Jeff Layton 945ab8f6de locks: wake any locks blocked on request before deadlock check
Andreas reported that he was seeing the tdbtorture test fail in some
cases with -EDEADLCK when it wasn't before. Some debugging showed that
deadlock detection was sometimes discovering the caller's lock request
itself in a dependency chain.

While we remove the request from the blocked_lock_hash prior to
reattempting to acquire it, any locks that are blocked on that request
will still be present in the hash and will still have their fl_blocker
pointer set to the current request.

This causes posix_locks_deadlock to find a deadlock dependency chain
when it shouldn't, as a lock request cannot block itself.

We are going to end up waking all of those blocked locks anyway when we
go to reinsert the request back into the blocked_lock_hash, so just do
it prior to checking for deadlocks. This ensures that any lock blocked
on the current request will no longer be part of any blocked request
chain.

URL: https://bugzilla.kernel.org/show_bug.cgi?id=202975
Fixes: 5946c4319ebb ("fs/locks: allow a lock request to block other requests.")
Cc: stable@vger.kernel.org
Reported-by: Andreas Schneider <asn@redhat.com>
Signed-off-by: Neil Brown <neilb@suse.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
2019-03-25 08:36:24 -04:00
2019-03-23 10:25:12 -07:00
2019-03-07 18:32:03 -08:00
2019-03-17 13:25:26 -07:00
2019-03-16 13:05:32 -07:00
2019-03-22 14:04:38 -07:00
2019-02-21 11:41:19 +00:00
2019-03-06 14:18:59 -08:00
2019-03-10 17:48:21 -07:00
2019-03-23 10:25:12 -07:00
2019-03-24 14:02:26 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Description
Linux kernel stable tree
Readme 6 GiB
Languages
C 97.5%
Assembly 1%
Shell 0.6%
Python 0.3%
Makefile 0.3%