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authorMarcelo Tosatti <marcelo@kvack.org>2008-03-13 12:32:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-03-13 13:11:43 -0700
commitfb39380b8d683b55630ba5ba381f4e43e417420e (patch)
tree4fa4386d054b2af1b66651f8cc3d87eeb48ebf73 /fs
parentb500ce8d24d1f14426643da5f6fada28c1f60533 (diff)
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: Marcelo Tosatti <mtosatti@redhat.com> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/task_mmu.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 6dc0334815f..4206454734e 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -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: