Messages in this thread | | | Date | Tue, 30 Aug 2022 16:29:21 +0300 | Subject | Re: [PATCH] nvmet-tcp: Fix NULL pointer dereference during release | From | Sagi Grimberg <> |
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On 8/30/22 11:36, zhenwei pi wrote: > nvmet-tcp frees CMD buffers in nvmet_tcp_uninit_data_in_cmds(), > and waits the inflight IO requests in nvmet_sq_destroy(). During wait > the inflight IO requests, the callback nvmet_tcp_queue_response() > is called from backend after IO complete, this leads a typical > Use-After-Free issue like this: > > BUG: kernel NULL pointer dereference, address: 0000000000000008 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 0 P4D 0 > Oops: 0000 [#1] PREEMPT SMP NOPTI > CPU: 14 PID: 207 Comm: kworker/14:1H Kdump: loaded Tainted: G E 6.0.0-rc2.bm.1-amd64 #12 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 > Workqueue: nvmet_tcp_wq nvmet_tcp_io_work [nvmet_tcp] > RIP: 0010:shash_ahash_digest+0x2b/0x110
This data access is specific to data-digest, because at this point there is no way for the data to be sent down the wire as the socket is shut down.
> Code: 1f 44 00 00 41 57 41 56 41 55 41 54 55 48 89 fd 53 48 89 f3 48 83 ec 08 44 8b 67 30 45 85 e4 74 1c 48 8b 57 38 b8 00 10 00 00 <44> 8b 7a 08 44 29 f8 39 42 0c 0f 46 42 0c 41 39 c4 76 43 48 8b 03 > RSP: 0018:ffffc900006e3dd8 EFLAGS: 00010206 > RAX: 0000000000001000 RBX: ffff888104ac1650 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffff888104ac1650 RDI: ffff888104ac1600 > RBP: ffff888104ac1600 R08: ffff8881073980c8 R09: ffff8881057798b8 > R10: 8080808080808080 R11: 0000000000000000 R12: 0000000000001000 > R13: 0000000000000000 R14: ffff88810601a1cc R15: ffff888107398000 > FS: 0000000000000000(0000) GS:ffff88823fd80000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000008 CR3: 000000010a8e8000 CR4: 0000000000350ee0 > Call Trace: > <TASK> > nvmet_tcp_io_work+0xa1c/0xb1c [nvmet_tcp] > ? __switch_to+0x106/0x420 > process_one_work+0x1ae/0x380 > ? process_one_work+0x380/0x380 > worker_thread+0x30/0x360 > ? process_one_work+0x380/0x380 > kthread+0xe6/0x110 > ? kthread_complete_and_exit+0x20/0x20 > ret_from_fork+0x1f/0x30 > > To fix this issue, free CMD buffers until all the inflight IO > complete. > > Signed-off-by: zhenwei pi <pizhenwei@bytedance.com> > --- > drivers/nvme/target/tcp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c > index dc3b4dc8fe08..2325246e3b4d 100644 > --- a/drivers/nvme/target/tcp.c > +++ b/drivers/nvme/target/tcp.c > @@ -1449,8 +1449,8 @@ static void nvmet_tcp_release_queue_work(struct work_struct *w) > /* stop accepting incoming data */ > queue->rcv_state = NVMET_TCP_RECV_ERR; > > - nvmet_tcp_uninit_data_in_cmds(queue); > nvmet_sq_destroy(&queue->nvme_sq); > + nvmet_tcp_uninit_data_in_cmds(queue);
We still need to uninit the nvmet request so nvmet_sq_destroy() can complete. Please separate nvmet_tcp_uninit_data_in_cmds to uninit and free potions, only the free should go after the sq_destroy.
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