Commit fb39380b authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Linus Torvalds

pagemap: proper read error handling

Fix pagemap_read() error handling by releasing acquired resources and checking
for get_user_pages() partial failure.
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Acked-by: default avatarMatt Mackall <mpm@selenic.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b500ce8d
......@@ -640,17 +640,17 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
ret = -EACCES;
if (!ptrace_may_attach(task))
goto out;
goto out_task;
ret = -EINVAL;
/* file position must be aligned */
if (*ppos % PM_ENTRY_BYTES)
goto out;
goto out_task;
ret = 0;
mm = get_task_mm(task);
if (!mm)
goto out;
goto out_task;
ret = -ENOMEM;
uaddr = (unsigned long)buf & PAGE_MASK;
......@@ -658,7 +658,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
pagecount = (PAGE_ALIGN(uend) - uaddr) / PAGE_SIZE;
pages = kmalloc(pagecount * sizeof(struct page *), GFP_KERNEL);
if (!pages)
goto out_task;
goto out_mm;
down_read(&current->mm->mmap_sem);
ret = get_user_pages(current, current->mm, uaddr, pagecount,
......@@ -668,6 +668,12 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
if (ret < 0)
goto out_free;
if (ret != pagecount) {
pagecount = ret;
ret = -EFAULT;
goto out_pages;
}
pm.out = buf;
pm.end = buf + count;
......@@ -699,15 +705,17 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
ret = pm.out - buf;
}
out_pages:
for (; pagecount; pagecount--) {
page = pages[pagecount-1];
if (!PageReserved(page))
SetPageDirty(page);
page_cache_release(page);
}
mmput(mm);
out_free:
kfree(pages);
out_mm:
mmput(mm);
out_task:
put_task_struct(task);
out:
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment