On Tue, Feb 07, 2023 at 08:15:04AM -0800, Linus Torvalds wrote: > On Tue, Feb 7, 2023 at 6:06 AM Dan Carpenter <error27@xxxxxxxxx> wrote: > > > > block/blk-crypto-profile.c:382 __blk_crypto_evict_key() warn: sleeping in atomic context > > block/blk-crypto-profile.c:390 __blk_crypto_evict_key() warn: sleeping in atomic context > > Yeah, that looks very real, but doesn't really seem to be a block bug. > > __put_super() has a big comment that it's called under the sb_lock > spinlock, so it's all in atomic context, but then: > > > -> __put_super() > > -> fscrypt_destroy_keyring() > > -> fscrypt_put_master_key_activeref() > > -> fscrypt_destroy_prepared_key() > > -> fscrypt_destroy_inline_crypt_key() > > -> blk_crypto_evict_key() > > and we have a comment in __blk_crypto_evict_key() that it must be > called in "process context". > > However, the *normal* unmount sequence does all the cleanup *before* > it gets sb_lock, and calls fscrypt_destroy_keyring() in process > context, which is probably why it never triggers in practice, because > the "last put" is normally there, not in __put_super. > > Eric? Al? > > It smells like __put_super() may need to do some parts delayed, not > under sb_lock. > It's a false positive. See the comment above fscrypt_destroy_keyring(), which is meant to explain this, though I can update the comment to be clearer. If the filesystem has been mounted, then fscrypt_destroy_keyring() is called from generic_shutdown_super(), which can sleep, and the call from __put_super() is a no-op. If the filesystem has not been mounted, then the call from __put_super() is needed, but blk_crypto_evict_key() can never be executed in that case. - Eric
