On Thu, 16 Oct 2014 16:46:02 -0400 Debabrata Banerjee <dbanerje@xxxxxxxxxx> wrote:
> I don't see why this should print warnings at all instead of properly
> unrolling allocations and returning an appropriate error. It's actually
> leaking resources currently.
I think the warnings are useful - a duplicate name in /proc is a
significant kernel bug and we'll want to know precisely what caused it
and get it fixed up quickly. So let's keep that bit.
> --- a/fs/proc/generic.c
> +++ b/fs/proc/generic.c
> @@ -304,6 +304,7 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
> dp->proc_iops = &proc_file_inode_operations;
> } else {
> WARN_ON(1);
> + proc_free_inum(dp->low_ino);
> return -EINVAL;
> }
>
> @@ -311,9 +312,13 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
>
> for (tmp = dir->subdir; tmp; tmp = tmp->next)
> if (strcmp(tmp->name, dp->name) == 0) {
> - WARN(1, "proc_dir_entry '%s/%s' already registered\n",
> - dir->name, dp->name);
> - break;
> + spin_unlock(&proc_subdir_lock);
> +
> + if (S_ISDIR(dp->mode))
> + dir->nlink--;
> +
> + proc_free_inum(dp->low_ino);
> + return -EEXIST;
> }
Your patch conflicts somewhat with Nicolas's "fs/proc: use a rb tree for
the directory entries". Here's what I ended up with:
From: Debabrata Banerjee <dbanerje@xxxxxxxxxx>
Subject: procfs: fix error handling of proc_register()
proc_register() error paths are leaking inodes and directory refcounts.
Signed-off-by: Debabrata Banerjee <dbanerje@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/generic.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff -puN fs/proc/generic.c~procfs-fix-error-handling-of-proc_register fs/proc/generic.c
--- a/fs/proc/generic.c~procfs-fix-error-handling-of-proc_register
+++ a/fs/proc/generic.c
@@ -369,14 +369,21 @@ static int proc_register(struct proc_dir
dp->proc_iops = &proc_file_inode_operations;
} else {
WARN_ON(1);
+ proc_free_inum(dp->low_ino);
return -EINVAL;
}
spin_lock(&proc_subdir_lock);
dp->parent = dir;
- if (pde_subdir_insert(dir, dp) == false)
+ if (pde_subdir_insert(dir, dp) == false) {
WARN(1, "proc_dir_entry '%s/%s' already registered\n",
dir->name, dp->name);
+ spin_unlock(&proc_subdir_lock);
+ if (S_ISDIR(dp->mode))
+ dir->nlink--;
+ proc_free_inum(dp->low_ino);
+ return -EEXIST;
+ }
spin_unlock(&proc_subdir_lock);
return 0;
_
--
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