Le mardi 25 mars 2014 à 19:00 -0500, Alex Elder a écrit :
> On 03/25/2014 06:04 PM, Olivier Bonvalet wrote:
> > Le mardi 25 mars 2014 à 17:46 -0500, Alex Elder a écrit :
> >> On 03/25/2014 05:17 PM, Olivier Bonvalet wrote:
> >>>
> >>> I now have this one very often (here 5 minutes after the host boot) :
> >>
> >> I am fairly sure this indicates a use-after-free scenario,
> >> likely caused by something getting deleted before every
> >> user was done with it.
> >>
> >> I believe Ilya is done for the night; I'm going to spend some
> >> time looking at this to try to determine the cause. If you
> >> are willing I'd love to have you try whatever fix I come up
> >> with. I'd rather find a fix than just collect more information,
> >> but I may need to get more, we'll see.
> >>
> >> Thank you for all your reports, they help a lot.
> >>
> >> -Alex
> >
> > Ok. I can apply some patch to help debug that yes.
> > I will try to reproduce on a different host, without customer data.
> >
> > But I think I will stop here for the night too.
> >
> > Thanks for your time,
> > Olivier
>
> Here's something that will provide a few more pieces of
> information. If you're around and you're able to try it
> out it might confirm something had likely been destroyed.
>
> I'll keep sending stuff as I come up with it (even though
> I realize you may not be around until morning).
>
> -Alex
>
>
> Index: b/drivers/block/rbd.c
> ===================================================================
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -2132,6 +2132,35 @@ static void rbd_img_obj_callback(struct
> spin_lock_irq(&img_request->completion_lock);
> if (which > img_request->next_completion)
> goto out;
> + if (which != img_request->next_completion) {
> + printk("%s: bad image object request information:\n", __func__);
> + printk("obj_request %p\n", obj_request);
> + printk(" ->object_name <%s>\n", obj_request->object_name);
> + printk(" ->offset %llu\n", obj_request->offset);
> + printk(" ->length %llu\n", obj_request->length);
> + printk(" ->type 0x%x\n", (u32)obj_request->type);
> + printk(" ->flags 0x%lx\n", obj_request->flags);
> + printk(" ->img_request %p\n", obj_request->img_request);
> + printk(" ->which %u\n", obj_request->which);
> + printk(" ->xferred %llu\n", obj_request->xferred);
> + printk(" ->result %d\n", obj_request->result);
> + printk(" ->kref %d\n", atomic_read(&obj_request->kref));
> +
> + printk("img_request %p\n", img_request);
> + printk(" ->snap 0x%016llx\n", img_request->snap_id);
> + printk(" ->offset %llu\n", img_request->offset);
> + printk(" ->length %llu\n", img_request->length);
> + printk(" ->flags 0x%lx\n", img_request->flags);
> + printk(" ->obj_request_count %u\n",
> + img_request->obj_request_count);
> + printk(" ->next_completion %u\n",
> + img_request->next_completion);
> + printk(" ->xferred %llu\n", img_request->xferred);
> + printk(" ->result %d\n", img_request->result);
> + printk(" ->obj_requests head %p\n",
> + img_request->obj_requests.next);
> + printk(" ->kref %d\n", atomic_read(&img_request->kref));
> + }
> rbd_assert(which == img_request->next_completion);
>
> for_each_obj_request_from(img_request, obj_request) {
>
>
Thanks for your patch.
This is an output of a crash case :
Mar 26 02:31:18 alg kernel: [ 965.366895] rbd_img_obj_callback: bad image
object request information:
Mar 26 02:31:18 alg kernel: [ 965.366905] obj_request ffff880224bc9528
Mar 26 02:31:18 alg kernel: [ 965.366909] ->object_name <(null)>
Mar 26 02:31:18 alg kernel: [ 965.366913] ->offset 0
Mar 26 02:31:18 alg kernel: [ 965.366917] ->length 4096
Mar 26 02:31:18 alg kernel: [ 965.366921] ->type 0x1
Mar 26 02:31:18 alg kernel: [ 965.366925] ->flags 0x3
Mar 26 02:31:18 alg kernel: [ 965.366929] ->img_request (null)
Mar 26 02:31:18 alg kernel: [ 965.366933] ->which 4294967295
Mar 26 02:31:18 alg kernel: [ 965.366936] ->xferred 4096
Mar 26 02:31:18 alg kernel: [ 965.366940] ->result 0
Mar 26 02:31:18 alg kernel: [ 965.366943] ->kref 0
Mar 26 02:31:18 alg kernel: [ 965.366947] img_request ffff880222f4fb50
Mar 26 02:31:18 alg kernel: [ 965.366950] ->snap 0xfffffffffffffffe
Mar 26 02:31:18 alg kernel: [ 965.366954] ->offset 1417662464
Mar 26 02:31:18 alg kernel: [ 965.366957] ->length 16384
Mar 26 02:31:18 alg kernel: [ 965.366960] ->flags 0x0
Mar 26 02:31:18 alg kernel: [ 965.366963] ->obj_request_count 0
Mar 26 02:31:18 alg kernel: [ 965.366966] ->next_completion 2
Mar 26 02:31:18 alg kernel: [ 965.366969] ->xferred 16384
Mar 26 02:31:18 alg kernel: [ 965.366973] ->result 0
Mar 26 02:31:18 alg kernel: [ 965.366976] ->obj_requests head
ffff880222f4fbb0
Mar 26 02:31:18 alg kernel: [ 965.366980] ->kref 0
Mar 26 02:31:18 alg kernel: [ 965.366985]
Mar 26 02:31:18 alg kernel: [ 965.366985] Assertion failure in
rbd_img_obj_callback() at line 2165:
Mar 26 02:31:18 alg kernel: [ 965.366985]
Mar 26 02:31:18 alg kernel: [ 965.366985] rbd_assert(which ==
img_request->next_completion);
Mar 26 02:31:18 alg kernel: [ 965.366985]
Mar 26 02:31:18 alg kernel: [ 965.367185] ------------[ cut here ]------------
Mar 26 02:31:18 alg kernel: [ 965.367241] kernel BUG at
drivers/block/rbd.c:2165!
I hope it can help.
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