From ebiederm@xmission.com Tue Sep 21 15:26:49 2010 From: Eric W. Biederman To: Greg Kroah-Hartman Cc: Tejun Heo , Hugh Dickins Date: Mon, 20 Sep 2010 00:57:03 -0700 Message-ID: Subject: sysfs: only access bin file vm_ops with the active lock From: Eric W. Biederman 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 Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/bin.c | 42 ++++++++++++++++++++++++++---------------- 1 file changed, 26 insertions(+), 16 deletions(-) --- a/fs/sysfs/bin.c +++ b/fs/sysfs/bin.c @@ -179,13 +179,14 @@ static void bin_vma_open(struct vm_area_ 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_stru 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_ar 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_str 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 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 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_st 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;