shmctl: split the work from copyin/copyout
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
parent
5771a8c088
commit
9ba720c186
359
ipc/shm.c
359
ipc/shm.c
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@ -813,23 +813,17 @@ static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
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* NOTE: no locks must be held, the rwsem is taken inside this function.
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*/
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static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
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struct shmid_ds __user *buf, int version)
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struct shmid64_ds *shmid64)
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{
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struct kern_ipc_perm *ipcp;
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struct shmid64_ds shmid64;
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struct shmid_kernel *shp;
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int err;
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if (cmd == IPC_SET) {
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if (copy_shmid_from_user(&shmid64, buf, version))
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return -EFAULT;
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}
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down_write(&shm_ids(ns).rwsem);
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rcu_read_lock();
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ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
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&shmid64.shm_perm, 0);
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&shmid64->shm_perm, 0);
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if (IS_ERR(ipcp)) {
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err = PTR_ERR(ipcp);
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goto out_unlock1;
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@ -849,7 +843,7 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
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goto out_up;
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case IPC_SET:
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ipc_lock_object(&shp->shm_perm);
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err = ipc_update_perm(&shmid64.shm_perm, ipcp);
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err = ipc_update_perm(&shmid64->shm_perm, ipcp);
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if (err)
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goto out_unlock0;
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shp->shm_ctim = get_seconds();
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@ -868,125 +862,175 @@ out_up:
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return err;
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}
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static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
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int cmd, int version, void __user *buf)
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static int shmctl_ipc_info(struct ipc_namespace *ns,
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struct shminfo64 *shminfo)
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{
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int err;
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struct shmid_kernel *shp;
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/* preliminary security checks for *_INFO */
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if (cmd == IPC_INFO || cmd == SHM_INFO) {
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err = security_shm_shmctl(NULL, cmd);
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if (err)
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return err;
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}
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switch (cmd) {
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case IPC_INFO:
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{
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struct shminfo64 shminfo;
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memset(&shminfo, 0, sizeof(shminfo));
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shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
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shminfo.shmmax = ns->shm_ctlmax;
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shminfo.shmall = ns->shm_ctlall;
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shminfo.shmmin = SHMMIN;
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if (copy_shminfo_to_user(buf, &shminfo, version))
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return -EFAULT;
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int err = security_shm_shmctl(NULL, IPC_INFO);
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if (!err) {
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memset(shminfo, 0, sizeof(*shminfo));
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shminfo->shmmni = shminfo->shmseg = ns->shm_ctlmni;
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shminfo->shmmax = ns->shm_ctlmax;
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shminfo->shmall = ns->shm_ctlall;
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shminfo->shmmin = SHMMIN;
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down_read(&shm_ids(ns).rwsem);
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err = ipc_get_maxid(&shm_ids(ns));
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up_read(&shm_ids(ns).rwsem);
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if (err < 0)
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err = 0;
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goto out;
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}
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case SHM_INFO:
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{
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struct shm_info shm_info;
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return err;
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}
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memset(&shm_info, 0, sizeof(shm_info));
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static int shmctl_shm_info(struct ipc_namespace *ns,
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struct shm_info *shm_info)
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{
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int err = security_shm_shmctl(NULL, SHM_INFO);
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if (!err) {
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memset(shm_info, 0, sizeof(*shm_info));
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down_read(&shm_ids(ns).rwsem);
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shm_info.used_ids = shm_ids(ns).in_use;
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shm_get_stat(ns, &shm_info.shm_rss, &shm_info.shm_swp);
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shm_info.shm_tot = ns->shm_tot;
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shm_info.swap_attempts = 0;
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shm_info.swap_successes = 0;
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shm_info->used_ids = shm_ids(ns).in_use;
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shm_get_stat(ns, &shm_info->shm_rss, &shm_info->shm_swp);
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shm_info->shm_tot = ns->shm_tot;
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shm_info->swap_attempts = 0;
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shm_info->swap_successes = 0;
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err = ipc_get_maxid(&shm_ids(ns));
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up_read(&shm_ids(ns).rwsem);
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if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
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err = -EFAULT;
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goto out;
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}
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err = err < 0 ? 0 : err;
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goto out;
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if (err < 0)
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err = 0;
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}
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case SHM_STAT:
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case IPC_STAT:
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{
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struct shmid64_ds tbuf;
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int result;
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return err;
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}
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rcu_read_lock();
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if (cmd == SHM_STAT) {
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shp = shm_obtain_object(ns, shmid);
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if (IS_ERR(shp)) {
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err = PTR_ERR(shp);
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goto out_unlock;
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}
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result = shp->shm_perm.id;
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} else {
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shp = shm_obtain_object_check(ns, shmid);
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if (IS_ERR(shp)) {
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err = PTR_ERR(shp);
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goto out_unlock;
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}
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result = 0;
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}
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static int shmctl_stat(struct ipc_namespace *ns, int shmid,
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int cmd, struct shmid64_ds *tbuf)
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{
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struct shmid_kernel *shp;
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int result;
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int err;
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err = -EACCES;
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if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
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rcu_read_lock();
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if (cmd == SHM_STAT) {
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shp = shm_obtain_object(ns, shmid);
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if (IS_ERR(shp)) {
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err = PTR_ERR(shp);
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goto out_unlock;
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err = security_shm_shmctl(shp, cmd);
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if (err)
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}
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result = shp->shm_perm.id;
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} else {
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shp = shm_obtain_object_check(ns, shmid);
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if (IS_ERR(shp)) {
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err = PTR_ERR(shp);
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goto out_unlock;
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memset(&tbuf, 0, sizeof(tbuf));
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kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
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tbuf.shm_segsz = shp->shm_segsz;
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tbuf.shm_atime = shp->shm_atim;
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tbuf.shm_dtime = shp->shm_dtim;
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tbuf.shm_ctime = shp->shm_ctim;
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tbuf.shm_cpid = shp->shm_cprid;
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tbuf.shm_lpid = shp->shm_lprid;
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tbuf.shm_nattch = shp->shm_nattch;
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rcu_read_unlock();
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if (copy_shmid_to_user(buf, &tbuf, version))
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err = -EFAULT;
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else
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err = result;
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goto out;
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}
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default:
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return -EINVAL;
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}
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result = 0;
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}
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err = -EACCES;
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if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
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goto out_unlock;
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err = security_shm_shmctl(shp, cmd);
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if (err)
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goto out_unlock;
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memset(tbuf, 0, sizeof(*tbuf));
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kernel_to_ipc64_perm(&shp->shm_perm, &tbuf->shm_perm);
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tbuf->shm_segsz = shp->shm_segsz;
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tbuf->shm_atime = shp->shm_atim;
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tbuf->shm_dtime = shp->shm_dtim;
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tbuf->shm_ctime = shp->shm_ctim;
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tbuf->shm_cpid = shp->shm_cprid;
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tbuf->shm_lpid = shp->shm_lprid;
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tbuf->shm_nattch = shp->shm_nattch;
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rcu_read_unlock();
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return result;
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out_unlock:
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rcu_read_unlock();
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out:
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return err;
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}
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static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
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{
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struct shmid_kernel *shp;
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struct file *shm_file;
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int err;
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rcu_read_lock();
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shp = shm_obtain_object_check(ns, shmid);
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if (IS_ERR(shp)) {
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err = PTR_ERR(shp);
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goto out_unlock1;
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}
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audit_ipc_obj(&(shp->shm_perm));
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err = security_shm_shmctl(shp, cmd);
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if (err)
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goto out_unlock1;
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ipc_lock_object(&shp->shm_perm);
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/* check if shm_destroy() is tearing down shp */
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if (!ipc_valid_object(&shp->shm_perm)) {
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err = -EIDRM;
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goto out_unlock0;
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}
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if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
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kuid_t euid = current_euid();
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if (!uid_eq(euid, shp->shm_perm.uid) &&
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!uid_eq(euid, shp->shm_perm.cuid)) {
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err = -EPERM;
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goto out_unlock0;
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}
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if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
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err = -EPERM;
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goto out_unlock0;
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}
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}
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shm_file = shp->shm_file;
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if (is_file_hugepages(shm_file))
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goto out_unlock0;
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if (cmd == SHM_LOCK) {
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struct user_struct *user = current_user();
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err = shmem_lock(shm_file, 1, user);
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if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
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shp->shm_perm.mode |= SHM_LOCKED;
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shp->mlock_user = user;
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}
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goto out_unlock0;
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}
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/* SHM_UNLOCK */
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if (!(shp->shm_perm.mode & SHM_LOCKED))
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goto out_unlock0;
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shmem_lock(shm_file, 0, shp->mlock_user);
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shp->shm_perm.mode &= ~SHM_LOCKED;
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shp->mlock_user = NULL;
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get_file(shm_file);
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ipc_unlock_object(&shp->shm_perm);
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rcu_read_unlock();
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shmem_unlock_mapping(shm_file->f_mapping);
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fput(shm_file);
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return err;
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out_unlock0:
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ipc_unlock_object(&shp->shm_perm);
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out_unlock1:
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rcu_read_unlock();
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return err;
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}
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SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
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{
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struct shmid_kernel *shp;
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int err, version;
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struct ipc_namespace *ns;
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struct shmid64_ds tbuf;
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if (cmd < 0 || shmid < 0)
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return -EINVAL;
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@ -995,91 +1039,44 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
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ns = current->nsproxy->ipc_ns;
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switch (cmd) {
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case IPC_INFO:
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case SHM_INFO:
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case SHM_STAT:
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case IPC_STAT:
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return shmctl_nolock(ns, shmid, cmd, version, buf);
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case IPC_RMID:
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case IPC_SET:
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return shmctl_down(ns, shmid, cmd, buf, version);
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case SHM_LOCK:
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case SHM_UNLOCK:
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{
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struct file *shm_file;
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rcu_read_lock();
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shp = shm_obtain_object_check(ns, shmid);
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if (IS_ERR(shp)) {
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err = PTR_ERR(shp);
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goto out_unlock1;
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}
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audit_ipc_obj(&(shp->shm_perm));
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err = security_shm_shmctl(shp, cmd);
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if (err)
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goto out_unlock1;
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ipc_lock_object(&shp->shm_perm);
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/* check if shm_destroy() is tearing down shp */
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if (!ipc_valid_object(&shp->shm_perm)) {
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err = -EIDRM;
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goto out_unlock0;
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}
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if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
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kuid_t euid = current_euid();
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if (!uid_eq(euid, shp->shm_perm.uid) &&
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!uid_eq(euid, shp->shm_perm.cuid)) {
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err = -EPERM;
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goto out_unlock0;
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}
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if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
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err = -EPERM;
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goto out_unlock0;
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}
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}
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shm_file = shp->shm_file;
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if (is_file_hugepages(shm_file))
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goto out_unlock0;
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if (cmd == SHM_LOCK) {
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struct user_struct *user = current_user();
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err = shmem_lock(shm_file, 1, user);
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if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
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shp->shm_perm.mode |= SHM_LOCKED;
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shp->mlock_user = user;
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}
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goto out_unlock0;
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}
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/* SHM_UNLOCK */
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if (!(shp->shm_perm.mode & SHM_LOCKED))
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goto out_unlock0;
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shmem_lock(shm_file, 0, shp->mlock_user);
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shp->shm_perm.mode &= ~SHM_LOCKED;
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shp->mlock_user = NULL;
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get_file(shm_file);
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ipc_unlock_object(&shp->shm_perm);
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rcu_read_unlock();
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shmem_unlock_mapping(shm_file->f_mapping);
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fput(shm_file);
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case IPC_INFO: {
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struct shminfo64 shminfo;
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err = shmctl_ipc_info(ns, &shminfo);
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if (err < 0)
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return err;
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if (copy_shminfo_to_user(buf, &shminfo, version))
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err = -EFAULT;
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return err;
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}
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case SHM_INFO: {
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struct shm_info shm_info;
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err = shmctl_shm_info(ns, &shm_info);
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if (err < 0)
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return err;
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if (copy_to_user(buf, &shm_info, sizeof(shm_info)))
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err = -EFAULT;
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return err;
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}
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case SHM_STAT:
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case IPC_STAT: {
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err = shmctl_stat(ns, shmid, cmd, &tbuf);
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if (err < 0)
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return err;
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if (copy_shmid_to_user(buf, &tbuf, version))
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err = -EFAULT;
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return err;
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}
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case IPC_SET:
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if (copy_shmid_from_user(&tbuf, buf, version))
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return -EFAULT;
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case IPC_RMID:
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return shmctl_down(ns, shmid, cmd, &tbuf);
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case SHM_LOCK:
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case SHM_UNLOCK:
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return shmctl_do_lock(ns, shmid, cmd);
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default:
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return -EINVAL;
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}
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out_unlock0:
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ipc_unlock_object(&shp->shm_perm);
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out_unlock1:
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rcu_read_unlock();
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return err;
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}
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/*
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