From: Andrei Vagin <avagin@gmail.com>
To: David Howells <dhowells@redhat.com>
Cc: viro@zeniv.linux.org.uk,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org, fenghua.yu@intel.com,
torvalds@linux-foundation.org, ebiederm@xmission.com,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
mszeredi@redhat.com
Subject: Re: [PATCH 21/34] kernfs, sysfs, cgroup, intel_rdt: Support fs_context [ver #12]
Date: Thu, 6 Dec 2018 09:08:23 -0800 [thread overview]
Message-ID: <20181206170822.GA15790@gmail.com> (raw)
In-Reply-To: <20181119042340.GA31532@gmail.com>
On Sun, Nov 18, 2018 at 08:23:42PM -0800, Andrei Vagin wrote:
> On Fri, Sep 21, 2018 at 05:33:01PM +0100, David Howells wrote:
> > @@ -1993,57 +2009,53 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags)
> > return ret;
> > }
> >
> > -struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
> > - struct cgroup_root *root, unsigned long magic,
> > - struct cgroup_namespace *ns)
> > +int cgroup_do_get_tree(struct fs_context *fc)
> > {
> > - struct dentry *dentry;
> > - bool new_sb;
> > + struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
> > + int ret;
> >
> > - dentry = kernfs_mount(fs_type, flags, root->kf_root, magic, &new_sb);
> > + ctx->kfc.root = ctx->root->kf_root;
> > +
> > + ret = kernfs_get_tree(fc);
> > + if (ret < 0)
> > + goto out_cgrp;
> >
> > /*
> > * In non-init cgroup namespace, instead of root cgroup's dentry,
> > * we return the dentry corresponding to the cgroupns->root_cgrp.
> > */
> > - if (!IS_ERR(dentry) && ns != &init_cgroup_ns) {
> > + if (ctx->ns != &init_cgroup_ns) {
> > struct dentry *nsdentry;
> > struct cgroup *cgrp;
> >
> > mutex_lock(&cgroup_mutex);
> > spin_lock_irq(&css_set_lock);
> >
> > - cgrp = cset_cgroup_from_root(ns->root_cset, root);
> > + cgrp = cset_cgroup_from_root(ctx->ns->root_cset, ctx->root);
> >
> > spin_unlock_irq(&css_set_lock);
> > mutex_unlock(&cgroup_mutex);
> >
> > - nsdentry = kernfs_node_dentry(cgrp->kn, dentry->d_sb);
> > - dput(dentry);
> > - dentry = nsdentry;
> > + nsdentry = kernfs_node_dentry(cgrp->kn, fc->root->d_sb);
> > + if (IS_ERR(nsdentry))
> > + return PTR_ERR(nsdentry);
> > + dput(fc->root);
> > + fc->root = nsdentry;
> > }
> >
> > - if (IS_ERR(dentry) || !new_sb)
> > - cgroup_put(&root->cgrp);
>
> I don't see where this cgroup_put() has been moved.
David, have you looked at this problem? It isn't fixed in linux-next
yet.
https://travis-ci.org/avagin/linux/jobs/463960763
Thanks,
Andrei
>
> With this patch, the next script works only once, on the second attempt
> it hangs up on mounting a cgroup file system.
>
> This is the only suspicious place in this patch what I have found.
>
> [root@fc24 ~]# cat fs-vs-cg
> d=$(mktemp -d /tmp/cg.XXXXXX)
> mkdir $d/a
> mkdir $d/b
> mount -t cgroup -o none,name=xxxx xxx $d/a
> mount -t cgroup -o none,name=xxxx xxx $d/b
> umount $d/a
> umount $d/b
>
> [root@fc24 ~]# unshare -m --propagation private bash -x fs-vs-cg
> ++ mktemp -d /tmp/cg.XXXXXX
> + d=/tmp/cg.yUfagS
> + mkdir /tmp/cg.yUfagS/a
> + mkdir /tmp/cg.yUfagS/b
> + mount -t cgroup -o none,name=xxxx xxx /tmp/cg.yUfagS/a
> + mount -t cgroup -o none,name=xxxx xxx /tmp/cg.yUfagS/b
> + umount /tmp/cg.yUfagS/a
> + umount /tmp/cg.yUfagS/b
> [root@fc24 ~]# unshare -m --propagation private bash -x fs-vs-cg
> ++ mktemp -d /tmp/cg.XXXXXX
> + d=/tmp/cg.ippWUn
> + mkdir /tmp/cg.ippWUn/a
> + mkdir /tmp/cg.ippWUn/b
> + mount -t cgroup -o none,name=xxxx xxx /tmp/cg.ippWUn/a
> ^Z
> [1]+ Stopped unshare -m --propagation private bash -x fs-vs-cg
>
> [root@fc24 ~]# ps
> PID TTY TIME CMD
> 556 pts/0 00:00:00 bash
> 591 pts/0 00:00:00 bash
> 595 pts/0 00:00:00 mount
> 596 pts/0 00:00:00 ps
>
> [root@fc24 ~]# bg
> [1]+ unshare -m --propagation private bash -x fs-vs-cg &
>
> [root@fc24 ~]# cat /proc/595/stack
> [<0>] msleep+0x38/0x40
> [<0>] cgroup1_get_tree+0x4e1/0x72c
> [<0>] vfs_get_tree+0x5e/0x140
> [<0>] do_mount+0x326/0xc70
> [<0>] ksys_mount+0xba/0xd0
> [<0>] __x64_sys_mount+0x21/0x30
> [<0>] do_syscall_64+0x60/0x210
> [<0>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
> [<0>] 0xffffffffffffffff
>
next prev parent reply other threads:[~2018-12-06 17:08 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-21 16:30 [PATCH 00/34] VFS: Introduce filesystem context [ver #12] David Howells
2018-09-21 16:30 ` [PATCH 01/34] vfs: syscall: Add open_tree(2) to reference or clone a mount " David Howells
2018-10-21 16:41 ` Eric W. Biederman
2018-09-21 16:30 ` [PATCH 02/34] vfs: syscall: Add move_mount(2) to move mounts around " David Howells
2018-09-21 16:30 ` [PATCH 03/34] teach move_mount(2) to work with OPEN_TREE_CLONE " David Howells
2018-10-05 18:24 ` Alan Jenkins
2018-10-07 10:48 ` Alan Jenkins
2018-10-07 19:20 ` Alan Jenkins
2018-10-10 12:36 ` David Howells
2018-10-12 14:22 ` Alan Jenkins
2018-10-12 14:54 ` David Howells
2018-10-12 14:57 ` Alan Jenkins
2018-10-11 9:17 ` David Howells
2018-10-11 11:48 ` Alan Jenkins
2018-10-11 13:10 ` David Howells
2018-10-11 12:14 ` David Howells
2018-10-11 12:23 ` Alan Jenkins
2018-10-11 15:33 ` David Howells
2018-10-11 18:38 ` Eric W. Biederman
2018-10-11 20:17 ` David Howells
2018-10-13 6:06 ` Al Viro
2018-10-17 17:45 ` Alan Jenkins
2018-10-18 20:09 ` David Howells
2018-10-18 20:58 ` David Howells
2018-10-19 11:57 ` David Howells
2018-10-19 13:37 ` David Howells
2018-10-19 17:35 ` Alan Jenkins
2018-10-19 21:35 ` David Howells
2018-10-19 21:40 ` David Howells
2018-10-19 22:36 ` David Howells
2018-10-20 5:25 ` Al Viro
2018-10-20 11:06 ` Alan Jenkins
2018-10-20 11:48 ` Al Viro
2018-10-20 12:26 ` Al Viro
2018-10-21 0:40 ` David Howells
2018-10-10 11:56 ` David Howells
2018-10-10 12:31 ` David Howells
2018-10-10 12:39 ` Alan Jenkins
2018-10-10 12:50 ` David Howells
2018-10-10 13:02 ` David Howells
2018-10-10 13:06 ` Alan Jenkins
2018-10-21 16:57 ` Eric W. Biederman
2018-10-23 11:19 ` Alan Jenkins
2018-10-23 16:22 ` Al Viro
2018-09-21 16:30 ` [PATCH 04/34] vfs: Suppress MS_* flag defs within the kernel unless explicitly enabled " David Howells
2018-09-21 16:30 ` [PATCH 05/34] vfs: Introduce the basic header for the new mount API's filesystem context " David Howells
2018-09-21 16:30 ` [PATCH 06/34] vfs: Introduce logging functions " David Howells
2018-09-21 16:31 ` [PATCH 07/34] vfs: Add configuration parser helpers " David Howells
2019-03-14 7:46 ` Geert Uytterhoeven
2019-03-14 10:27 ` David Howells
2019-03-14 10:49 ` Geert Uytterhoeven
2018-09-21 16:31 ` [PATCH 08/34] vfs: Add LSM hooks for the new mount API " David Howells
2018-09-21 16:31 ` [PATCH 09/34] vfs: Put security flags into the fs_context struct " David Howells
2018-09-21 16:31 ` [PATCH 10/34] selinux: Implement the new mount API LSM hooks " David Howells
2018-09-21 16:31 ` [PATCH 11/34] smack: Implement filesystem context security " David Howells
2018-09-21 16:31 ` [PATCH 12/34] apparmor: Implement security hooks for the new mount API " David Howells
2018-09-21 16:31 ` [PATCH 13/34] tomoyo: " David Howells
2018-09-21 16:32 ` [PATCH 14/34] vfs: Separate changing mount flags full remount " David Howells
2018-09-21 16:32 ` [PATCH 15/34] vfs: Implement a filesystem superblock creation/configuration context " David Howells
2018-09-21 16:32 ` [PATCH 16/34] vfs: Remove unused code after filesystem context changes " David Howells
2018-09-21 16:32 ` [PATCH 17/34] procfs: Move proc_fill_super() to fs/proc/root.c " David Howells
2018-09-21 16:32 ` [PATCH 18/34] proc: Add fs_context support to procfs " David Howells
2018-09-21 16:32 ` [PATCH 19/34] ipc: Convert mqueue fs to fs_context " David Howells
2018-09-21 16:32 ` [PATCH 20/34] cpuset: Use " David Howells
2018-09-21 16:33 ` [PATCH 21/34] kernfs, sysfs, cgroup, intel_rdt: Support " David Howells
2018-11-19 4:23 ` Andrei Vagin
2018-12-06 17:08 ` Andrei Vagin [this message]
2018-09-21 16:33 ` [PATCH 22/34] hugetlbfs: Convert to " David Howells
2018-09-21 16:33 ` [PATCH 23/34] vfs: Remove kern_mount_data() " David Howells
2018-09-21 16:33 ` [PATCH 24/34] vfs: Provide documentation for new mount API " David Howells
2018-09-21 16:33 ` [PATCH 25/34] Make anon_inodes unconditional " David Howells
2018-09-21 16:33 ` [PATCH 26/34] vfs: syscall: Add fsopen() to prepare for superblock creation " David Howells
2018-09-21 16:33 ` [PATCH 27/34] vfs: Implement logging through fs_context " David Howells
2018-09-21 16:33 ` [PATCH 28/34] vfs: Add some logging to the core users of the fs_context log " David Howells
2018-09-21 16:34 ` [PATCH 29/34] vfs: syscall: Add fsconfig() for configuring and managing a context " David Howells
2018-09-21 16:34 ` [PATCH 30/34] vfs: syscall: Add fsmount() to create a mount for a superblock " David Howells
2018-09-21 16:34 ` [PATCH 31/34] vfs: syscall: Add fspick() to select a superblock for reconfiguration " David Howells
2018-10-12 14:49 ` Alan Jenkins
2018-10-13 6:11 ` Al Viro
2018-10-13 9:45 ` Alan Jenkins
2018-10-13 23:04 ` Andy Lutomirski
2018-10-17 13:15 ` David Howells
2018-10-17 13:20 ` David Howells
2018-10-17 14:31 ` Alan Jenkins
2018-10-17 14:35 ` Eric W. Biederman
2018-10-17 14:55 ` Alan Jenkins
2018-10-17 15:24 ` David Howells
2018-10-17 15:38 ` Eric W. Biederman
2018-10-17 15:45 ` David Howells
2018-10-17 17:41 ` Alan Jenkins
2018-10-17 21:20 ` David Howells
2018-10-17 22:13 ` Alan Jenkins
2018-09-21 16:34 ` [PATCH 32/34] afs: Add fs_context support " David Howells
2018-09-21 16:34 ` [PATCH 33/34] afs: Use fs_context to pass parameters over automount " David Howells
2018-09-21 16:34 ` [PATCH 34/34] vfs: Add a sample program for the new mount API " David Howells
2018-12-17 14:12 ` Anders Roxell
2018-12-20 16:36 ` David Howells
2018-10-04 18:37 ` [PATCH 00/34] VFS: Introduce filesystem context " Eric W. Biederman
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