From: Leon Romanovsky <leon@kernel.org>
To: lihongweizz <lihongweizz@inspur.com>
Cc: sagi@grimberg.me, mgurtovoy@nvidia.com, jgg@ziepe.ca,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] IB/iser: Protect tasks cleanup in case iser connection was stopped
Date: Wed, 5 Jul 2023 10:54:03 +0300 [thread overview]
Message-ID: <20230705075403.GI6455@unreal> (raw)
In-Reply-To: <20230704005144.1172-1-lihongweizz@inspur.com>
On Tue, Jul 04, 2023 at 08:51:44AM +0800, lihongweizz wrote:
> From: Rock Li <lihongweizz@inspur.com>
>
> We met a crash issue as below:
> ...
> #7 [ff61b991f6f63d10] page_fault at ffffffffab80111e
> [exception RIP: iscsi_iser_cleanup_task+13]
> RIP: ffffffffc046c04d RSP: ff61b991f6f63dc0 RFLAGS: 00010246
> RAX: 0000000000000000 RBX: ff4bd0aalf7a5610 RCX: ff61b991f6f63dc8
> RDX: ff61b991f6f63d68 RSI: ff61b991f6f63d58 RDI: ff4bd0aalf6cdc00
> RBP: 0000000000000005 R8: 0000000000000073 R9: 0000000000000005
> R10: 0000000000000000 R11: 00000ccde3e0f5c0 R12: ff4bd08c0e0631f8
> R13: ff4bd0a95ffd3c78 R14: ff4bd0a95ffd3c78 R15: ff4bd0aalf6cdc00
> ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
> #8 [ff616991f6f63dc0] __iscsi_put_task at ffffffffc0bd3652 [libiscsi]
> #9 [ff61b991f6f63e00] iscsi_put_task at ffffffffc0bd36e9 [libiscsi]
> ...
>
> After analysing the vmcore, we find that the iser connection was already
> stopped before abort handler running. The iser_conn is already unbindded
> and released. So we add iser connection validation check inside cleanup
> task to fix this corner case.
>
> Signed-off-by: Rock Li <lihongweizz@inspur.com>
> ---
> drivers/infiniband/ulp/iser/iscsi_iser.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
> index bb9aaff92ca3..35dfbf41fc40 100644
> --- a/drivers/infiniband/ulp/iser/iscsi_iser.c
> +++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
> @@ -366,7 +366,12 @@ static void iscsi_iser_cleanup_task(struct iscsi_task *task)
> struct iscsi_iser_task *iser_task = task->dd_data;
> struct iser_tx_desc *tx_desc = &iser_task->desc;
> struct iser_conn *iser_conn = task->conn->dd_data;
> - struct iser_device *device = iser_conn->ib_conn.device;
> + struct iser_device *device;
> +
> + /* stop connection might happens before iser cleanup work */
> + if (!iser_conn)
> + return;
And what prevents from iser_conn being not valid here?
For example, in the flow:
1. Start iscsi_iser_cleanup_task
2. Get valid task->conn->dd_data
3. Pass this if (..) check
4. Context switch and release connection
5. iser_conn now points to released memory.
Thanks
> + device = iser_conn->ib_conn.device;
>
> /* DEVICE_REMOVAL event might have already released the device */
> if (!device)
> --
> 2.27.0
>
next prev parent reply other threads:[~2023-07-05 7:54 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-04 0:51 [PATCH] IB/iser: Protect tasks cleanup in case iser connection was stopped lihongweizz
2023-07-05 7:54 ` Leon Romanovsky [this message]
-- strict thread matches above, loose matches on Subject: below --
2023-07-05 9:22 Rock Li(李宏伟)
2023-07-05 10:36 ` Leon Romanovsky
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