From 61065a30af8df4b8989c2ac7a1f4b4034e4df2d5 Mon Sep 17 00:00:00 2001
From: Glauber Costa <glommer@parallels.com>
Date: Wed, 25 Apr 2012 16:01:48 -0700
Subject: [PATCH] fs/buffer.c: remove BUG() in possible but rare condition
While stressing the kernel with with failing allocations today, I hit the
following chain of events:
alloc_page_buffers():
bh = alloc_buffer_head(GFP_NOFS);
if (!bh)
goto no_grow; <= path taken
grow_dev_page():
bh = alloc_page_buffers(page, size, 0);
if (!bh)
goto failed; <= taken, consequence of the above
and then the failed path BUG()s the kernel.
The failure is inserted a litte bit artificially, but even then, I see no
reason why it should be deemed impossible in a real box.
Even though this is not a condition that we expect to see around every
time, failed allocations are expected to be handled, and BUG() sounds just
too much. As a matter of fact, grow_dev_page() can return NULL just fine
in other circumstances, so I propose we just remove it, then.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/buffer.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index 36d66653b931..351e18ea2e53 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -985,7 +985,6 @@ grow_dev_page(struct block_device *bdev, sector_t block,
return page;
failed:
- BUG();
unlock_page(page);
page_cache_release(page);
return NULL;