On Tue, Nov 20, 2018 at 07:09:53AM +0000, gongchen (E) wrote:
> Hi Dear Herbert,
> 
>             Sorry to bother you , but we’ve met a problem in crypto module, 
> would you please kindly help us look into it ? Thank you very much.
> 
>              In the below function chain, scatterwalk_start() doesn't check 
> the result of sg_next(), so the kernel will crash if sg_next() returns a null 
> pointer, which is our case. (The full stack is at the end of letter)
>              
> blkcipher_walk_done()->scatterwalk_done()->scatterwalk_pagedone()->scatterwalk_start(walk,
>  sg_next(walk->sg));
>             
>             Should we add a null-pointer-check in scatterwalk_start()? Or is 
> there any process can ensure that there should be a valid sg pointer if the 
> condition (walk->offset >= walk->sg->offset + walk->sg->length) is true?
>                       
>             We are really looking forward to your reply, any information will 
> be appreciated , thanks again.

Did you apply the following patch?

commit 0868def3e4100591e7a1fdbf3eed1439cc8f7ca3
Author: Eric Biggers <ebigg...@google.com>
Date:   Mon Jul 23 10:54:57 2018 -0700

    crypto: blkcipher - fix crash flushing dcache in error path

Cheers,
-- 
Email: Herbert Xu <herb...@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

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