From ff8c1474cc2f5e11414c71ec4d739c18e6e669c0 Mon Sep 17 00:00:00 2001 From: Xiaotian Feng Date: Wed, 14 Mar 2012 15:34:48 +0100 Subject: [PATCH] block: fix ioc leak in put_io_context 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: [] kmemleak_alloc+0x26/0x50 [] kmem_cache_alloc_node+0x1cc/0x2a0 [] create_io_context_slowpath+0x27/0x130 [] get_task_io_context+0xbb/0xf0 [] copy_process+0x188e/0x18b0 [] do_fork+0x11b/0x420 [] sys_clone+0x28/0x30 [] stub_clone+0x13/0x20 [] 0xffffffffffffffff ioc should be freed if ioc->icq_list is empty. Signed-off-by: Xiaotian Feng Acked-by: Vivek Goyal Acked-by: Tejun Heo Signed-off-by: Jens Axboe --- block/blk-ioc.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/block/blk-ioc.c b/block/blk-ioc.c index 92bf55540d87..fb95dd2f889a 100644 --- a/block/blk-ioc.c +++ b/block/blk-ioc.c @@ -130,6 +130,7 @@ static void ioc_release_fn(struct work_struct *work) void put_io_context(struct io_context *ioc) { unsigned long flags; + bool free_ioc = false; if (ioc == NULL) return; @@ -144,8 +145,13 @@ void put_io_context(struct io_context *ioc) spin_lock_irqsave(&ioc->lock, flags); if (!hlist_empty(&ioc->icq_list)) schedule_work(&ioc->release_work); + else + free_ioc = true; spin_unlock_irqrestore(&ioc->lock, flags); } + + if (free_ioc) + kmem_cache_free(iocontext_cachep, ioc); } EXPORT_SYMBOL(put_io_context); -- 2.20.1