From: ebiederm@xmission.com (Eric W. Biederman)
To: Greg Kroah-Hartman <gregkh@suse.de>
Cc: <linux-kernel@vger.kernel.org>, Tejun Heo <tj@kernel.org>,
Hugh Dickins <hughd@google.com>
Subject: [PATCH 2/2] sysfs: only access bin file vm_ops with the active lock
Date: Mon, 20 Sep 2010 00:57:03 -0700 [thread overview]
Message-ID: <m1vd6026gg.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <m1aanc3l3e.fsf@fess.ebiederm.org> (Eric W. Biederman's message of "Mon, 20 Sep 2010 00:55:33 -0700")
bb->vm_ops is a cached copy of the vm_ops of the underlying
sysfs bin file, which means that after sysfs_bin_remove_file
completes it is only longer valid to deference bb->vm_ops.
So move all of the tests of bb->vm_ops inside of where
we hold the sysfs active lock.
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
---
fs/sysfs/bin.c | 42 ++++++++++++++++++++++++++----------------
1 files changed, 26 insertions(+), 16 deletions(-)
diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c
index d31d7b7..a475983 100644
--- a/fs/sysfs/bin.c
+++ b/fs/sysfs/bin.c
@@ -179,13 +179,14 @@ static void bin_vma_open(struct vm_area_struct *vma)
struct bin_buffer *bb = file->private_data;
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
- if (!bb->vm_ops || !bb->vm_ops->open)
+ if (!bb->vm_ops)
return;
if (!sysfs_get_active(attr_sd))
return;
- bb->vm_ops->open(vma);
+ if (bb->vm_ops->open)
+ bb->vm_ops->open(vma);
sysfs_put_active(attr_sd);
}
@@ -197,13 +198,15 @@ static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
int ret;
- if (!bb->vm_ops || !bb->vm_ops->fault)
+ if (!bb->vm_ops)
return VM_FAULT_SIGBUS;
if (!sysfs_get_active(attr_sd))
return VM_FAULT_SIGBUS;
- ret = bb->vm_ops->fault(vma, vmf);
+ ret = VM_FAULT_SIGBUS;
+ if (bb->vm_ops->fault)
+ ret = bb->vm_ops->fault(vma, vmf);
sysfs_put_active(attr_sd);
return ret;
@@ -219,13 +222,12 @@ static int bin_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
if (!bb->vm_ops)
return VM_FAULT_SIGBUS;
- if (!bb->vm_ops->page_mkwrite)
- return 0;
-
if (!sysfs_get_active(attr_sd))
return VM_FAULT_SIGBUS;
- ret = bb->vm_ops->page_mkwrite(vma, vmf);
+ ret = 0;
+ if (bb->vm_ops->page_mkwrite)
+ ret = bb->vm_ops->page_mkwrite(vma, vmf);
sysfs_put_active(attr_sd);
return ret;
@@ -239,13 +241,15 @@ static int bin_access(struct vm_area_struct *vma, unsigned long addr,
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
int ret;
- if (!bb->vm_ops || !bb->vm_ops->access)
+ if (!bb->vm_ops)
return -EINVAL;
if (!sysfs_get_active(attr_sd))
return -EINVAL;
- ret = bb->vm_ops->access(vma, addr, buf, len, write);
+ ret = -EINVAL;
+ if (bb->vm_ops->access)
+ ret = bb->vm_ops->access(vma, addr, buf, len, write);
sysfs_put_active(attr_sd);
return ret;
@@ -259,13 +263,15 @@ static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
int ret;
- if (!bb->vm_ops || !bb->vm_ops->set_policy)
+ if (!bb->vm_ops)
return 0;
if (!sysfs_get_active(attr_sd))
return -EINVAL;
- ret = bb->vm_ops->set_policy(vma, new);
+ ret = 0;
+ if (bb->vm_ops->set_policy)
+ ret = bb->vm_ops->set_policy(vma, new);
sysfs_put_active(attr_sd);
return ret;
@@ -279,13 +285,15 @@ static struct mempolicy *bin_get_policy(struct vm_area_struct *vma,
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
struct mempolicy *pol;
- if (!bb->vm_ops || !bb->vm_ops->get_policy)
+ if (!bb->vm_ops)
return vma->vm_policy;
if (!sysfs_get_active(attr_sd))
return vma->vm_policy;
- pol = bb->vm_ops->get_policy(vma, addr);
+ pol = vma->vm_policy;
+ if (bb->vm_ops->get_policy)
+ pol = bb->vm_ops->get_policy(vma, addr);
sysfs_put_active(attr_sd);
return pol;
@@ -299,13 +307,15 @@ static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
int ret;
- if (!bb->vm_ops || !bb->vm_ops->migrate)
+ if (!bb->vm_ops)
return 0;
if (!sysfs_get_active(attr_sd))
return 0;
- ret = bb->vm_ops->migrate(vma, from, to, flags);
+ ret = 0;
+ if (bb->vm_ops->migrate)
+ ret = bb->vm_ops->migrate(vma, from, to, flags);
sysfs_put_active(attr_sd);
return ret;
--
1.7.2.2
next prev parent reply other threads:[~2010-09-20 7:57 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-20 7:55 [PATCH 0/2] Fix mmap bugs with sysfs_remove_bin_file Eric W. Biederman
2010-09-20 7:56 ` [PATCH 1/2] sysfs: Fail bin file mmap if vma close is implemented Eric W. Biederman
2010-09-22 19:31 ` Hugh Dickins
2010-09-22 21:01 ` Eric W. Biederman
2010-09-20 7:57 ` Eric W. Biederman [this message]
2010-09-22 19:49 ` [PATCH 2/2] sysfs: only access bin file vm_ops with the active lock Hugh Dickins
2010-09-22 21:59 ` Eric W. Biederman
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