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| author | Jens Axboe <jens.axboe@oracle.com> | 2008-05-07 09:17:12 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2008-05-07 09:28:57 +0200 |
| commit | 07416d29bcf608257f1e5280642dcbe0021518a3 (patch) | |
| tree | 6b88b2b043cac10b34234320c68e06848c00127c /block/blk-ioc.c | |
| parent | aa94b5371f6f898558d9fa5690cc6e4bf917a572 (diff) | |
| download | lwn-07416d29bcf608257f1e5280642dcbe0021518a3.tar.gz lwn-07416d29bcf608257f1e5280642dcbe0021518a3.zip | |
cfq-iosched: fix RCU race in the cfq io_context destructor handling
put_io_context() drops the RCU read lock before calling into cfq_dtor(),
however we need to hold off freeing there before grabbing and
dereferencing the first object on the list.
So extend the rcu_read_lock() scope to cover the calling of cfq_dtor(),
and optimize cfq_free_io_context() to use a new variant for
call_for_each_cic() that assumes the RCU read lock is already held.
Hit in the wild by Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-ioc.c')
| -rw-r--r-- | block/blk-ioc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/block/blk-ioc.c b/block/blk-ioc.c index e34df7c9fc36..012f065ac8e2 100644 --- a/block/blk-ioc.c +++ b/block/blk-ioc.c @@ -41,8 +41,8 @@ int put_io_context(struct io_context *ioc) rcu_read_lock(); if (ioc->aic && ioc->aic->dtor) ioc->aic->dtor(ioc->aic); - rcu_read_unlock(); cfq_dtor(ioc); + rcu_read_unlock(); kmem_cache_free(iocontext_cachep, ioc); return 1; |