From 58cb65487e92b47448d00a711c9f5922137d5678 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Thu, 9 Oct 2014 15:25:54 -0700 Subject: [PATCH] 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 --- fs/proc/task_mmu.c | 25 +++++++++++++++++++++---- fs/proc/task_nommu.c | 21 ++++++++++++++++++++- include/linux/mm.h | 4 ++-- mm/util.c | 23 ++++++++--------------- 4 files changed, 51 insertions(+), 22 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 4793e4a843b0..adddf697c4ea 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -261,13 +261,31 @@ 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; @@ -332,8 +350,7 @@ 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 @@ -1446,7 +1463,7 @@ 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_puts(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 f36e213835cc..599ec2e20104 100644 --- a/fs/proc/task_nommu.c +++ b/fs/proc/task_nommu.c @@ -123,6 +123,25 @@ unsigned long task_statm(struct mm_struct *mm, return size; } +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 */ @@ -163,7 +182,7 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma, seq_pad(m, ' '); 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) { seq_pad(m, ' '); diff --git a/include/linux/mm.h b/include/linux/mm.h index 0f4196a0bc20..28df70774b81 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1247,8 +1247,8 @@ 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 093c973f1697..fec39d4509a9 100644 --- a/mm/util.c +++ b/mm/util.c @@ -170,32 +170,25 @@ 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; - } + if (vm_is_stack_for_task(t, vma)) + return t; } -done: - rcu_read_unlock(); } - return ret; + return NULL; } #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) -- 2.20.1