mm, fs: check for fatal signals in do_generic_file_read()

do_generic_file_read() can be told to perform a large request from userspace. If the system is under OOM and the reading task is the OOM victim then it has an access to memory reserves and finishing the full request can lead to the full memory depletion which is dangerous. Make sure we rather go with a short read and allow the killed task to terminate. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Michal Hocko <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Cc: Tetsuo Handa <[email protected]> Cc: Al Viro <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
zhenyw · Feb 3, 2017 · 5abf186 · 5abf186
1 parent d1908f5
commit 5abf186
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/mm/filemap.c b/mm/filemap.c
@@ -1791,6 +1791,11 @@ static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos,
 
 		cond_resched();
 find_page:
+		if (fatal_signal_pending(current)) {
+			error = -EINTR;
+			goto out;
+		}
+
 		page = find_get_page(mapping, index);
 		if (!page) {
 			page_cache_sync_readahead(mapping,