Messages in this thread Patch in this message | | | From | zhenwei pi <> | Subject | [PATCH v2 1/1] nvmet-tcp: Fix NULL pointer dereference during release | Date | Wed, 31 Aug 2022 09:34:02 +0800 |
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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 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
Suggested by Sagi, separate nvmet_tcp_uninit_data_in_cmds() into two steps: uninit req <- new step 1 nvmet_sq_destroy(); free CMD buffers <- new step 2
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com> --- drivers/nvme/target/tcp.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-)
diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c index dc3b4dc8fe08..3bfd139b1434 100644 --- a/drivers/nvme/target/tcp.c +++ b/drivers/nvme/target/tcp.c @@ -1415,7 +1415,7 @@ static void nvmet_tcp_finish_cmd(struct nvmet_tcp_cmd *cmd) nvmet_tcp_free_cmd_buffers(cmd); } -static void nvmet_tcp_uninit_data_in_cmds(struct nvmet_tcp_queue *queue) +static void nvmet_tcp_uninit_req(struct nvmet_tcp_queue *queue) { struct nvmet_tcp_cmd *cmd = queue->cmds; int i; @@ -1423,14 +1423,27 @@ static void nvmet_tcp_uninit_data_in_cmds(struct nvmet_tcp_queue *queue) for (i = 0; i < queue->nr_cmds; i++, cmd++) { if (nvmet_tcp_need_data_in(cmd)) nvmet_req_uninit(&cmd->req); + } + + if (!queue->nr_cmds && nvmet_tcp_need_data_in(&queue->connect)) { + /* failed in connect */ + nvmet_req_uninit(&queue->connect.req); + } +} + +static void nvmet_tcp_uninit_data_in_cmds(struct nvmet_tcp_queue *queue) +{ + struct nvmet_tcp_cmd *cmd = queue->cmds; + int i; + for (i = 0; i < queue->nr_cmds; i++, cmd++) { nvmet_tcp_unmap_pdu_iovec(cmd); nvmet_tcp_free_cmd_buffers(cmd); } if (!queue->nr_cmds && nvmet_tcp_need_data_in(&queue->connect)) { - /* failed in connect */ - nvmet_tcp_finish_cmd(&queue->connect); + nvmet_tcp_unmap_pdu_iovec(&queue->connect); + nvmet_tcp_free_cmd_buffers(&queue->connect); } } @@ -1449,8 +1462,9 @@ 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_tcp_uninit_req(queue); nvmet_sq_destroy(&queue->nvme_sq); + nvmet_tcp_uninit_data_in_cmds(queue); cancel_work_sync(&queue->io_work); sock_release(queue->sock); nvmet_tcp_free_cmds(queue); -- 2.20.1
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