From 740561452df6f151d608d336aaf53bc0c6602e75 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Thu, 9 Oct 2014 15:25:54 -0700 Subject: proc/maps: make vm_is_stack() logic namespace-friendly - Rename vm_is_stack() to task_of_stack() and change it to return "struct task_struct *" rather than the global (and thus wrong in general) pid_t. - Add the new pid_of_stack() helper which calls task_of_stack() and uses the right namespace to report the correct pid_t. Unfortunately we need to define this helper twice, in task_mmu.c and in task_nommu.c. perhaps it makes sense to add fs/proc/util.c and move at least pid_of_stack/task_of_stack there to avoid the code duplication. - Change show_map_vma() and show_numa_map() to use the new helper. Signed-off-by: Oleg Nesterov Cc: Alexander Viro Cc: Cyrill Gorcunov Cc: "Eric W. Biederman" Cc: Greg Ungerer Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: W4TCH0UT Conflicts: fs/proc/task_nommu.c mm/util.c --- fs/proc/task_mmu.c | 25 +++++++++++++++++++++---- fs/proc/task_nommu.c | 21 ++++++++++++++++++++- include/linux/mm.h | 4 ++-- mm/util.c | 27 ++++++++++----------------- 4 files changed, 53 insertions(+), 24 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 91d7958a3..3380c7e63 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -317,13 +317,31 @@ static int do_maps_open(struct inode *inode, struct file *file, sizeof(struct proc_maps_private)); } +static pid_t pid_of_stack(struct proc_maps_private *priv, + struct vm_area_struct *vma, bool is_pid) +{ + struct inode *inode = priv->inode; + struct task_struct *task; + pid_t ret = 0; + + rcu_read_lock(); + task = pid_task(proc_pid(inode), PIDTYPE_PID); + if (task) { + task = task_of_stack(task, vma, is_pid); + if (task) + ret = task_pid_nr_ns(task, inode->i_sb->s_fs_info); + } + rcu_read_unlock(); + + return ret; +} + static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid) { struct mm_struct *mm = vma->vm_mm; struct file *file = vma->vm_file; struct proc_maps_private *priv = m->private; - struct task_struct *task = priv->task; vm_flags_t flags = vma->vm_flags; unsigned long ino = 0; unsigned long long pgoff = 0; @@ -382,8 +400,7 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid) goto done; } - tid = vm_is_stack(task, vma, is_pid); - + tid = pid_of_stack(priv, vma, is_pid); if (tid != 0) { /* * Thread stack in /proc/PID/task/TID/maps or @@ -1411,7 +1428,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid) } else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) { seq_printf(m, " heap"); } else { - pid_t tid = vm_is_stack(task, vma, is_pid); + pid_t tid = pid_of_stack(proc_priv, vma, is_pid); if (tid != 0) { /* * Thread stack in /proc/PID/task/TID/maps or diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c index 9a6f8643c..1f719f621 100644 --- a/fs/proc/task_nommu.c +++ b/fs/proc/task_nommu.c @@ -131,6 +131,25 @@ static void pad_len_spaces(struct seq_file *m, int len) seq_printf(m, "%*c", len, ' '); } +static pid_t pid_of_stack(struct proc_maps_private *priv, + struct vm_area_struct *vma, bool is_pid) +{ + struct inode *inode = priv->inode; + struct task_struct *task; + pid_t ret = 0; + + rcu_read_lock(); + task = pid_task(proc_pid(inode), PIDTYPE_PID); + if (task) { + task = task_of_stack(task, vma, is_pid); + if (task) + ret = task_pid_nr_ns(task, inode->i_sb->s_fs_info); + } + rcu_read_unlock(); + + return ret; +} + /* * display a single VMA to a sequenced file */ @@ -170,7 +189,7 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma, pad_len_spaces(m, len); seq_path(m, &file->f_path, ""); } else if (mm) { - pid_t tid = vm_is_stack(priv->task, vma, is_pid); + pid_t tid = pid_of_stack(priv, vma, is_pid); if (tid != 0) { pad_len_spaces(m, len); diff --git a/include/linux/mm.h b/include/linux/mm.h index 44cbce366..950023cbc 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1137,8 +1137,8 @@ static inline int stack_guard_page_end(struct vm_area_struct *vma, !vma_growsup(vma->vm_next, addr); } -extern pid_t -vm_is_stack(struct task_struct *task, struct vm_area_struct *vma, int in_group); +extern struct task_struct *task_of_stack(struct task_struct *task, + struct vm_area_struct *vma, bool in_group); extern unsigned long move_page_tables(struct vm_area_struct *vma, unsigned long old_addr, struct vm_area_struct *new_vma, diff --git a/mm/util.c b/mm/util.c index a4c6b53d7..dfbda37ae 100644 --- a/mm/util.c +++ b/mm/util.c @@ -260,32 +260,25 @@ static int vm_is_stack_for_task(struct task_struct *t, /* * Check if the vma is being used as a stack. * If is_group is non-zero, check in the entire thread group or else - * just check in the current task. Returns the pid of the task that - * the vma is stack for. + * just check in the current task. Returns the task_struct of the task that + * the vma is stack for. Must be called under rcu_read_lock(). */ -pid_t vm_is_stack(struct task_struct *task, - struct vm_area_struct *vma, int in_group) +struct task_struct *task_of_stack(struct task_struct *task, + struct vm_area_struct *vma, bool in_group) { - pid_t ret = 0; - if (vm_is_stack_for_task(task, vma)) - return task->pid; + return task; if (in_group) { struct task_struct *t; - rcu_read_lock(); - for_each_thread(task, t) { - if (vm_is_stack_for_task(t, vma)) { - ret = t->pid; - goto done; - } - } -done: - rcu_read_unlock(); + for_each_thread(task, t) { + if (vm_is_stack_for_task(t, vma)) + return t; + } } - return ret; + return NULL; } #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) -- cgit v1.2.3