Messages in this thread | | | Date | Mon, 7 Aug 2006 15:04:36 -0400 | From | "Dmitry Torokhov" <> | Subject | Re: [patch] Crash on evdev disconnect. |
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On 8/7/06, Zephaniah E. Hull <warp@aehallh.com> wrote: > On Mon, Aug 07, 2006 at 01:35:50PM -0400, Dmitry Torokhov wrote: > > Hi, > > > > On 8/7/06, Zephaniah E. Hull <warp@aehallh.com> wrote: > > > if (evdev->open) { > > > input_close_device(handle); > > > wake_up_interruptible(&evdev->wait); > > >- list_for_each_entry(list, &evdev->list, node) > > >+ list_for_each_entry_safe(list, next, &evdev->list, node) > > > kill_fasync(&list->fasync, SIGIO, POLL_HUP); > > > > NAK. kill_fasync does not affect the list state so using _safe does > > not buy us anything. > > Sorry, but you're wrong. > > Immediately before the kill_fasync call list->node.next is a valid > pointer, immediately afterwords it is 0x100100, which happens to be > list_poison. kill_fasync is triggering a close somehow, evdev_close > deletes that element of the list, which poisons the next value, which > can make us crash and burn. > > I have a 100% reproducible crash case, which is fixed by the change. > > If kill_fasync shouldn't be making it close that's another issue, but at > the moment it is and this is a fairly non-invasive change which fixes > it. >
Unfortunately it does not really fix the problem, it just papers over the issue. The crash will still happen if for some reason evdev_release runs at a bad moment.
> > BTW, dtor_core@ameritech.net address is dead, please use > > dmitry.torokhov@gmail.com or dtor@mail.ru or dtor@isightbb.com. > > Noted, recommend updating the entry in MAINTAINERS. :) >
Already done ;)
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