| [PATCH] remove BUG() in possible but rare condition [message #45893] |
Wed, 11 April 2012 18:10  |
Glauber Costa
Messages: 916
Registered: October 2011
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Senior Member |
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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: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
---
fs/buffer.c | 1 -
1 files changed, 0 insertions(+), 1 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index 36d6665..351e18e 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;
--
1.7.7.6
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