From: Al Viro <viro@zeniv.linux.org.uk>
To: Jeff Layton <jlayton@kernel.org>
Cc: Luis Henriques <lhenriques@suse.com>,
Ilya Dryomov <idryomov@gmail.com>, Sage Weil <sage@redhat.com>,
ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] ceph: fix buffer free while holding i_ceph_lock in __ceph_setxattr()
Date: Sat, 20 Jul 2019 00:30:32 +0100 [thread overview]
Message-ID: <20190719233032.GB17978@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190719232307.GA17978@ZenIV.linux.org.uk>
On Sat, Jul 20, 2019 at 12:23:08AM +0100, Al Viro wrote:
> On Fri, Jul 19, 2019 at 07:07:49PM -0400, Jeff Layton wrote:
>
> > Al pointed out on IRC that vfree should be callable under spinlock.
>
> Al had been near-terminally low on caffeine at the time, posted
> a retraction a few minutes later and went to grab some coffee...
>
> > It
> > only sleeps if !in_interrupt(), and I think that should return true if
> > we're holding a spinlock.
>
> It can be used from RCU callbacks and all such; it *can't* be used from
> under spinlock - on non-preempt builds there's no way to recognize that.
Re original patch: looks like the sane way to handle that.
Alternatively, we could add kvfree_atomic() for use in such situations,
but I rather doubt that it's a good idea - not unless you need to free
something under a spinlock held over a large area, which is generally
a bad idea to start with...
Note that vfree_atomic() has only one caller in the entire tree,
BTW.
next prev parent reply other threads:[~2019-07-19 23:30 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-19 14:32 [PATCH 0/4] Sleeping functions in invalid context bug fixes Luis Henriques
2019-07-19 14:32 ` [PATCH 1/4] libceph: allow ceph_buffer_put() to receive a NULL ceph_buffer Luis Henriques
2019-07-19 14:32 ` [PATCH 2/4] ceph: fix buffer free while holding i_ceph_lock in __ceph_setxattr() Luis Henriques
2019-07-19 23:07 ` Jeff Layton
2019-07-19 23:23 ` Al Viro
2019-07-19 23:30 ` Al Viro [this message]
2019-07-20 0:35 ` Jeff Layton
2019-07-19 14:32 ` [PATCH 3/4] ceph: fix buffer free while holding i_ceph_lock in __ceph_build_xattrs_blob() Luis Henriques
2019-07-19 14:32 ` [PATCH 4/4] ceph: fix buffer free while holding i_ceph_lock in fill_inode() Luis Henriques
2019-07-19 15:20 ` [PATCH 0/4] Sleeping functions in invalid context bug fixes Jeff Layton
2019-07-23 10:02 ` Ilya Dryomov
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