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authorAlexey Dobriyan <adobriyan@gmail.com>2009-03-25 22:48:06 +0300
committerAlexey Dobriyan <adobriyan@gmail.com>2009-03-31 01:14:44 +0400
commit99b76233803beab302123d243eea9e41149804f3 (patch)
tree398178210fe66845ccd6fa4258ba762a87e023ad /arch/x86/kernel/cpu
parent3dec7f59c370c7b58184d63293c3dc984d475840 (diff)
proc 2/2: remove struct proc_dir_entry::owner
Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy as correctly noted at bug #12454. Someone can lookup entry with NULL ->owner, thus not pinning enything, and release it later resulting in module refcount underflow. We can keep ->owner and supply it at registration time like ->proc_fops and ->data. But this leaves ->owner as easy-manipulative field (just one C assignment) and somebody will forget to unpin previous/pin current module when switching ->owner. ->proc_fops is declared as "const" which should give some thoughts. ->read_proc/->write_proc were just fixed to not require ->owner for protection. rmmod'ed directories will be empty and return "." and ".." -- no harm. And directories with tricky enough readdir and lookup shouldn't be modular. We definitely don't want such modular code. Removing ->owner will also make PDE smaller. So, let's nuke it. Kudos to Jeff Layton for reminding about this, let's say, oversight. http://bugzilla.kernel.org/show_bug.cgi?id=12454 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Diffstat (limited to 'arch/x86/kernel/cpu')
-rw-r--r--arch/x86/kernel/cpu/mtrr/if.c10
1 files changed, 1 insertions, 9 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c
index 4c4214690dd..fb73a52913a 100644
--- a/arch/x86/kernel/cpu/mtrr/if.c
+++ b/arch/x86/kernel/cpu/mtrr/if.c
@@ -377,10 +377,6 @@ static const struct file_operations mtrr_fops = {
.release = mtrr_close,
};
-
-static struct proc_dir_entry *proc_root_mtrr;
-
-
static int mtrr_seq_show(struct seq_file *seq, void *offset)
{
char factor;
@@ -423,11 +419,7 @@ static int __init mtrr_if_init(void)
(!cpu_has(c, X86_FEATURE_CENTAUR_MCR)))
return -ENODEV;
- proc_root_mtrr =
- proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops);
-
- if (proc_root_mtrr)
- proc_root_mtrr->owner = THIS_MODULE;
+ proc_create("mtrr", S_IWUSR | S_IRUGO, NULL, &mtrr_fops);
return 0;
}