forked from luck/tmp_suning_uos_patched
x86: PAT fix
Adrian Bunk noticed the following Coverity report:
> Commit e7f260a276
> (x86: PAT use reserve free memtype in mmap of /dev/mem)
> added the following gem to arch/x86/mm/pat.c:
>
> <-- snip -->
>
> ...
> int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
> unsigned long size, pgprot_t *vma_prot)
> {
> u64 offset = ((u64) pfn) << PAGE_SHIFT;
> unsigned long flags = _PAGE_CACHE_UC_MINUS;
> unsigned long ret_flags;
> ...
> ... (nothing that touches ret_flags)
> ...
> if (flags != _PAGE_CACHE_UC_MINUS) {
> retval = reserve_memtype(offset, offset + size, flags, NULL);
> } else {
> retval = reserve_memtype(offset, offset + size, -1, &ret_flags);
> }
>
> if (retval < 0)
> return 0;
>
> flags = ret_flags;
>
> if (pfn <= max_pfn_mapped &&
> ioremap_change_attr((unsigned long)__va(offset), size, flags) < 0) {
> free_memtype(offset, offset + size);
> printk(KERN_INFO
> "%s:%d /dev/mem ioremap_change_attr failed %s for %Lx-%Lx\n",
> current->comm, current->pid,
> cattr_name(flags),
> offset, offset + size);
> return 0;
> }
>
> *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
> flags);
> return 1;
> }
>
> <-- snip -->
>
> If (flags != _PAGE_CACHE_UC_MINUS) we pass garbage from the stack to
> ioremap_change_attr() and/or __pgprot().
>
> Spotted by the Coverity checker.
the fix simplifies the code as we get rid of the 'ret_flags'
complication.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
86cf02f8ea
commit
f022bfd582
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@ -510,7 +510,6 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
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{
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u64 offset = ((u64) pfn) << PAGE_SHIFT;
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unsigned long flags = _PAGE_CACHE_UC_MINUS;
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unsigned long ret_flags;
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int retval;
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if (!range_is_allowed(pfn, size))
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@ -549,14 +548,12 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
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if (flags != _PAGE_CACHE_UC_MINUS) {
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retval = reserve_memtype(offset, offset + size, flags, NULL);
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} else {
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retval = reserve_memtype(offset, offset + size, -1, &ret_flags);
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retval = reserve_memtype(offset, offset + size, -1, &flags);
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}
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if (retval < 0)
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return 0;
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flags = ret_flags;
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if (pfn <= max_pfn_mapped &&
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ioremap_change_attr((unsigned long)__va(offset), size, flags) < 0) {
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free_memtype(offset, offset + size);
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