Merge tag 'vfs-7.3-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:

 - netfs:

     - Fix an uninitialized return value in netfs_unbuffered_write()
       when preparing the first subrequest fails

     - For partial unbuffered/DIO writes return the amount transferred
       rather than an error

     - Update i_size with the amount actually written when a partial
       transfer ends in an error

     - Fix a subrequest reference leak when the io_iter ends up empty

     - Handle netfs_alloc_subrequest() failure during unbuffered writes

     - Load all readahead folios into the rolling buffer upfront and
       drop the readahead references once the first subrequest is
       dispatched

     - Mark folios for copy-to-cache while issuing subrequests

     - Fix read progress reporting

 - afs:

     - Add the missing kunmap in the error path of afs_dir_search_bucket()

     - Fix a double kunmap in afs_edit_dir_remove()

     - Don't free an existing server's endpoint state when cleaning up a
       candidate server in afs_lookup_server()

     - Unbind peers removed from a server's address list

 - ufs:

     - Load the cylinder group metadata before creating the root dentry

     - Validate the cylinder group index and rotor positions before
       caching them

     - Treat an unreadable directory block as not empty

 - exec:

     - Close the close-on-exec files before taking exec_update_lock

       Closing a file can block on the filesystem, so a hung filesystem
       blocked everything that takes exec_update_lock and a FUSE server
       inspecting the calling process could deadlock

     - Drop the bprm loader before closing bprm->file in free_bprm()

 - exit: Hold a reference to thread_pid across proc_flush_pid()

 - reboot: Fix a use-after-free on cad_pid

 - nsfs: Keep the namespace tree fields out of the rcu_head used by
   kfree_rcu()

 - nstree: Check listing permission before taking a namespace
   reference in listns()

 - super: Return 0 when a nested thaw drops its hold while other
   freezers remain

 - ext4: Don't set I_METADATA_WRITEBACK during fastcommit replay

 - adfs: Free s_fs_info in ->kill_sb()

 - autofs: Free the inode info allocated in autofs_fill_super() when
   the root inode allocation fails

 - ovl: Return EINVAL instead of EIO on a user namespace mismatch now
   that it's a plain refusal and not an internal error

 - cachefiles: Don't cast the variable-length coherency data to a
   __be64 in the coherency tracepoint

* tag 'vfs-7.3-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (28 commits)
  nstree: check listing permission before taking a namespace reference
  exec: do_close_on_exec() before taking exec_update_lock
  exit: hold a reference to thread_pid across proc_flush_pid
  fs: autofs: fix memory leak in autofs_fill_super()
  exec: Drop bprm loader before closing bprm->file
  afs: Clear stale peer app data after address list changes
  afs: Fix incorrect free in candidate cleanup in afs_lookup_server()
  afs: Fix double-unmap of directory block
  afs: Fix missing kunmap in afs_dir_search_bucket()
  ovl: return EINVAL instead of EIO in case of mismatched user_ns
  reboot: fix cad_pid use-after-free race
  cachefiles: Fix potential UAF/KASAN warning
  netfs: Fix read progress reporting
  netfs: Mark folios with COPY_TO_CACHE whilst issuing subreqs
  netfs: Fix readahead synchronisation issues by loading all folios upfront
  netfs: break unbuffered write when netfs_alloc_subrequest() fails
  netfs: Fix subreq ref leak
  netfs: Fix i_size update for partial transfer
  netfs: Fix error vs transferred passed to ->ki_complete()
  netfs: Fix unbuffered/DIO write partial transfer error return
  ...

1 files changed, 6 insertions, 3 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 97686af89501..4e028f157597 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -261,8 +261,11 @@ repeat:
 	pidfs_exit(p);
 	cgroup_task_release(p);
 
-	/* Retrieve @thread_pid before __unhash_process() may set it to NULL. */
-	thread_pid = task_pid(p);
+	/*
+	 * Pin @thread_pid before __unhash_process() clears it. The last
+	 * PIDTYPE detach can otherwise free it before proc_flush_pid().
+	 */
+	thread_pid = get_pid(task_pid(p));
 
 	write_lock_irq(&tasklist_lock);
 	ptrace_release_task(p);
@@ -291,8 +294,8 @@ repeat:
 	}
 
 	write_unlock_irq(&tasklist_lock);
-	/* @thread_pid can't go away until free_pids() below */
 	proc_flush_pid(thread_pid);
+	put_pid(thread_pid);
 	exit_cred_namespaces(p);
 	add_device_randomness(&p->se.sum_exec_runtime,
 			      sizeof(p->se.sum_exec_runtime));