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LoongArch: Fix access error when read fault on a write-only VMA 

commit efb44ff64c 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@vger.kernel.org
Fixes: 09cfefb7fa ("LoongArch: Add memory management")
Signed-off-by: Jiantao Shan <shanjiantao@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiantao Shan 2024-04-24 12:36:07 +08:00 committed by Greg Kroah-Hartman
parent 94021d1d2b
commit ba9bcc0e58
1 changed files with 2 additions and 2 deletions
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4
arch/loongarch/mm/fault.c
View File

@ -193,10 +193,10 @@ 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;
}
/*