kernfs: protect lazy kernfs_iattrs allocation with mutex

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commit 4afddd60a7 upstream.

kernfs_iattrs is allocated lazily when operations which require it
take place; unfortunately, the lazy allocation and returning weren't
properly synchronized and when there are multiple concurrent
operations, it might end up returning kernfs_iattrs which hasn't
finished initialization yet or different copies to different callers.

Fix it by synchronizing with a mutex.  This can be smarter with memory
barriers but let's go there if it actually turns out to be necessary.

Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/g/533ABA32.9080602@oracle.com
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Tejun Heo 2014-04-02 16:40:52 -04:00 • committed by Greg Kroah-Hartman

parent 52d6c48c9d

commit 29b311867d

1 changed files with 10 additions and 4 deletions

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fs/kernfs/inode.c

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