Re: [PATCH] security/keyring: avoid pagefaults in keyring_read_iterator

2019-10-21 Thread Jarkko Sakkinen
On Fri, Oct 18, 2019 at 02:40:30PM -0400, Chris von Recklinghausen wrote: > under a debug kernel, the following circular locking dependency was observed: > > [ 5896.294840] == > [ 5896.294846] [ INFO: possible circular locking dependency detected

Re: [PATCH] security/keyring: avoid pagefaults in keyring_read_iterator

2019-10-21 Thread Chris von Recklinghausen
On 10/21/2019 10:21 AM, David Howells wrote: > Chris von Recklinghausen wrote: > >> The put_user call from keyring_read_iterator caused a page fault which >> attempts to lock mm->mmap_sem and type->lock_class (key->sem) in the reverse >> order that keyring_read_iterator did, thus causing the circu

Re: [PATCH] security/keyring: avoid pagefaults in keyring_read_iterator

2019-10-21 Thread David Howells
Chris von Recklinghausen wrote: > The put_user call from keyring_read_iterator caused a page fault which > attempts to lock mm->mmap_sem and type->lock_class (key->sem) in the reverse > order that keyring_read_iterator did, thus causing the circular locking > dependency. > > Remedy this by using

[PATCH] security/keyring: avoid pagefaults in keyring_read_iterator

2019-10-18 Thread Chris von Recklinghausen
under a debug kernel, the following circular locking dependency was observed: [ 5896.294840] == [ 5896.294846] [ INFO: possible circular locking dependency detected ] [ 5896.294852] 3.10.0-957.31.1.el7.ppc64le.debug #1 Tainted: G OE -