....
That would be the
sysctl_is_seen(PROC_I(dentry->d_inode)->sysctl)
call, and it really looks like 'dentry->d_inode' is NULL:
The whole PROC_I() thing just offsets from the inode:
container_of(inode, struct proc_inode, vfs_inode);
and 'sysctl' is indeed 16 bytes below the vfs inode on x86-64:
struct proc_inode {
...
struct ctl_table_header *sysctl;
struct ctl_table *sysctl_entry;
struct inode vfs_inode;
};
and as far as I can tell, there is nothing to say that a /proc inode
cannot be a negative dentry. Sure, we try to get rid of them, but during a
parallel lookup, we will have added the dentry with a NULL inode in the
other lookup.
So assuming that you have an inode at that point seems to be utter crap.
Now, the whole _function_ is utter crap and should probably be dropped,
but whatever. That's just another sysctl insanity. In the meantime,
something like this does look appropriate, no?
Al, did I miss something?
Linus
---
fs/proc/proc_sysctl.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index f9a8b89..9435fd0 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -386,6 +386,8 @@ static int proc_sys_compare(struct dentry *dir, struct qstr *qstr,
return 1;
if (memcmp(qstr->name, name->name, name->len))
return 1;
+ if (!dentry->d_inode)
+ return 1;
return !sysctl_is_seen(PROC_I(dentry->d_inode)->sysctl);
}
--
