From: Shyam Prasad N sprasad@microsoft.com
stable inclusion from stable-v6.6.11 commit 30aae98b75b40e7196ffad18072c42fdb42891ea bugzilla: https://gitee.com/openeuler/kernel/issues/I99TJK
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 09eeb0723f219fbd96d8865bf9b935e03ee2ec22 upstream.
parse_server_interfaces should be in complete charge of maintaining the iface_list linked list. Today, iface entries are removed from the list only when the last refcount is dropped. i.e. in release_iface. However, this can result in undercounting of refcount if the server stops advertising interfaces (which Azure SMB server does).
This change puts parse_server_interfaces in full charge of maintaining the iface_list. So if an empty list is returned by the server, the entries in the list will immediately be removed. This way, a following call to the same function will not find entries in the list.
Fixes: aa45dadd34e4 ("cifs: change iface_list from array to sorted linked list") Cc: stable@vger.kernel.org Signed-off-by: Shyam Prasad N sprasad@microsoft.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: ZhangPeng zhangpeng362@huawei.com --- fs/smb/client/cifsglob.h | 1 - fs/smb/client/smb2ops.c | 27 +++++++++++++++++---------- 2 files changed, 17 insertions(+), 11 deletions(-)
diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h index 4eac7dcb82f9..ec1e5e20a36b 100644 --- a/fs/smb/client/cifsglob.h +++ b/fs/smb/client/cifsglob.h @@ -993,7 +993,6 @@ release_iface(struct kref *ref) struct cifs_server_iface *iface = container_of(ref, struct cifs_server_iface, refcount); - list_del_init(&iface->iface_head); kfree(iface); }
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index 90a881b6c2ee..94e4af4128f1 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -593,16 +593,12 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf, }
/* - * Go through iface_list and do kref_put to remove - * any unused ifaces. ifaces in use will be removed - * when the last user calls a kref_put on it + * Go through iface_list and mark them as inactive */ list_for_each_entry_safe(iface, niface, &ses->iface_list, - iface_head) { + iface_head) iface->is_active = 0; - kref_put(&iface->refcount, release_iface); - ses->iface_count--; - } + spin_unlock(&ses->iface_lock);
/* @@ -676,10 +672,7 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf, iface_head) { ret = iface_cmp(iface, &tmp_iface); if (!ret) { - /* just get a ref so that it doesn't get picked/freed */ iface->is_active = 1; - kref_get(&iface->refcount); - ses->iface_count++; spin_unlock(&ses->iface_lock); goto next_iface; } else if (ret < 0) { @@ -746,6 +739,20 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf, }
out: + /* + * Go through the list again and put the inactive entries + */ + spin_lock(&ses->iface_lock); + list_for_each_entry_safe(iface, niface, &ses->iface_list, + iface_head) { + if (!iface->is_active) { + list_del(&iface->iface_head); + kref_put(&iface->refcount, release_iface); + ses->iface_count--; + } + } + spin_unlock(&ses->iface_lock); + return rc; }