6.8-stable review patch. If anyone has any objections, please let me know.
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From: Jiantao Shan shanjiantao@loongson.cn
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@vger.kernel.org Fixes: 09cfefb7fa70c3af01 ("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 --- 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; }
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