Merge tag 'mm-nonmm-stable-2022-08-06-2' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc updates from Andrew Morton:
 "Updates to various subsystems which I help look after. lib, ocfs2,
  fatfs, autofs, squashfs, procfs, etc. A relatively small amount of
  material this time"

* tag 'mm-nonmm-stable-2022-08-06-2' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits)
  scripts/gdb: ensure the absolute path is generated on initial source
  MAINTAINERS: kunit: add David Gow as a maintainer of KUnit
  mailmap: add linux.dev alias for Brendan Higgins
  mailmap: update Kirill's email
  profile: setup_profiling_timer() is moslty not implemented
  ocfs2: fix a typo in a comment
  ocfs2: use the bitmap API to simplify code
  ocfs2: remove some useless functions
  lib/mpi: fix typo 'the the' in comment
  proc: add some (hopefully) insightful comments
  bdi: remove enum wb_congested_state
  kernel/hung_task: fix address space of proc_dohung_task_timeout_secs
  lib/lzo/lzo1x_compress.c: replace ternary operator with min() and min_t()
  squashfs: support reading fragments in readahead call
  squashfs: implement readahead
  squashfs: always build "file direct" version of page actor
  Revert "squashfs: provide backing_dev_info in order to disable read-ahead"
  fs/ocfs2: Fix spelling typo in comment
  ia64: old_rr4 added under CONFIG_HUGETLB_PAGE
  proc: fix test for "vsyscall=xonly" boot option
  ...

1 files changed, 12 insertions, 7 deletions

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 73aeb4e6d32e..f130499ad843 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -26,8 +26,6 @@
 #include <linux/mount.h>
 #include <linux/bug.h>
 
-#include <linux/uaccess.h>
-
 #include "internal.h"
 
 static void proc_evict_inode(struct inode *inode)
@@ -214,7 +212,15 @@ static void unuse_pde(struct proc_dir_entry *pde)
 		complete(pde->pde_unload_completion);
 }
 
-/* pde is locked on entry, unlocked on exit */
+/*
+ * At most 2 contexts can enter this function: the one doing the last
+ * close on the descriptor and whoever is deleting PDE itself.
+ *
+ * First to enter calls ->proc_release hook and signals its completion
+ * to the second one which waits and then does nothing.
+ *
+ * PDE is locked on entry, unlocked on exit.
+ */
 static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
 	__releases(&pde->pde_unload_lock)
 {
@@ -224,9 +230,6 @@ static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
 	 *
 	 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
 	 * "struct file" needs to be available at the right moment.
-	 *
-	 * Therefore, first process to enter this function does ->release() and
-	 * signals its completion to the other process which does nothing.
 	 */
 	if (pdeo->closing) {
 		/* somebody else is doing that, just wait */
@@ -240,10 +243,12 @@ static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
 
 		pdeo->closing = true;
 		spin_unlock(&pde->pde_unload_lock);
+
 		file = pdeo->file;
 		pde->proc_ops->proc_release(file_inode(file), file);
+
 		spin_lock(&pde->pde_unload_lock);
-		/* After ->release. */
+		/* Strictly after ->proc_release, see above. */
 		list_del(&pdeo->lh);
 		c = pdeo->c;
 		spin_unlock(&pde->pde_unload_lock);