Messages in this thread | | | Date | Mon, 12 Mar 2012 10:22:26 -0400 | From | Vivek Goyal <> | Subject | Re: [PATCH] block: fix ioc leak in put_io_context |
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On Mon, Mar 12, 2012 at 10:59:18AM -0400, Xiaotian Feng wrote: > When put_io_context is called, if ioc->icq_list is empty and refcount > is 1, kernel will not free the ioc. > > This is caught by following kmemleak: > > unreferenced object 0xffff880036349fe0 (size 216): > comm "sh", pid 2137, jiffies 4294931140 (age 290579.412s) > hex dump (first 32 bytes): > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > 01 00 01 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... > backtrace: > [<ffffffff8169f926>] kmemleak_alloc+0x26/0x50 > [<ffffffff81195a9c>] kmem_cache_alloc_node+0x1cc/0x2a0 > [<ffffffff81356b67>] create_io_context_slowpath+0x27/0x130 > [<ffffffff81356d2b>] get_task_io_context+0xbb/0xf0 > [<ffffffff81055f0e>] copy_process+0x188e/0x18b0 > [<ffffffff8105609b>] do_fork+0x11b/0x420 > [<ffffffff810247f8>] sys_clone+0x28/0x30 > [<ffffffff816d3373>] stub_clone+0x13/0x20 > [<ffffffffffffffff>] 0xffffffffffffffff > > ioc->release_work() should be used even if ioc->icq_list is empty. > > Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com> > Cc: Tejun Heo <tj@kernel.org> > Cc: Jens Axboe <axboe@kernel.dk> > --- > block/blk-ioc.c | 3 +-- > 1 files changed, 1 insertions(+), 2 deletions(-) > > diff --git a/block/blk-ioc.c b/block/blk-ioc.c > index 8b782a6..d74a8ce 100644 > --- a/block/blk-ioc.c > +++ b/block/blk-ioc.c > @@ -157,8 +157,7 @@ void put_io_context(struct io_context *ioc) > */ > if (atomic_long_dec_and_test(&ioc->refcount)) { > spin_lock_irqsave(&ioc->lock, flags); > - if (!hlist_empty(&ioc->icq_list)) > - schedule_work(&ioc->release_work); > + schedule_work(&ioc->release_work); > spin_unlock_irqrestore(&ioc->lock, flags);
May be free the ioc right here instead of invoking release_work().
Thanks Vivek
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