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From: NeilBrown <neilb@suse.com>
To: James Simmons <jsimmons@infradead.org>
Cc: Oleg Drokin <oleg.drokin@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andreas Dilger <andreas.dilger@intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Lustre Development List <lustre-devel@lists.lustre.org>
Subject: Re: [PATCH 10/10] staging: lustre: fix error deref in ll_splice_alias().
Date: Fri, 04 May 2018 10:34:51 +1000	[thread overview]
Message-ID: <87d0ycfec4.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <alpine.LFD.2.21.1805020403530.2551@casper.infradead.org>

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On Wed, May 02 2018, James Simmons wrote:

>> d_splice_alias() can return an ERR_PTR().
>> If it does while debugging is enabled, the following
>> CDEBUG() will dereference that error and crash.
>> 
>> So add appropriate checking, and provide a separate
>> debug message for the error case.
>
> Yeah!!! It fixed the issues. Thank you.

:-)
So I've made it "Reported-and-tested-by: James"

Thanks,
NeilBrown


>
> Reviewed-by: James Simmons <jsimmons@infradead.org>
>  
>> Reported-by: James Simmons <jsimmons@infradead.org>
>> Fixes: e9d4f0b9f559 ("staging: lustre: llite: use d_splice_alias for directories.")
>> Signed-off-by: NeilBrown <neilb@suse.com>
>> ---
>>  drivers/staging/lustre/lustre/llite/namei.c |    8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>> 
>> diff --git a/drivers/staging/lustre/lustre/llite/namei.c b/drivers/staging/lustre/lustre/llite/namei.c
>> index 6c9ec462eb41..24a6873d86a2 100644
>> --- a/drivers/staging/lustre/lustre/llite/namei.c
>> +++ b/drivers/staging/lustre/lustre/llite/namei.c
>> @@ -442,11 +442,15 @@ struct dentry *ll_splice_alias(struct inode *inode, struct dentry *de)
>>  	} else {
>>  		struct dentry *new = d_splice_alias(inode, de);
>>  
>> +		if (IS_ERR(new))
>> +			CDEBUG(D_DENTRY, "splice inode %p as %pd gives error %lu\n",
>> +			       inode, de, PTR_ERR(new));
>>  		if (new)
>>  			de = new;
>>  	}
>> -	CDEBUG(D_DENTRY, "Add dentry %p inode %p refc %d flags %#x\n",
>> -	       de, d_inode(de), d_count(de), de->d_flags);
>> +	if (!IS_ERR(de))
>> +		CDEBUG(D_DENTRY, "Add dentry %p inode %p refc %d flags %#x\n",
>> +		       de, d_inode(de), d_count(de), de->d_flags);
>>  	return de;
>>  }
>>  
>> 
>> 
>> 

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  reply	other threads:[~2018-05-04  0:34 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-01  3:52 [PATCH 00/10] staging: lustre: assorted improvements NeilBrown
2018-05-01  3:52 ` [PATCH 02/10] staging: lustre: make struct lu_site_bkt_data private NeilBrown
2018-05-01  4:10   ` [lustre-devel] " Dilger, Andreas
2018-05-02  3:02   ` James Simmons
2018-05-03 23:39     ` NeilBrown
2018-05-07  1:42       ` Greg Kroah-Hartman
2018-05-01  3:52 ` [PATCH 01/10] staging: lustre: ldlm: store name directly in namespace NeilBrown
2018-05-01  4:04   ` Dilger, Andreas
2018-05-02 18:11   ` James Simmons
2018-05-01  3:52 ` [PATCH 03/10] staging: lustre: lu_object: discard extra lru count NeilBrown
2018-05-01  4:19   ` Dilger, Andreas
2018-05-04  0:08     ` NeilBrown
2018-05-01  3:52 ` [PATCH 07/10] staging: lustre: llite: remove redundant lookup in dump_pgcache NeilBrown
2018-05-01  3:52 ` [PATCH 08/10] staging: lustre: move misc-device registration closer to related code NeilBrown
2018-05-02 18:12   ` James Simmons
2018-05-01  3:52 ` [PATCH 04/10] staging: lustre: lu_object: move retry logic inside htable_lookup NeilBrown
2018-05-01  8:22   ` [lustre-devel] " Dilger, Andreas
2018-05-02 18:21     ` James Simmons
2018-05-04  0:30       ` NeilBrown
2018-05-04  1:30     ` NeilBrown
2018-05-01  3:52 ` [PATCH 05/10] staging: lustre: fold lu_object_new() into lu_object_find_at() NeilBrown
2018-05-01  3:52 ` [PATCH 10/10] staging: lustre: fix error deref in ll_splice_alias() NeilBrown
2018-05-02  3:05   ` James Simmons
2018-05-04  0:34     ` NeilBrown [this message]
2018-05-01  3:52 ` [PATCH 06/10] staging: lustre: llite: use more private data in dump_pgcache NeilBrown
2018-05-01  3:52 ` [PATCH 09/10] staging: lustre: move remaining code from linux-module.c to module.c NeilBrown
2018-05-02 18:13   ` James Simmons
2018-05-07  0:54 [PATCH 00/10 - v2] staging: lustre: assorted improvements NeilBrown
2018-05-07  0:54 ` [PATCH 10/10] staging: lustre: fix error deref in ll_splice_alias() NeilBrown

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