* [PATCH RESEND] nbd: avoid losing pointer to reallocated config->socks in nbd_add_socket
@ 2019-09-20 16:06 Eugene Syromiatnikov
2019-09-22 2:38 ` Xiubo Li
0 siblings, 1 reply; 2+ messages in thread
From: Eugene Syromiatnikov @ 2019-09-20 16:06 UTC (permalink / raw)
To: linux-block, Josef Bacik, nbd; +Cc: linux-kernel, Jens Axboe
In the (very unlikely) case of config->socks reallocation success
and nsock allocation failure config->nsock will not get updated
with the new pointer to socks array. Fix it by updating config->socks
right after reallocation successfulness check.
Fixes: 9561a7ade0c2 ("nbd: add multi-connection support")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Cc: stable@vger.kernel.org # 4.10+
---
drivers/block/nbd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index a8e3815..a04c686 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -987,14 +987,14 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
sockfd_put(sock);
return -ENOMEM;
}
+ config->socks = socks;
+
nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
if (!nsock) {
sockfd_put(sock);
return -ENOMEM;
}
- config->socks = socks;
-
nsock->fallback_index = -1;
nsock->dead = false;
mutex_init(&nsock->tx_lock);
--
2.1.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH RESEND] nbd: avoid losing pointer to reallocated config->socks in nbd_add_socket
2019-09-20 16:06 [PATCH RESEND] nbd: avoid losing pointer to reallocated config->socks in nbd_add_socket Eugene Syromiatnikov
@ 2019-09-22 2:38 ` Xiubo Li
0 siblings, 0 replies; 2+ messages in thread
From: Xiubo Li @ 2019-09-22 2:38 UTC (permalink / raw)
To: Eugene Syromiatnikov, linux-block, Josef Bacik, nbd
Cc: linux-kernel, Jens Axboe
On 2019/9/21 0:06, Eugene Syromiatnikov wrote:
> In the (very unlikely) case of config->socks reallocation success
> and nsock allocation failure config->nsock will not get updated
> with the new pointer to socks array. Fix it by updating config->socks
> right after reallocation successfulness check.
>
> Fixes: 9561a7ade0c2 ("nbd: add multi-connection support")
> Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
> Cc: stable@vger.kernel.org # 4.10+
> ---
> drivers/block/nbd.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index a8e3815..a04c686 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -987,14 +987,14 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
> sockfd_put(sock);
> return -ENOMEM;
> }
> + config->socks = socks;
> +
> nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
> if (!nsock) {
> sockfd_put(sock);
> return -ENOMEM;
> }
>
> - config->socks = socks;
> -
This makes sense.
If the socks allocating successes, then the old config->socks will be
freed by krealloc() and return the new one, but if the nsock allocating
fails, the config->socks will hold the released memory, which may cause
the kernel crash.
Thanks
BRs
> nsock->fallback_index = -1;
> nsock->dead = false;
> mutex_init(&nsock->tx_lock);
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2019-09-22 2:38 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-20 16:06 [PATCH RESEND] nbd: avoid losing pointer to reallocated config->socks in nbd_add_socket Eugene Syromiatnikov
2019-09-22 2:38 ` Xiubo Li
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).