On Fri, 2022-03-04 at 16:14 +0000, Luís Henriques wrote:
> After calling ceph_mdsc_put_request() on dfi->last_readdir, this field
> should be set to NULL, otherwise we may end-up freeing it twince and get
> the following splat:
>
> refcount_t: underflow; use-after-free.
> WARNING: CPU: 0 PID: 229 at lib/refcount.c:28 refcount_warn_saturate+0xa6/0xf0
> ...
> Call Trace:
> <TASK>
> ceph_readdir+0xd35/0x1460 [ceph]
> ? _raw_spin_unlock+0x12/0x30
> ? preempt_count_add+0x73/0xa0
> ? _raw_spin_unlock+0x12/0x30
> ? __mark_inode_dirty+0x27c/0x3a0
> iterate_dir+0x7d/0x190
> __x64_sys_getdents64+0x80/0x120
> ? compat_fillonedir+0x160/0x160
> do_syscall_64+0x43/0x90
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Signed-off-by: Luís Henriques <lhenriques@xxxxxxx>
> ---
> fs/ceph/dir.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> index 0bcb677d2199..934402f5e9e6 100644
> --- a/fs/ceph/dir.c
> +++ b/fs/ceph/dir.c
> @@ -555,6 +555,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
> le32_to_cpu(rde->inode.in->mode) >> 12)) {
> dout("filldir stopping us...\n");
> ceph_mdsc_put_request(dfi->last_readdir);
> + dfi->last_readdir = NULL;
> err = 0;
> goto out;
> }
I think Xiubo fixed this in the testing branch late yesterday. It should
no longer be needed.
Thanks,
--
Jeff Layton <jlayton@xxxxxxxxxx>
