUP	(VM_RAND_READ | VM_SEQ_READ)
++#define VM_STACK_INCOMPLETE_SETUP (VM_RAND_READ | VM_SEQ_READ | VM_STACK_EARLY)
+ 
+ #define TASK_EXEC ((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0)
+ 
+@@ -406,8 +406,10 @@ extern unsigned int kobjsize(const void *objp);
+ 
+ #ifdef CONFIG_STACK_GROWSUP
+ #define VM_STACK	VM_GROWSUP
++#define VM_STACK_EARLY	VM_GROWSDOWN
+ #else
+ #define VM_STACK	VM_GROWSDOWN
++#define VM_STACK_EARLY	0
+ #endif
+ 
+ #define VM_STACK_FLAGS	(VM_STACK | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
+-- 
+cgit 
+