From: Eric Biggers <ebiggers@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-block@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
linux-fscrypt@vger.kernel.org,
Nathan Huckleberry <nhuck@google.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v2 2/4] blk-crypto: make blk_crypto_evict_key() more robust
Date: Wed, 15 Mar 2023 11:26:58 -0700 [thread overview]
Message-ID: <20230315182658.GB975@sol.localdomain> (raw)
In-Reply-To: <ZBHw8DteTQq6p97i@infradead.org>
On Wed, Mar 15, 2023 at 09:23:12AM -0700, Christoph Hellwig wrote:
> On Wed, Mar 08, 2023 at 11:36:43AM -0800, Eric Biggers wrote:
> > const struct blk_crypto_key *key)
> > @@ -389,22 +377,22 @@ int __blk_crypto_evict_key(struct blk_crypto_profile *profile,
> >
> > blk_crypto_hw_enter(profile);
> > slot = blk_crypto_find_keyslot(profile, key);
> > + if (slot) {
>
> Isn't !slot also an error condition that we should warn on?
No, definitely not. Keys are not guaranteed to be in a keyslot. I'll add a
comment here.
>
> > + if (WARN_ON_ONCE(atomic_read(&slot->slot_refs) != 0)) {
> > + /* BUG: key is still in use by I/O */
> > + err = -EBUSY;
>
> Either way two gotos to jump forward for the error case would improve
> the readability of the code a fair bit I think.
I slightly prefer it without the gotos, but sure I'll do it that way.
> > + } else {
> > + err = profile->ll_ops.keyslot_evict(
> > + profile, key,
> > + blk_crypto_keyslot_index(slot));
> > + }
> > + /*
> > + * Callers may free the key even on error, so unlink the key
> > + * from the hash table and clear slot->key even on error.
> > + */
> > + hlist_del(&slot->hash_node);
> > + slot->key = NULL;
> > }
> > blk_crypto_hw_exit(profile);
> > return err;
>
> Also given your above accurate description of the calling context,
> what is the point of even returning an error here vs just logging
> an error message?
Yes, I was thinking about that too. I'll add a patch that makes
blk_crypto_evict_key() log errors and return void.
- Eric
next prev parent reply other threads:[~2023-03-15 18:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-08 19:36 [PATCH v2 0/4] Fix blk-crypto keyslot race condition Eric Biggers
2023-03-08 19:36 ` [PATCH v2 1/4] blk-mq: release crypto keyslot before reporting I/O complete Eric Biggers
2023-03-13 21:26 ` Nathan Huckleberry
2023-03-14 18:20 ` Eric Biggers
2023-03-15 16:18 ` Christoph Hellwig
2023-03-15 16:19 ` Christoph Hellwig
2023-03-08 19:36 ` [PATCH v2 2/4] blk-crypto: make blk_crypto_evict_key() more robust Eric Biggers
2023-03-15 16:23 ` Christoph Hellwig
2023-03-15 18:26 ` Eric Biggers [this message]
2023-03-08 19:36 ` [PATCH v2 3/4] blk-crypto: remove blk_crypto_insert_cloned_request() Eric Biggers
2023-03-15 16:24 ` Christoph Hellwig
2023-03-15 18:27 ` Eric Biggers
2023-03-08 19:36 ` [PATCH v2 4/4] blk-crypto: drop the NULL check from blk_crypto_put_keyslot() Eric Biggers
2023-03-15 16:24 ` Christoph Hellwig
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