提交 6ecdcbcd 编写于 作者: K Konstantin Khlebnikov 提交者: Greg Kroah-Hartman

proc: use down_read_killable mmap_sem for /proc/pid/map_files

[ Upstream commit cd9e2bb8271c971d9f37c722be2616c7f8ba0664 ]

Do not remain stuck forever if something goes wrong.  Using a killable
lock permits cleanup of stuck tasks and simplifies investigation.

It seems ->d_revalidate() could return any error (except ECHILD) to abort
validation and pass error as result of lookup sequence.

[akpm@linux-foundation.org: fix proc_map_files_lookup() return value, per Andrei]
Link: http://lkml.kernel.org/r/156007493995.3335.9595044802115356911.stgit@buzzSigned-off-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: NRoman Gushchin <guro@fb.com>
Reviewed-by: NCyrill Gorcunov <gorcunov@gmail.com>
Reviewed-by: NKirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
上级 3d617da8
......@@ -1960,9 +1960,12 @@ static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
goto out;
if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
down_read(&mm->mmap_sem);
exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
up_read(&mm->mmap_sem);
status = down_read_killable(&mm->mmap_sem);
if (!status) {
exact_vma_exists = !!find_exact_vma(mm, vm_start,
vm_end);
up_read(&mm->mmap_sem);
}
}
mmput(mm);
......@@ -2008,8 +2011,11 @@ static int map_files_get_link(struct dentry *dentry, struct path *path)
if (rc)
goto out_mmput;
rc = down_read_killable(&mm->mmap_sem);
if (rc)
goto out_mmput;
rc = -ENOENT;
down_read(&mm->mmap_sem);
vma = find_exact_vma(mm, vm_start, vm_end);
if (vma && vma->vm_file) {
*path = vma->vm_file->f_path;
......@@ -2105,7 +2111,11 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
if (!mm)
goto out_put_task;
down_read(&mm->mmap_sem);
result = ERR_PTR(-EINTR);
if (down_read_killable(&mm->mmap_sem))
goto out_put_mm;
result = ERR_PTR(-ENOENT);
vma = find_exact_vma(mm, vm_start, vm_end);
if (!vma)
goto out_no_vma;
......@@ -2116,6 +2126,7 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
out_no_vma:
up_read(&mm->mmap_sem);
out_put_mm:
mmput(mm);
out_put_task:
put_task_struct(task);
......@@ -2157,7 +2168,12 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
mm = get_task_mm(task);
if (!mm)
goto out_put_task;
down_read(&mm->mmap_sem);
ret = down_read_killable(&mm->mmap_sem);
if (ret) {
mmput(mm);
goto out_put_task;
}
nr_files = 0;
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册