I’m curious how did you make ceph_fs_debugfs_init fail
Yan, Zheng
> On 9 Feb 2018, at 20:40, Chengguang Xu <cgxu519@xxxxxxxxxx> wrote:
>
> When failing from ceph_fs_debugfs_init() in ceph_real_mount(),
> there is lack of dput of root_dentry and it causes slab errors,
> so change the calling order of ceph_fs_debugfs_init() and
> open_root_dentry() and do some cleanups to avoid this issue.
>
> Detail error messages:
> =============================================================================
> BUG ceph_inode_info (Not tainted): Objects remaining in ceph_inode_info on __kmem_cache_shutdown()
> -----------------------------------------------------------------------------
> Disabling lock debugging due to kernel taint
> INFO: Slab 0x000000001037cfd2 objects=23 used=1 fp=0x000000006c0dc265 flags=0x2fffff80008100
> CPU: 0 PID: 27086 Comm: rmmod Tainted: G B 4.15.0-rc8+ #7
> Hardware name: Fedora Project OpenStack Nova, BIOS seabios-1.7.5-11.el7 04/01/2014
> Call Trace:
> dump_stack+0x5c/0x7c
> slab_err+0xb4/0xe0
> ? on_each_cpu_mask+0x24/0x60
> ? on_each_cpu_cond+0xad/0x140
> ? __kmalloc+0x1be/0x1f0
> ? __kmem_cache_shutdown+0x175/0x3c0
> __kmem_cache_shutdown+0x196/0x3c0
> shutdown_cache+0x13/0x1a0
> kmem_cache_destroy+0x1e4/0x220
> destroy_caches+0x16/0x46 [ceph]
> SyS_delete_module+0x168/0x240
> ? exit_to_usermode_loop+0x6e/0x93
> entry_SYSCALL_64_fastpath+0x20/0x83
> RIP: 0033:0x7f8650f87c27
> RSP: 002b:00007ffda546ff88 EFLAGS: 00000206
> INFO: Object 0x00000000568b3053 @offset=0
> kmem_cache_destroy ceph_inode_info: Slab cache still has objects
> CPU: 0 PID: 27086 Comm: rmmod Tainted: G B 4.15.0-rc8+ #7
> Hardware name: Fedora Project OpenStack Nova, BIOS seabios-1.7.5-11.el7 04/01/2014
> Call Trace:
> dump_stack+0x5c/0x7c
> kmem_cache_destroy+0x203/0x220
> destroy_caches+0x16/0x46 [ceph]
> SyS_delete_module+0x168/0x240
> ? exit_to_usermode_loop+0x6e/0x93
> entry_SYSCALL_64_fastpath+0x20/0x83
> RIP: 0033:0x7f8650f87c27
> RSP: 002b:00007ffda546ff88 EFLAGS: 00000206
> =============================================================================
> BUG ceph_dentry_info (Tainted: G B ): Objects remaining in ceph_dentry_info on __kmem_cache_shutdown()
> -----------------------------------------------------------------------------
> INFO: Slab 0x00000000aabb3f88 objects=51 used=1 fp=0x000000002436421a flags=0x2fffff80000100
> CPU: 0 PID: 27086 Comm: rmmod Tainted: G B 4.15.0-rc8+ #7
> Hardware name: Fedora Project OpenStack Nova, BIOS seabios-1.7.5-11.el7 04/01/2014
> Call Trace:
> dump_stack+0x5c/0x7c
> slab_err+0xb4/0xe0
> ? on_each_cpu_cond+0xad/0x140
> ? __kmalloc+0x1be/0x1f0
> ? __kmem_cache_shutdown+0x175/0x3c0
> __kmem_cache_shutdown+0x196/0x3c0
> shutdown_cache+0x13/0x1a0
> kmem_cache_destroy+0x1e4/0x220
> destroy_caches+0x3a/0x46 [ceph]
> SyS_delete_module+0x168/0x240
> ? exit_to_usermode_loop+0x6e/0x93
> entry_SYSCALL_64_fastpath+0x20/0x83
> RIP: 0033:0x7f8650f87c27
> RSP: 002b:00007ffda546ff88 EFLAGS: 00000206
> INFO: Object 0x0000000034be48a6 @offset=0
> kmem_cache_destroy ceph_dentry_info: Slab cache still has objects
> CPU: 0 PID: 27086 Comm: rmmod Tainted: G B 4.15.0-rc8+ #7
> Hardware name: Fedora Project OpenStack Nova, BIOS seabios-1.7.5-11.el7 04/01/2014
> Call Trace:
> dump_stack+0x5c/0x7c
> kmem_cache_destroy+0x203/0x220
> destroy_caches+0x3a/0x46 [ceph]
> SyS_delete_module+0x168/0x240
> ? exit_to_usermode_loop+0x6e/0x93
> entry_SYSCALL_64_fastpath+0x20/0x83
> RIP: 0033:0x7f8650f87c27
>
> Signed-off-by: Chengguang Xu <cgxu519@xxxxxxxxxx>
> ---
> fs/ceph/super.c | 16 +++++-----------
> 1 file changed, 5 insertions(+), 11 deletions(-)
>
> diff --git a/fs/ceph/super.c b/fs/ceph/super.c
> index a62d2a9..26526601 100644
> --- a/fs/ceph/super.c
> +++ b/fs/ceph/super.c
> @@ -836,7 +836,6 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc)
> int err;
> unsigned long started = jiffies; /* note the start time */
> struct dentry *root;
> - int first = 0; /* first vfsmount for this super_block */
>
> dout("mount start %p\n", fsc);
> mutex_lock(&fsc->client->mount_mutex);
> @@ -861,17 +860,17 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc)
> path = fsc->mount_options->server_path + 1;
> dout("mount opening path %s\n", path);
> }
> +
> + err = ceph_fs_debugfs_init(fsc);
> + if (err < 0)
> + goto out;
> +
> root = open_root_dentry(fsc, path, started);
> if (IS_ERR(root)) {
> err = PTR_ERR(root);
> goto out;
> }
> fsc->sb->s_root = dget(root);
> - first = 1;
> -
> - err = ceph_fs_debugfs_init(fsc);
> - if (err < 0)
> - goto fail;
> } else {
> root = dget(fsc->sb->s_root);
> }
> @@ -881,11 +880,6 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc)
> mutex_unlock(&fsc->client->mount_mutex);
> return root;
>
> -fail:
> - if (first) {
> - dput(fsc->sb->s_root);
> - fsc->sb->s_root = NULL;
> - }
> out:
> mutex_unlock(&fsc->client->mount_mutex);
> return ERR_PTR(err);
> --
> 1.8.3.1
>
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