Commit 5abf186a authored Feb 03, 2017 by Michal Hocko Committed by Linus Torvalds Feb 03, 2017

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/20170201092706.9966-3-mhocko@kernel.org


Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent d1908f52

mm/filemap.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -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,

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