Messages in this thread |  | | Date | Sat, 3 Jun 2006 14:16:57 -0700 | | From | Joel Becker <> | | Subject | Re: [PATCH] ocfs2: dereference before NULL check in ocfs2_direct_IO_get_blocks() |
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On Sat, Jun 03, 2006 at 11:15:58PM +0400, Alexey Dobriyan wrote: > On Sat, Jun 03, 2006 at 11:34:39AM -0400, Florin Malita wrote: > > 'bh_result' & 'inode' are explicitly checked against NULL so they > > shouldn't be dereferenced prior to that. > > > > Coverity ID: 1273, 1274. > > AFAICS, the patch is BS, as usual with this type of patches. > > Can "inode" and "bh_result" be NULL here? I bet they can't.
This is a common result of this sort of scan. The scan merely provides good information, not a perfect patch. There are two possibilities:
1) The scan is right, and the dereference is dangerous. The patch is correct. 2) The dereference is not dangerous ("can't happen"), and the later check for NULL is spurious. A correct patch would merely remove the check.
This is clearly a case of (2), but I bet that (1) is seen just as often.
Joel
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Joel Becker Principal Software Developer Oracle E-mail: joel.becker@oracle.com Phone: (650) 506-8127 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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