On Wed, Apr 23, 2014 at 12:14:52AM -0400, Vince Weaver wrote: > On Tue, 22 Apr 2014, Vince Weaver wrote: > > > This is allowing events to be allocated memory but not being freed somehow > > before returning EINVAL (a memory leak). > > At least it looks like this is happening in the huge traces I have trying > > to track down the perf_fuzzer memory corruption bug. > > I can't find where the memory leak happens, but it looks like this in the > trace: > > [ 3524.626452] perf_fuz-1798 0.... 1271584315us : sys_enter: NR 298 > (698e40, 706, ffffffff, f, 800000000000, 800000000000) > [ 3524.642312] perf_fuz-1798 0.... 1271584324us : kmalloc: > call_site=ffffffff8113a575 ptr=ffff88007d5b0800 bytes_req=1272 > bytes_alloc=2048 gfp_flags=GFP_KERNEL|GFP_ZERO > [ 3524.662598] perf_fuz-1798 0.... 1271584337us : sys_exit: NR 298 = -22 > > The call site for the kmalloc is in perf_event_alloc() > > The memory is eventually freed as: > > [ 3547.895534] <idle>-0 0.Ns. 1271595088us : kfree: > call_site=ffffffff811316aa ptr=ffff88007d5b0800
So perf_event_open() -> err_alloc: -> free_event() -> __free_event() -> call_rcu() -> free_event_rcu() -> kfree(). Would explain that, right? The memory is RCU freed, which means we need to wait a grace period before releasing it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
