From eac3361e3d5dd8067b3258c69615888eb45e9f25 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Mon, 2 Mar 2026 12:55:02 +0900 Subject: [PATCH] ksmbd: fix use-after-free in smb_lazy_parent_lease_break_close() opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is being accessed after rcu_read_unlock() has been called. This creates a race condition where the memory could be freed by a concurrent writer between the unlock and the subsequent pointer dereferences (opinfo->is_lease, etc.), leading to a use-after-free. Fixes: 5fb282ba4fef ("ksmbd: fix possible null-deref in smb_lazy_parent_lease_break_close") Cc: stable@vger.kernel.org Signed-off-by: Namjae Jeon Signed-off-by: Steve French --- fs/smb/server/oplock.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c index 8c9aa17384f3..393a4ae47cc1 100644 --- a/fs/smb/server/oplock.c +++ b/fs/smb/server/oplock.c @@ -1135,10 +1135,12 @@ void smb_lazy_parent_lease_break_close(struct ksmbd_file *fp) rcu_read_lock(); opinfo = rcu_dereference(fp->f_opinfo); - rcu_read_unlock(); - if (!opinfo || !opinfo->is_lease || opinfo->o_lease->version != 2) + if (!opinfo || !opinfo->is_lease || opinfo->o_lease->version != 2) { + rcu_read_unlock(); return; + } + rcu_read_unlock(); p_ci = ksmbd_inode_lookup_lock(fp->filp->f_path.dentry->d_parent); if (!p_ci)