Re: [PATCH v2] sparse: fix incorrect fmode_t casts

From: Christoph Hellwig
Date: Wed May 18 2022 - 09:22:57 EST


The fanotify and open.c changes looks fine, but should be split
into one each with a proper subject and description.

For procfs something simpler like the patch below might be a better
option:

diff --git a/fs/proc/base.c b/fs/proc/base.c
index c1031843cc6aa..c07c6b51f0cb9 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2237,13 +2237,13 @@ static struct dentry *
proc_map_files_instantiate(struct dentry *dentry,
struct task_struct *task, const void *ptr)
{
- fmode_t mode = (fmode_t)(unsigned long)ptr;
+ const fmode_t *mode = ptr;
struct proc_inode *ei;
struct inode *inode;

inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK |
- ((mode & FMODE_READ ) ? S_IRUSR : 0) |
- ((mode & FMODE_WRITE) ? S_IWUSR : 0));
+ ((*mode & FMODE_READ ) ? S_IRUSR : 0) |
+ ((*mode & FMODE_WRITE) ? S_IWUSR : 0));
if (!inode)
return ERR_PTR(-ENOENT);

@@ -2294,7 +2294,7 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,

if (vma->vm_file)
result = proc_map_files_instantiate(dentry, task,
- (void *)(unsigned long)vma->vm_file->f_mode);
+ &vma->vm_file->f_mode);

out_no_vma:
mmap_read_unlock(mm);
@@ -2391,7 +2391,7 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
buf, len,
proc_map_files_instantiate,
task,
- (void *)(unsigned long)p->mode))
+ &p->mode))
break;
ctx->pos++;
}