From 698b8223631472bf982ed570b0812faa61955683 Mon Sep 17 00:00:00 2001 From: Dave Chiluk Date: Tue, 28 May 2013 16:06:08 -0500 Subject: ncpfs: fix rmdir returns Device or resource busy 1d2ef5901483004d74947bbf78d5146c24038fe7 caused a regression in ncpfs such that directories could no longer be removed. This was because ncp_rmdir checked to see if a dentry could be unhashed before allowing it to be removed. Since 1d2ef5901483004d74947bbf78d5146c24038fe7 introduced a change that incremented dentry->d_count causing it to always be greater than 1 unhash would always fail. Thus causing the error path in ncp_rmdir to always be taken. Removing this error path is safe as unhashing is still accomplished by calls to dput from vfs_rmdir. Signed-off-by: Dave Chiluk Signed-off-by: Petr Vandrovec Signed-off-by: Al Viro --- fs/ncpfs/dir.c | 9 --------- 1 file changed, 9 deletions(-) diff --git a/fs/ncpfs/dir.c b/fs/ncpfs/dir.c index 816326093656..6792ce11f2bf 100644 --- a/fs/ncpfs/dir.c +++ b/fs/ncpfs/dir.c @@ -1029,15 +1029,6 @@ static int ncp_rmdir(struct inode *dir, struct dentry *dentry) DPRINTK("ncp_rmdir: removing %s/%s\n", dentry->d_parent->d_name.name, dentry->d_name.name); - /* - * fail with EBUSY if there are still references to this - * directory. - */ - dentry_unhash(dentry); - error = -EBUSY; - if (!d_unhashed(dentry)) - goto out; - len = sizeof(__name); error = ncp_io2vol(server, __name, &len, dentry->d_name.name, dentry->d_name.len, !ncp_preserve_case(dir)); -- cgit v1.2.3 From e7b2c4069252732d52f1de6d1f7c82d99a156659 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 14 Jun 2013 21:09:47 +0200 Subject: fput: task_work_add() can fail if the caller has passed exit_task_work() fput() assumes that it can't be called after exit_task_work() but this is not true, for example free_ipc_ns()->shm_destroy() can do this. In this case fput() silently leaks the file. Change it to fallback to delayed_fput_work if task_work_add() fails. The patch looks complicated but it is not, it changes the code from if (PF_KTHREAD) { schedule_work(...); return; } task_work_add(...) to if (!PF_KTHREAD) { if (!task_work_add(...)) return; /* fallback */ } schedule_work(...); As for shm_destroy() in particular, we could make another fix but I think this change makes sense anyway. There could be another similar user, it is not safe to assume that task_work_add() can't fail. Reported-by: Andrey Vagin Signed-off-by: Oleg Nesterov Signed-off-by: Al Viro --- fs/file_table.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/fs/file_table.c b/fs/file_table.c index cd4d87a82951..485dc0eddd67 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -306,17 +306,18 @@ void fput(struct file *file) { if (atomic_long_dec_and_test(&file->f_count)) { struct task_struct *task = current; + unsigned long flags; + file_sb_list_del(file); - if (unlikely(in_interrupt() || task->flags & PF_KTHREAD)) { - unsigned long flags; - spin_lock_irqsave(&delayed_fput_lock, flags); - list_add(&file->f_u.fu_list, &delayed_fput_list); - schedule_work(&delayed_fput_work); - spin_unlock_irqrestore(&delayed_fput_lock, flags); - return; + if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) { + init_task_work(&file->f_u.fu_rcuhead, ____fput); + if (!task_work_add(task, &file->f_u.fu_rcuhead, true)) + return; } - init_task_work(&file->f_u.fu_rcuhead, ____fput); - task_work_add(task, &file->f_u.fu_rcuhead, true); + spin_lock_irqsave(&delayed_fput_lock, flags); + list_add(&file->f_u.fu_list, &delayed_fput_list); + schedule_work(&delayed_fput_work); + spin_unlock_irqrestore(&delayed_fput_lock, flags); } } -- cgit v1.2.3 From 8aac62706adaaf0fab02c4327761561c8bda9448 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 14 Jun 2013 21:09:49 +0200 Subject: move exit_task_namespaces() outside of exit_notify() exit_notify() does exit_task_namespaces() after forget_original_parent(). This was needed to ensure that ->nsproxy can't be cleared prematurely, an exiting child we are going to reparent can do do_notify_parent() and use the parent's (ours) pid_ns. However, after 32084504 "pidns: use task_active_pid_ns in do_notify_parent" ->nsproxy != NULL is no longer needed, we rely on task_active_pid_ns(). Move exit_task_namespaces() from exit_notify() to do_exit(), after exit_fs() and before exit_task_work(). This solves the problem reported by Andrey, free_ipc_ns()->shm_destroy() does fput() which needs task_work_add(). Note: this particular problem can be fixed if we change fput(), and that change makes sense anyway. But there is another reason to move the callsite. The original reason for exit_task_namespaces() from the middle of exit_notify() was subtle and it has already gone away, now this looks confusing. And this allows us do simplify exit_notify(), we can avoid unlock/lock(tasklist) and we can use ->exit_state instead of PF_EXITING in forget_original_parent(). Reported-by: Andrey Vagin Signed-off-by: Oleg Nesterov Acked-by: "Eric W. Biederman" Acked-by: Andrey Vagin Signed-off-by: Al Viro --- kernel/exit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/exit.c b/kernel/exit.c index af2eb3cbd499..7bb73f9d09db 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -649,7 +649,6 @@ static void exit_notify(struct task_struct *tsk, int group_dead) * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) */ forget_original_parent(tsk); - exit_task_namespaces(tsk); write_lock_irq(&tasklist_lock); if (group_dead) @@ -795,6 +794,7 @@ void do_exit(long code) exit_shm(tsk); exit_files(tsk); exit_fs(tsk); + exit_task_namespaces(tsk); exit_task_work(tsk); check_stack_usage(); exit_thread(); -- cgit v1.2.3 From 05252901199d886a68830befb135d1723730ca86 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 6 Jun 2013 19:33:47 -0400 Subject: use can_lookup() instead of direct checks of ->i_op->lookup a couple of places got missed back when Linus has introduced that one... Signed-off-by: Al Viro --- fs/namei.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 85e40d1c0a8f..9ed9361223c0 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1976,7 +1976,7 @@ static int path_lookupat(int dfd, const char *name, err = complete_walk(nd); if (!err && nd->flags & LOOKUP_DIRECTORY) { - if (!nd->inode->i_op->lookup) { + if (!can_lookup(nd->inode)) { path_put(&nd->path); err = -ENOTDIR; } @@ -2850,7 +2850,7 @@ finish_lookup: if ((open_flag & O_CREAT) && S_ISDIR(nd->inode->i_mode)) goto out; error = -ENOTDIR; - if ((nd->flags & LOOKUP_DIRECTORY) && !nd->inode->i_op->lookup) + if ((nd->flags & LOOKUP_DIRECTORY) && !can_lookup(nd->inode)) goto out; audit_inode(name, nd->path.dentry, 0); finish_open: -- cgit v1.2.3 From dd6c5cd8fedddc9605209098e2fa4e82c7af22aa Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 5 Jun 2013 14:07:08 -0400 Subject: snd_pcm_link(): fix a leak... in case when snd_pcm_stream_linked(substream) is true, we end up leaking group. Signed-off-by: Al Viro --- sound/core/pcm_native.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index ccfa383f1fda..f92818155958 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -1649,6 +1649,7 @@ static int snd_pcm_link(struct snd_pcm_substream *substream, int fd) } if (!snd_pcm_stream_linked(substream)) { substream->group = group; + group = NULL; spin_lock_init(&substream->group->lock); INIT_LIST_HEAD(&substream->group->substreams); list_add_tail(&substream->link_list, &substream->group->substreams); @@ -1663,8 +1664,7 @@ static int snd_pcm_link(struct snd_pcm_substream *substream, int fd) _nolock: snd_card_unref(substream1->pcm->card); fput_light(file, fput_needed); - if (res < 0) - kfree(group); + kfree(group); return res; } -- cgit v1.2.3