This is a note to let you know that I've just added the patch titled
LoongArch: Fix access error when read fault on a write-only VMA
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
loongarch-fix-access-error-when-read-fault-on-a-write-only-vma.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From efb44ff64c95340b06331fc48634b99efc9dd77c Mon Sep 17 00:00:00 2001
From: Jiantao Shan <shanjiantao@xxxxxxxxxxx>
Date: Wed, 24 Apr 2024 12:36:07 +0800
Subject: LoongArch: Fix access error when read fault on a write-only VMA
From: Jiantao Shan <shanjiantao@xxxxxxxxxxx>
commit efb44ff64c95340b06331fc48634b99efc9dd77c upstream.
As with most architectures, allow handling of read faults in VMAs that
have VM_WRITE but without VM_READ (WRITE implies READ).
Otherwise, reading before writing a write-only memory will error while
reading after writing everything is fine.
BTW, move the VM_EXEC judgement before VM_READ/VM_WRITE to make logic a
little clearer.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 09cfefb7fa70c3af01 ("LoongArch: Add memory management")
Signed-off-by: Jiantao Shan <shanjiantao@xxxxxxxxxxx>
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/loongarch/mm/fault.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/loongarch/mm/fault.c
+++ b/arch/loongarch/mm/fault.c
@@ -202,10 +202,10 @@ good_area:
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
} else {
- if (!(vma->vm_flags & VM_READ) && address != exception_era(regs))
- goto bad_area;
if (!(vma->vm_flags & VM_EXEC) && address == exception_era(regs))
goto bad_area;
+ if (!(vma->vm_flags & (VM_READ | VM_WRITE)) && address != exception_era(regs))
+ goto bad_area;
}
/*
Patches currently in stable-queue which might be from shanjiantao@xxxxxxxxxxx are
queue-6.8/loongarch-fix-access-error-when-read-fault-on-a-write-only-vma.patch
