On Sun, Sep 03, 2017 at 10:30:00AM +0200, Nicolas Iooss wrote: > Function dax_pmd_insert_mapping() contains the following code: > > pfn_t pfn; > if (bdev_dax_pgoff(bdev, sector, size, &pgoff) != 0) > goto fallback; > /* ... */ > fallback: > trace_dax_pmd_insert_mapping_fallback(inode, vmf, length, pfn, ret); > > When the condition in the if statement fails, the function calls > trace_dax_pmd_insert_mapping_fallback() with an uninitialized pfn value. > > This issue has been found while building the kernel with clang. The > compiler reported: > > fs/dax.c:1280:6: error: variable 'pfn' is used uninitialized > whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] > if (bdev_dax_pgoff(bdev, sector, size, &pgoff) != 0) > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > fs/dax.c:1310:60: note: uninitialized use occurs here > trace_dax_pmd_insert_mapping_fallback(inode, vmf, length, pfn, ret); > ^~~ > > Signed-off-by: Nicolas Iooss <[email protected]>
Yep this looks good. Thanks for the fix. Reviewed-by: Ross Zwisler <[email protected]> > --- > fs/dax.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/dax.c b/fs/dax.c > index ab925dc6647a..20e6d76d6fff 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -1283,7 +1283,7 @@ static int dax_pmd_insert_mapping(struct vm_fault *vmf, > struct iomap *iomap, > void *ret = NULL, *kaddr; > long length = 0; > pgoff_t pgoff; > - pfn_t pfn; > + pfn_t pfn = {}; > int id; > > if (bdev_dax_pgoff(bdev, sector, size, &pgoff) != 0) > -- > 2.14.1 >
