[PATCH v3 0/2] NFS: fix RCU and tracing pointer safety

[Sean Chang <seanwascoding@gmail.com>]

This series addresses two Sparse static analysis warnings in the NFS
client related to RCU safety and pointer attributes.

The first patch resolves a "dereferencing noderef expression" warning 
within the nfs_page_class tracepoint by removing a redundant __private 
attribute that was causing Sparse to complain during trace-buffer 
assignments.

The second patch fixes an RCU-unsafe dereference in nfs_compare_super_address.
It wraps cl_xprt access with rcu_read_lock() and rcu_dereference(). 
Following reviewer feedback, the RCU critical section is kept minimal, 
covering only the transport and network namespace checks.

v3:
  - Patch 2: Removed the redundant XPRT_CONNECTED and pointer existence
    checks as suggested by Benjamin Coddington. Since the comparison is
    performed while holding sb_lock, the transport's existence is guaranteed,
    and its connection state does not affect the server's identity.

v2:
  - Patch 1: Instead of changing the 'req' field type to unsigned long (as in v1),
    simply remove the redundant __private attribute. This resolves the
    Sparse warning while preserving the original pointer type.
  - Patch 2: Reduced RCU read-side critical section scope to cover only
    the necessary transport/net-ns checks, as suggested by reviewers.

Sean Chang (2):
  NFS: remove redundant __private attribute from nfs_page_class
  NFS: Fix RCU dereference of cl_xprt in nfs_compare_super_address

 fs/nfs/nfstrace.h |  2 +-
 fs/nfs/super.c    | 16 +++++++++++++---
 2 files changed, 14 insertions(+), 4 deletions(-)

-- 
2.43.0