From 0afa5ca82212247456f9de1468b595a111fee633 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 19 Feb 2020 17:17:34 -0600 Subject: [PATCH 1/6] proc: Rename in proc_inode rename sysctl_inodes sibling_inodes I about to need and use the same functionality for pid based inodes and there is no point in adding a second field when this field is already here and serving the same purporse. Just give the field a generic name so it is clear that it is no longer sysctl specific. Also for good measure initialize sibling_inodes when proc_inode is initialized. Signed-off-by: Eric W. Biederman --- fs/proc/inode.c | 1 + fs/proc/internal.h | 2 +- fs/proc/proc_sysctl.c | 8 ++++---- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 6da18316d209..bdae442d5262 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -68,6 +68,7 @@ static struct inode *proc_alloc_inode(struct super_block *sb) ei->pde = NULL; ei->sysctl = NULL; ei->sysctl_entry = NULL; + INIT_HLIST_NODE(&ei->sibling_inodes); ei->ns_ops = NULL; return &ei->vfs_inode; } diff --git a/fs/proc/internal.h b/fs/proc/internal.h index 41587276798e..366cd3aa690b 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -91,7 +91,7 @@ struct proc_inode { struct proc_dir_entry *pde; struct ctl_table_header *sysctl; struct ctl_table *sysctl_entry; - struct hlist_node sysctl_inodes; + struct hlist_node sibling_inodes; const struct proc_ns_operations *ns_ops; struct inode vfs_inode; } __randomize_layout; diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index c75bb4632ed1..42fbb7f3c587 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -279,9 +279,9 @@ static void proc_sys_prune_dcache(struct ctl_table_header *head) node = hlist_first_rcu(&head->inodes); if (!node) break; - ei = hlist_entry(node, struct proc_inode, sysctl_inodes); + ei = hlist_entry(node, struct proc_inode, sibling_inodes); spin_lock(&sysctl_lock); - hlist_del_init_rcu(&ei->sysctl_inodes); + hlist_del_init_rcu(&ei->sibling_inodes); spin_unlock(&sysctl_lock); inode = &ei->vfs_inode; @@ -483,7 +483,7 @@ static struct inode *proc_sys_make_inode(struct super_block *sb, } ei->sysctl = head; ei->sysctl_entry = table; - hlist_add_head_rcu(&ei->sysctl_inodes, &head->inodes); + hlist_add_head_rcu(&ei->sibling_inodes, &head->inodes); head->count++; spin_unlock(&sysctl_lock); @@ -514,7 +514,7 @@ static struct inode *proc_sys_make_inode(struct super_block *sb, void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) { spin_lock(&sysctl_lock); - hlist_del_init_rcu(&PROC_I(inode)->sysctl_inodes); + hlist_del_init_rcu(&PROC_I(inode)->sibling_inodes); if (!--head->count) kfree_rcu(head, rcu); spin_unlock(&sysctl_lock); From 26dbc60f385ff9cff475ea2a3bad02e80fd6fa43 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Thu, 20 Feb 2020 08:34:44 -0600 Subject: [PATCH 2/6] proc: Generalize proc_sys_prune_dcache into proc_prune_siblings_dcache This prepares the way for allowing the pid part of proc to use this dcache pruning code as well. Signed-off-by: Eric W. Biederman --- fs/proc/inode.c | 38 ++++++++++++++++++++++++++++++++++++++ fs/proc/internal.h | 1 + fs/proc/proc_sysctl.c | 35 +---------------------------------- 3 files changed, 40 insertions(+), 34 deletions(-) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index bdae442d5262..74ce4a8d05eb 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -103,6 +103,44 @@ void __init proc_init_kmemcache(void) BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE); } +void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock) +{ + struct inode *inode; + struct proc_inode *ei; + struct hlist_node *node; + struct super_block *sb; + + rcu_read_lock(); + for (;;) { + node = hlist_first_rcu(inodes); + if (!node) + break; + ei = hlist_entry(node, struct proc_inode, sibling_inodes); + spin_lock(lock); + hlist_del_init_rcu(&ei->sibling_inodes); + spin_unlock(lock); + + inode = &ei->vfs_inode; + sb = inode->i_sb; + if (!atomic_inc_not_zero(&sb->s_active)) + continue; + inode = igrab(inode); + rcu_read_unlock(); + if (unlikely(!inode)) { + deactivate_super(sb); + rcu_read_lock(); + continue; + } + + d_prune_aliases(inode); + iput(inode); + deactivate_super(sb); + + rcu_read_lock(); + } + rcu_read_unlock(); +} + static int proc_show_options(struct seq_file *seq, struct dentry *root) { struct super_block *sb = root->d_sb; diff --git a/fs/proc/internal.h b/fs/proc/internal.h index 366cd3aa690b..ba9a991824a5 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -210,6 +210,7 @@ extern const struct inode_operations proc_pid_link_inode_operations; extern const struct super_operations proc_sops; void proc_init_kmemcache(void); +void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock); void set_proc_pid_nlink(void); extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *); extern void proc_entry_rundown(struct proc_dir_entry *); diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 42fbb7f3c587..5da9d7f7ae34 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -269,40 +269,7 @@ static void unuse_table(struct ctl_table_header *p) static void proc_sys_prune_dcache(struct ctl_table_header *head) { - struct inode *inode; - struct proc_inode *ei; - struct hlist_node *node; - struct super_block *sb; - - rcu_read_lock(); - for (;;) { - node = hlist_first_rcu(&head->inodes); - if (!node) - break; - ei = hlist_entry(node, struct proc_inode, sibling_inodes); - spin_lock(&sysctl_lock); - hlist_del_init_rcu(&ei->sibling_inodes); - spin_unlock(&sysctl_lock); - - inode = &ei->vfs_inode; - sb = inode->i_sb; - if (!atomic_inc_not_zero(&sb->s_active)) - continue; - inode = igrab(inode); - rcu_read_unlock(); - if (unlikely(!inode)) { - deactivate_super(sb); - rcu_read_lock(); - continue; - } - - d_prune_aliases(inode); - iput(inode); - deactivate_super(sb); - - rcu_read_lock(); - } - rcu_read_unlock(); + proc_prune_siblings_dcache(&head->inodes, &sysctl_lock); } /* called under sysctl_lock, will reacquire if has to wait */ From 080f6276fccfb3923691e57c1b44a627eabd1a25 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Fri, 21 Feb 2020 08:33:57 -0600 Subject: [PATCH 3/6] proc: In proc_prune_siblings_dcache cache an aquired super block Because there are likely to be several sysctls in a row on the same superblock cache the super_block after the count has been raised and don't deactivate it until we are processing another super_block. Signed-off-by: "Eric W. Biederman" --- fs/proc/inode.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 74ce4a8d05eb..fa2dc732cd77 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -108,10 +108,11 @@ void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock) struct inode *inode; struct proc_inode *ei; struct hlist_node *node; - struct super_block *sb; + struct super_block *old_sb = NULL; rcu_read_lock(); for (;;) { + struct super_block *sb; node = hlist_first_rcu(inodes); if (!node) break; @@ -122,23 +123,28 @@ void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock) inode = &ei->vfs_inode; sb = inode->i_sb; - if (!atomic_inc_not_zero(&sb->s_active)) + if ((sb != old_sb) && !atomic_inc_not_zero(&sb->s_active)) continue; inode = igrab(inode); rcu_read_unlock(); + if (sb != old_sb) { + if (old_sb) + deactivate_super(old_sb); + old_sb = sb; + } if (unlikely(!inode)) { - deactivate_super(sb); rcu_read_lock(); continue; } d_prune_aliases(inode); iput(inode); - deactivate_super(sb); rcu_read_lock(); } rcu_read_unlock(); + if (old_sb) + deactivate_super(old_sb); } static int proc_show_options(struct seq_file *seq, struct dentry *root) From f90f3cafe8d56d593fc509a4185da1d5800efea4 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Fri, 21 Feb 2020 08:43:23 -0600 Subject: [PATCH 4/6] proc: Use d_invalidate in proc_prune_siblings_dcache The function d_prune_aliases has the problem that it will only prune aliases thare are completely unused. It will not remove aliases for the dcache or even think of removing mounts from the dcache. For that behavior d_invalidate is needed. To use d_invalidate replace d_prune_aliases with d_find_alias followed by d_invalidate and dput. For completeness the directory and the non-directory cases are separated because in theory (although not in currently in practice for proc) directories can only ever have a single dentry while non-directories can have hardlinks and thus multiple dentries. As part of this separation use d_find_any_alias for directories to spare d_find_alias the extra work of doing that. Plus the differences between d_find_any_alias and d_find_alias makes it clear why the directory and non-directory code and not share code. To make it clear these routines now invalidate dentries rename proc_prune_siblings_dache to proc_invalidate_siblings_dcache, and rename proc_sys_prune_dcache proc_sys_invalidate_dcache. V2: Split the directory and non-directory cases. To make this code robust to future changes in proc. Signed-off-by: "Eric W. Biederman" --- fs/proc/inode.c | 16 ++++++++++++++-- fs/proc/internal.h | 2 +- fs/proc/proc_sysctl.c | 8 ++++---- 3 files changed, 19 insertions(+), 7 deletions(-) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index fa2dc732cd77..ba6acd300ce1 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -103,7 +103,7 @@ void __init proc_init_kmemcache(void) BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE); } -void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock) +void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock) { struct inode *inode; struct proc_inode *ei; @@ -137,7 +137,19 @@ void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock) continue; } - d_prune_aliases(inode); + if (S_ISDIR(inode->i_mode)) { + struct dentry *dir = d_find_any_alias(inode); + if (dir) { + d_invalidate(dir); + dput(dir); + } + } else { + struct dentry *dentry; + while ((dentry = d_find_alias(inode))) { + d_invalidate(dentry); + dput(dentry); + } + } iput(inode); rcu_read_lock(); diff --git a/fs/proc/internal.h b/fs/proc/internal.h index ba9a991824a5..fd470172675f 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -210,7 +210,7 @@ extern const struct inode_operations proc_pid_link_inode_operations; extern const struct super_operations proc_sops; void proc_init_kmemcache(void); -void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock); +void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock); void set_proc_pid_nlink(void); extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *); extern void proc_entry_rundown(struct proc_dir_entry *); diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 5da9d7f7ae34..b6f5d459b087 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -267,9 +267,9 @@ static void unuse_table(struct ctl_table_header *p) complete(p->unregistering); } -static void proc_sys_prune_dcache(struct ctl_table_header *head) +static void proc_sys_invalidate_dcache(struct ctl_table_header *head) { - proc_prune_siblings_dcache(&head->inodes, &sysctl_lock); + proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock); } /* called under sysctl_lock, will reacquire if has to wait */ @@ -291,10 +291,10 @@ static void start_unregistering(struct ctl_table_header *p) spin_unlock(&sysctl_lock); } /* - * Prune dentries for unregistered sysctls: namespaced sysctls + * Invalidate dentries for unregistered sysctls: namespaced sysctls * can have duplicate names and contaminate dcache very badly. */ - proc_sys_prune_dcache(p); + proc_sys_invalidate_dcache(p); /* * do not remove from the list until nobody holds it; walking the * list in do_sysctl() relies on that. From 71448011ea2a1cd36d8f5cbdab0ed716c454d565 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Thu, 20 Feb 2020 11:17:28 -0600 Subject: [PATCH 5/6] proc: Clear the pieces of proc_inode that proc_evict_inode cares about This just keeps everything tidier, and allows for using flags like SLAB_TYPESAFE_BY_RCU where slabs are not always cleared before reuse. I don't see reuse without reinitializing happening with the proc_inode but I had a false alarm while reworking flushing of proc dentries and indoes when a process dies that caused me to tidy this up. The code is a little easier to follow and reason about this way so I figured the changes might as well be kept. Signed-off-by: "Eric W. Biederman" --- fs/proc/inode.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index ba6acd300ce1..d9243b24554a 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -33,21 +33,27 @@ static void proc_evict_inode(struct inode *inode) { struct proc_dir_entry *de; struct ctl_table_header *head; + struct proc_inode *ei = PROC_I(inode); truncate_inode_pages_final(&inode->i_data); clear_inode(inode); /* Stop tracking associated processes */ - put_pid(PROC_I(inode)->pid); + if (ei->pid) { + put_pid(ei->pid); + ei->pid = NULL; + } /* Let go of any associated proc directory entry */ - de = PDE(inode); - if (de) + de = ei->pde; + if (de) { pde_put(de); + ei->pde = NULL; + } - head = PROC_I(inode)->sysctl; + head = ei->sysctl; if (head) { - RCU_INIT_POINTER(PROC_I(inode)->sysctl, NULL); + RCU_INIT_POINTER(ei->sysctl, NULL); proc_sys_evict_inode(inode, head); } } From 7bc3e6e55acf065500a24621f3b313e7e5998acf Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 19 Feb 2020 18:22:26 -0600 Subject: [PATCH 6/6] proc: Use a list of inodes to flush from proc Rework the flushing of proc to use a list of directory inodes that need to be flushed. The list is kept on struct pid not on struct task_struct, as there is a fixed connection between proc inodes and pids but at least for the case of de_thread the pid of a task_struct changes. This removes the dependency on proc_mnt which allows for different mounts of proc having different mount options even in the same pid namespace and this allows for the removal of proc_mnt which will trivially the first mount of proc to honor it's mount options. This flushing remains an optimization. The functions pid_delete_dentry and pid_revalidate ensure that ordinary dcache management will not attempt to use dentries past the point their respective task has died. When unused the shrinker will eventually be able to remove these dentries. There is a case in de_thread where proc_flush_pid can be called early for a given pid. Which winds up being safe (if suboptimal) as this is just an optiimization. Only pid directories are put on the list as the other per pid files are children of those directories and d_invalidate on the directory will get them as well. So that the pid can be used during flushing it's reference count is taken in release_task and dropped in proc_flush_pid. Further the call of proc_flush_pid is moved after the tasklist_lock is released in release_task so that it is certain that the pid has already been unhashed when flushing it taking place. This removes a small race where a dentry could recreated. As struct pid is supposed to be small and I need a per pid lock I reuse the only lock that currently exists in struct pid the the wait_pidfd.lock. The net result is that this adds all of this functionality with just a little extra list management overhead and a single extra pointer in struct pid. v2: Initialize pid->inodes. I somehow failed to get that initialization into the initial version of the patch. A boot failure was reported by "kernel test robot ", and failure to initialize that pid->inodes matches all of the reported symptoms. Signed-off-by: Eric W. Biederman --- fs/proc/base.c | 111 +++++++++++++--------------------------- fs/proc/inode.c | 2 +- fs/proc/internal.h | 1 + include/linux/pid.h | 1 + include/linux/proc_fs.h | 4 +- kernel/exit.c | 4 +- kernel/pid.c | 1 + 7 files changed, 45 insertions(+), 79 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index c7c64272b0fa..e7efe9d6f3d6 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1834,11 +1834,25 @@ void task_dump_owner(struct task_struct *task, umode_t mode, *rgid = gid; } +void proc_pid_evict_inode(struct proc_inode *ei) +{ + struct pid *pid = ei->pid; + + if (S_ISDIR(ei->vfs_inode.i_mode)) { + spin_lock(&pid->wait_pidfd.lock); + hlist_del_init_rcu(&ei->sibling_inodes); + spin_unlock(&pid->wait_pidfd.lock); + } + + put_pid(pid); +} + struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task, umode_t mode) { struct inode * inode; struct proc_inode *ei; + struct pid *pid; /* We need a new inode */ @@ -1856,10 +1870,18 @@ struct inode *proc_pid_make_inode(struct super_block * sb, /* * grab the reference to task. */ - ei->pid = get_task_pid(task, PIDTYPE_PID); - if (!ei->pid) + pid = get_task_pid(task, PIDTYPE_PID); + if (!pid) goto out_unlock; + /* Let the pid remember us for quick removal */ + ei->pid = pid; + if (S_ISDIR(mode)) { + spin_lock(&pid->wait_pidfd.lock); + hlist_add_head_rcu(&ei->sibling_inodes, &pid->inodes); + spin_unlock(&pid->wait_pidfd.lock); + } + task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid); security_task_to_inode(task, inode); @@ -3230,90 +3252,29 @@ static const struct inode_operations proc_tgid_base_inode_operations = { .permission = proc_pid_permission, }; -static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid) -{ - struct dentry *dentry, *leader, *dir; - char buf[10 + 1]; - struct qstr name; - - name.name = buf; - name.len = snprintf(buf, sizeof(buf), "%u", pid); - /* no ->d_hash() rejects on procfs */ - dentry = d_hash_and_lookup(mnt->mnt_root, &name); - if (dentry) { - d_invalidate(dentry); - dput(dentry); - } - - if (pid == tgid) - return; - - name.name = buf; - name.len = snprintf(buf, sizeof(buf), "%u", tgid); - leader = d_hash_and_lookup(mnt->mnt_root, &name); - if (!leader) - goto out; - - name.name = "task"; - name.len = strlen(name.name); - dir = d_hash_and_lookup(leader, &name); - if (!dir) - goto out_put_leader; - - name.name = buf; - name.len = snprintf(buf, sizeof(buf), "%u", pid); - dentry = d_hash_and_lookup(dir, &name); - if (dentry) { - d_invalidate(dentry); - dput(dentry); - } - - dput(dir); -out_put_leader: - dput(leader); -out: - return; -} - /** - * proc_flush_task - Remove dcache entries for @task from the /proc dcache. - * @task: task that should be flushed. + * proc_flush_pid - Remove dcache entries for @pid from the /proc dcache. + * @pid: pid that should be flushed. * - * When flushing dentries from proc, one needs to flush them from global - * proc (proc_mnt) and from all the namespaces' procs this task was seen - * in. This call is supposed to do all of this job. - * - * Looks in the dcache for - * /proc/@pid - * /proc/@tgid/task/@pid - * if either directory is present flushes it and all of it'ts children - * from the dcache. + * This function walks a list of inodes (that belong to any proc + * filesystem) that are attached to the pid and flushes them from + * the dentry cache. * * It is safe and reasonable to cache /proc entries for a task until * that task exits. After that they just clog up the dcache with * useless entries, possibly causing useful dcache entries to be - * flushed instead. This routine is proved to flush those useless - * dcache entries at process exit time. + * flushed instead. This routine is provided to flush those useless + * dcache entries when a process is reaped. * * NOTE: This routine is just an optimization so it does not guarantee - * that no dcache entries will exist at process exit time it - * just makes it very unlikely that any will persist. + * that no dcache entries will exist after a process is reaped + * it just makes it very unlikely that any will persist. */ -void proc_flush_task(struct task_struct *task) +void proc_flush_pid(struct pid *pid) { - int i; - struct pid *pid, *tgid; - struct upid *upid; - - pid = task_pid(task); - tgid = task_tgid(task); - - for (i = 0; i <= pid->level; i++) { - upid = &pid->numbers[i]; - proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr, - tgid->numbers[i].nr); - } + proc_invalidate_siblings_dcache(&pid->inodes, &pid->wait_pidfd.lock); + put_pid(pid); } static struct dentry *proc_pid_instantiate(struct dentry * dentry, diff --git a/fs/proc/inode.c b/fs/proc/inode.c index d9243b24554a..1e730ea1dcd6 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -40,7 +40,7 @@ static void proc_evict_inode(struct inode *inode) /* Stop tracking associated processes */ if (ei->pid) { - put_pid(ei->pid); + proc_pid_evict_inode(ei); ei->pid = NULL; } diff --git a/fs/proc/internal.h b/fs/proc/internal.h index fd470172675f..9e294f0290e5 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -158,6 +158,7 @@ extern int proc_pid_statm(struct seq_file *, struct pid_namespace *, extern const struct dentry_operations pid_dentry_operations; extern int pid_getattr(const struct path *, struct kstat *, u32, unsigned int); extern int proc_setattr(struct dentry *, struct iattr *); +extern void proc_pid_evict_inode(struct proc_inode *); extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t); extern void pid_update_inode(struct task_struct *, struct inode *); extern int pid_delete_dentry(const struct dentry *); diff --git a/include/linux/pid.h b/include/linux/pid.h index 998ae7d24450..01a0d4e28506 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -62,6 +62,7 @@ struct pid unsigned int level; /* lists of tasks that use this pid */ struct hlist_head tasks[PIDTYPE_MAX]; + struct hlist_head inodes; /* wait queue for pidfd notifications */ wait_queue_head_t wait_pidfd; struct rcu_head rcu; diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 3dfa92633af3..40a7982b7285 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -32,7 +32,7 @@ struct proc_ops { typedef int (*proc_write_t)(struct file *, char *, size_t); extern void proc_root_init(void); -extern void proc_flush_task(struct task_struct *); +extern void proc_flush_pid(struct pid *); extern struct proc_dir_entry *proc_symlink(const char *, struct proc_dir_entry *, const char *); @@ -105,7 +105,7 @@ static inline void proc_root_init(void) { } -static inline void proc_flush_task(struct task_struct *task) +static inline void proc_flush_pid(struct pid *pid) { } diff --git a/kernel/exit.c b/kernel/exit.c index 2833ffb0c211..502b4995b688 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -191,6 +191,7 @@ void put_task_struct_rcu_user(struct task_struct *task) void release_task(struct task_struct *p) { struct task_struct *leader; + struct pid *thread_pid; int zap_leader; repeat: /* don't need to get the RCU readlock here - the process is dead and @@ -199,11 +200,11 @@ repeat: atomic_dec(&__task_cred(p)->user->processes); rcu_read_unlock(); - proc_flush_task(p); cgroup_release(p); write_lock_irq(&tasklist_lock); ptrace_release_task(p); + thread_pid = get_pid(p->thread_pid); __exit_signal(p); /* @@ -226,6 +227,7 @@ repeat: } write_unlock_irq(&tasklist_lock); + proc_flush_pid(thread_pid); release_thread(p); put_task_struct_rcu_user(p); diff --git a/kernel/pid.c b/kernel/pid.c index 0f4ecb57214c..ca08d6a3aa77 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -258,6 +258,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid, INIT_HLIST_HEAD(&pid->tasks[type]); init_waitqueue_head(&pid->wait_pidfd); + INIT_HLIST_HEAD(&pid->inodes); upid = pid->numbers + ns->level; spin_lock_irq(&pidmap_lock);