Date: Fri, 11 Mar 2005 14:31:15 -0500 From: Stephan Uphoff <ups@tree.com> To: Sam Leffler <sam@errno.com> Cc: fs@freebsd.org Subject: Re: dirhash potential bug Message-ID: <1110569475.29804.23911.camel@palm> In-Reply-To: <4231D417.9060705@errno.com> References: <4231D417.9060705@errno.com>
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On Fri, 2005-03-11 at 12:23, Sam Leffler wrote:
> Coverity's analysis tool claims there might be a null bp dereferenced in
> ufsdirhash_lookup. Attached is a patch to add a KASSERT but it'd be
> good for someone more familiar with the code to check if a change is
> required.
>
> Sam
In my opinion the change is not required.
Not knowing how the tool works my guess is that the function pointer
um_blkatoff used in UFS_BLKATOFF makes it impossible for the tool to
prove that bp will always be non-zero at this point.
Can you replace UFS_BLKATOFF(vp, (off_t)blkoff, NULL, &bp) with
ffs_blkatoff(vp, (off_t)blkoff, NULL, &bp) and rerun the test?
Stephan
>
> ______________________________________________________________________
> ==== //depot/projects/wifi/sys/ufs/ufs/ufs_dirhash.c#3 - /usr/sam/wifi/sys/ufs/ufs/ufs_dirhash.c ====
> @@ -420,6 +420,7 @@
> if (UFS_BLKATOFF(vp, (off_t)blkoff, NULL, &bp) != 0)
> return (EJUSTRETURN);
> }
> + KASSERT(bp != NULL, ("no buf?"));
> dp = (struct direct *)(bp->b_data + (offset & bmask));
> if (dp->d_reclen == 0 || dp->d_reclen >
> DIRBLKSIZ - (offset & (DIRBLKSIZ - 1))) {
>
>
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