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| author | Ingo Molnar <mingo@elte.hu> | 2008-03-21 15:42:28 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-28 08:15:16 -0700 |
| commit | f022bfd58253099102218db5249220a7f4787114 (patch) | |
| tree | 21409f8c6c1fefb370b86c2b6d86d94802147d61 /arch | |
| parent | 86cf02f8eaea1b09e102e0f432fc137dc5cf4407 (diff) | |
| download | linux-stable-f022bfd58253099102218db5249220a7f4787114.tar.gz linux-stable-f022bfd58253099102218db5249220a7f4787114.tar.bz2 linux-stable-f022bfd58253099102218db5249220a7f4787114.zip | |
x86: PAT fix
Adrian Bunk noticed the following Coverity report:
> Commit e7f260a276f2c9184fe753732d834b1f6fbe9f17
> (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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/mm/pat.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index b17cdf64e41e..277446cd30b6 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -510,7 +510,6 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, { u64 offset = ((u64) pfn) << PAGE_SHIFT; unsigned long flags = _PAGE_CACHE_UC_MINUS; - unsigned long ret_flags; int retval; if (!range_is_allowed(pfn, size)) @@ -549,14 +548,12 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, if (flags != _PAGE_CACHE_UC_MINUS) { retval = reserve_memtype(offset, offset + size, flags, NULL); } else { - retval = reserve_memtype(offset, offset + size, -1, &ret_flags); + retval = reserve_memtype(offset, offset + size, -1, &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); |