* [PATCH] block: nbd: fix double free
@ 2017-04-28 4:29 Ming Lei
2017-04-28 13:00 ` Josef Bacik
0 siblings, 1 reply; 4+ messages in thread
From: Ming Lei @ 2017-04-28 4:29 UTC (permalink / raw)
To: Jens Axboe, linux-block; +Cc: Christoph Hellwig, Josef Bacik, Ming Lei
Looks it is a typo, just fix it, otherwise the following
warning can be trigerred:
[ming@VM]$sudo rmmod nbd
[sudo] password for ming:
==================================================================
BUG: KASAN: use-after-free in nbd_cleanup+0x115/0x18e [nbd] at addr ffff88024ca539b0
Read of size 8 by task rmmod/2079
Object at ffff88024ca53900, in cache kmalloc-256 size: 256
Allocated:
PID = 1414
Freed:
PID = 2079
Memory state around the buggy address:
ffff88024ca53880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff88024ca53900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88024ca53980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88024ca53a00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
ffff88024ca53a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Fixes: c6a4759ea0c9(nbd: add device refcounting)
Cc: Josef Bacik <jbacik@fb.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
drivers/block/nbd.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 5583dc4ff941..fa44a6fce4cb 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -2110,7 +2110,6 @@ static void __exit nbd_cleanup(void)
if (refcount_read(&nbd->refs) != 2)
printk(KERN_ERR "nbd: possibly leaking a device\n");
nbd_put(nbd);
- nbd_put(nbd);
}
idr_destroy(&nbd_index_idr);
--
2.9.3
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] block: nbd: fix double free
2017-04-28 4:29 [PATCH] block: nbd: fix double free Ming Lei
@ 2017-04-28 13:00 ` Josef Bacik
2017-04-28 15:27 ` Ming Lei
0 siblings, 1 reply; 4+ messages in thread
From: Josef Bacik @ 2017-04-28 13:00 UTC (permalink / raw)
To: Ming Lei, Jens Axboe, linux-block@vger.kernel.org; +Cc: Christoph Hellwig
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] block: nbd: fix double free
2017-04-28 13:00 ` Josef Bacik
@ 2017-04-28 15:27 ` Ming Lei
2017-04-28 15:29 ` Josef Bacik
0 siblings, 1 reply; 4+ messages in thread
From: Ming Lei @ 2017-04-28 15:27 UTC (permalink / raw)
To: Josef Bacik; +Cc: Jens Axboe, linux-block@vger.kernel.org, Christoph Hellwig
On Fri, Apr 28, 2017 at 01:00:30PM +0000, Josef Bacik wrote:
> We should have 2 references on the device at this point, did you see a “nbd: possibly leaking a device” message before the kasan stuff? Thanks,
>
There isn't such message before kasan warning.
Thanks,
Ming
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] block: nbd: fix double free
2017-04-28 15:27 ` Ming Lei
@ 2017-04-28 15:29 ` Josef Bacik
0 siblings, 0 replies; 4+ messages in thread
From: Josef Bacik @ 2017-04-28 15:29 UTC (permalink / raw)
To: Ming Lei; +Cc: Jens Axboe, linux-block@vger.kernel.org, Christoph Hellwig
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-04-28 4:29 [PATCH] block: nbd: fix double free Ming Lei
2017-04-28 13:00 ` Josef Bacik
2017-04-28 15:27 ` Ming Lei
2017-04-28 15:29 ` Josef Bacik
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