The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Possible dependencies:

51884d153f7e ("ceph: avoid putting the realm twice when decoding snaps fails") 2e586641c950 ("ceph: do not update snapshot context when there is no new snapshot")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 51884d153f7ec85e18d607b2467820a90e0f4359 Mon Sep 17 00:00:00 2001 From: Xiubo Li xiubli@redhat.com Date: Wed, 9 Nov 2022 11:00:39 +0800 Subject: [PATCH] ceph: avoid putting the realm twice when decoding snaps fails

When decoding the snaps fails it maybe leaving the 'first_realm' and 'realm' pointing to the same snaprealm memory. And then it'll put it twice and could cause random use-after-free, BUG_ON, etc issues.

Cc: stable@vger.kernel.org Link: https://tracker.ceph.com/issues/57686 Signed-off-by: Xiubo Li xiubli@redhat.com Reviewed-by: Ilya Dryomov idryomov@gmail.com Signed-off-by: Ilya Dryomov idryomov@gmail.com

diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index 864cdaa0d2bd..e4151852184e 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -763,7 +763,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, struct ceph_mds_snap_realm *ri; /* encoded */ __le64 *snaps; /* encoded */ __le64 *prior_parent_snaps; /* encoded */ - struct ceph_snap_realm *realm = NULL; + struct ceph_snap_realm *realm; struct ceph_snap_realm *first_realm = NULL; struct ceph_snap_realm *realm_to_rebuild = NULL; int rebuild_snapcs; @@ -774,6 +774,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc,

dout("%s deletion=%d\n", __func__, deletion); more: + realm = NULL; rebuild_snapcs = 0; ceph_decode_need(&p, e, sizeof(*ri), bad); ri = p;