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[PATCH 2/3] mm, fs: check for fatal signals in do_generic_file_read

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From: Michal Hocko <mhocko@suse.com>

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.

Cc: stable
Signed-off-by: Michal Hocko <mhocko@suse.com>
---
 mm/filemap.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/mm/filemap.c b/mm/filemap.c
index 14bddd0d7fa4..2ba46f410c7c 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1797,6 +1797,11 @@ 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,
-- 
2.11.0

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Thread

[PATCH 0/3] fix few OOM victim allocation runaways Michal Hocko <mhocko@kernel.org> - 2017-02-01 10:30 +0100
  Re: [PATCH 1/3] fs: break out of iomap_file_buffered_write on         fatal signals Christoph Hellwig <hch@lst.de> - 2017-02-01 10:30 +0100
  [PATCH 3/3] vmalloc: back of when the current is killed Michal Hocko <mhocko@kernel.org> - 2017-02-01 10:30 +0100
  [PATCH 2/3] mm, fs: check for fatal signals in do_generic_file_read Michal Hocko <mhocko@kernel.org> - 2017-02-01 10:30 +0100
  [PATCH 1/3] fs: break out of iomap_file_buffered_write on fatal signals Michal Hocko <mhocko@kernel.org> - 2017-02-01 10:30 +0100
  Re: [PATCH 0/3] fix few OOM victim allocation runaways Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-02-01 13:00 +0100

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