Messages in this thread | | | Subject | Re: mm_alloc()'ed structure leak | From | Peter Zijlstra <> | Date | Mon, 09 Feb 2009 16:12:43 +0100 |
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On Mon, 2009-02-09 at 14:44 +0000, Catalin Marinas wrote: > On Mon, 2009-02-09 at 12:18 +0000, Catalin Marinas wrote: > > Basically bash forks and executes a command like "host kernel.org" which > > finishes normally but the corresponding mm_struct isn't freed (I get > > this consistently every time I run the above command): > > > > unreferenced object 0xcfed4070 (size 368): > > comm "bash", pid 1674, jiffies 421592 > > backtrace: > > [<c0082bd4>] kmemleak_alloc+0x140/0x2b0 > > [<c007ff2c>] kmem_cache_alloc+0xd0/0x100 > > [<c0036980>] mm_alloc+0x14/0x44 > > [<c008a99c>] bprm_mm_init+0xc/0x13c > > [<c008ab70>] do_execve+0xa4/0x218 > > [<c002718c>] sys_execve+0x34/0x54 > > [<c0023e80>] ret_fast_syscall+0x0/0x28 > > Dumping the object in question: > > mm_struct.mm_users = 0 > mm_struct.mm_count = 1 > > It looks like the mm_count didn't get to 0 hence no structure freeing > via mmdrop(). > > The leak disappears if I revert commit 38d47c1b7075 - "futex: rely on > get_user_pages() for shared futexes". Peter, any idea?
Looks like the futex key references go wrong somewhere, I'll go look at it.
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