Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Huacai Chen <> | Subject | [PATCH] LoongArch: Fix access error when read fault on a write-only VMA | Date | Tue, 23 Apr 2024 15:42:57 +0800 |
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From: Jiantao Shan <shanjiantao@loongson.cn>
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.
Signed-off-by: Jiantao Shan <shanjiantao@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> --- arch/loongarch/mm/fault.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/loongarch/mm/fault.c b/arch/loongarch/mm/fault.c index 1fc2f6813ea0..97b40defde06 100644 --- a/arch/loongarch/mm/fault.c +++ b/arch/loongarch/mm/fault.c @@ -202,10 +202,10 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, 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; } /* -- 2.43.0
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