From: Kees Cook <keescook@chromium.org>
To: Jens Axboe <axboe@kernel.dk>, Damien Le Moal <damien.lemoal@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>, Hannes Reinecke <hare@suse.com>,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>,
linux-next@vger.kernel.org
Subject: Re: Coverity: blkdev_zone_mgmt(): Memory - illegal accesses
Date: Mon, 18 Nov 2019 12:46:32 -0800 [thread overview]
Message-ID: <201911181233.A2AB6617E@keescook> (raw)
In-Reply-To: <201911111735.3EA3258CBC@keescook>
On Mon, Nov 11, 2019 at 05:35:00PM -0800, coverity-bot wrote:
> Hello!
>
> This is an experimental automated report about issues detected by Coverity
> from a scan of next-20191108 as part of the linux-next weekly scan project:
> https://scan.coverity.com/projects/linux-next-weekly-scan
>
> You're getting this email because you were associated with the identified
> lines of code (noted below) that were touched by recent commits:
>
> a2d6b3a2d390 ("block: Improve zone reset execution")
>
> Coverity reported the following:
>
> *** CID 1487849: Memory - illegal accesses (USE_AFTER_FREE)
> /block/blk-zoned.c: 293 in blkdev_zone_mgmt()
> 287
> 288 /* This may take a while, so be nice to others */
> 289 cond_resched();
> 290 }
> 291
> 292 ret = submit_bio_wait(bio);
> vvv CID 1487849: Memory - illegal accesses (USE_AFTER_FREE)
> vvv Calling "bio_put" dereferences freed pointer "bio".
> 293 bio_put(bio);
I don't know this area of the code very well, but looking through the
helpers here, it does seem like "bio" gets (or can be) freed before
returning from submit_bio_wait() (regardless to what the comment
says):
submit_bio_wait()
submit_bio()
generic_make_request()
generic_make_request_check()
bio_endio()
__bio_chain_endio()
bio_put()
The path passes into some error handling here, but it does seem like it
could be possible to hit both bio_put()s?
Can anyone speak to this?
-Kees
> 294
> 295 return ret;
> 296 }
> 297 EXPORT_SYMBOL_GPL(blkdev_zone_mgmt);
> 298
>
> If this is a false positive, please let us know so we can mark it as
> such, or teach the Coverity rules to be smarter. If not, please make
> sure fixes get into linux-next. :) For patches fixing this, please
> include these lines (but double-check the "Fixes" first):
>
> Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
> Addresses-Coverity-ID: 1487849 ("Memory - illegal accesses")
> Fixes: a2d6b3a2d390 ("block: Improve zone reset execution")
>
>
> Thanks for your attention!
>
> --
> Coverity-bot
--
Kees Cook
next prev parent reply other threads:[~2019-11-18 20:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-12 1:35 Coverity: blkdev_zone_mgmt(): Memory - illegal accesses coverity-bot
2019-11-18 20:46 ` Kees Cook [this message]
2019-11-19 2:57 ` Damien Le Moal
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