[kbuild-all] drivers/misc/habanalabs/common/command_submission.c:2457 hl_cs_poll_fences() error: we previously assumed 'fence' could be null (see line 2430)

Wednesday, 19 January 2022


tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   99613159ad749543621da8238acf1a122880144e
commit: e2558f0f84d85bfe2407b91d57798f133d8ad32a habanalabs: prevent wait if CS in
multi-CS list completed
config: s390-randconfig-m031-20220117
(https://download.01.org/0day-ci/archive/20220119/202201190048.qRDA3uFx-lk...)
compiler: s390-linux-gcc (GCC) 11.2.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp(a)intel.com&gt;
Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com&gt;

smatch warnings:
drivers/misc/habanalabs/common/command_submission.c:2457 hl_cs_poll_fences() error: we
previously assumed 'fence' could be null (see line 2430)

vim +/fence +2457 drivers/misc/habanalabs/common/command_submission.c

e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2383  static int hl_cs_poll_fences(struct multi_cs_data *mcs_data, struct
multi_cs_completion *mcs_compl)
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2384  {
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2385  	struct hl_fence **fence_ptr = mcs_data->fence_arr;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2386  	struct hl_device *hdev = mcs_data->ctx->hdev;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2387  	int i, rc, arr_len = mcs_data->arr_len;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2388  	u64 *seq_arr = mcs_data->seq_arr;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2389  	ktime_t max_ktime, first_cs_time;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2390  	enum hl_cs_wait_status status;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2391  
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2392  	memset(fence_ptr, 0, arr_len * sizeof(*fence_ptr));
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2393  
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2394  	/* get all fences under the same lock */
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2395  	rc = hl_ctx_get_fences(mcs_data->ctx, seq_arr, fence_ptr, arr_len);
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2396  	if (rc)
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2397  		return rc;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2398  
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2399  	/*
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2400  	 * re-initialize the completion here to handle 2 possible cases:
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2401  	 * 1. CS will complete the multi-CS prior clearing the completion. in
which
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2402  	 *    case the fence iteration is guaranteed to catch the CS
completion.
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2403  	 * 2. the completion will occur after re-init of the completion.
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2404  	 *    in which case we will wake up immediately in
wait_for_completion.
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2405  	 */
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2406  	reinit_completion(&mcs_compl->completion);
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2407  
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2408  	/*
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2409  	 * set to maximum time to verify timestamp is valid: if at the end
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2410  	 * this value is maintained- no timestamp was updated
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2411  	 */
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2412  	max_ktime = ktime_set(KTIME_SEC_MAX, 0);
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2413  	first_cs_time = max_ktime;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2414  
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2415  	for (i = 0; i < arr_len; i++, fence_ptr++) {
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2416  		struct hl_fence *fence = *fence_ptr;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2417  
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2418  		/*
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2419  		 * In order to prevent case where we wait until timeout even though a
CS associated
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2420  		 * with the multi-CS actually completed we do things in the below
order:
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2421  		 * 1. for each fence set it's QID map in the multi-CS completion
QID map. This way
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2422  		 *    any CS can, potentially, complete the multi CS for the specific
QID (note
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2423  		 *    that once completion is initialized, calling complete* and then
wait on the
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2424  		 *    completion will cause it to return at once)
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2425  		 * 2. only after allowing multi-CS completion for the specific QID we
check whether
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2426  		 *    the specific CS already completed (and thus the wait for
completion part will
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2427  		 *    be skipped). if the CS not completed it is guaranteed that
completing CS will
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2428  		 *    wake up the completion.
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2429  		 */
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07 @2430  		if (fence)
                                                                                          
                         ^^^^^


e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2431  			mcs_compl->stream_master_qid_map |=
fence->stream_master_qid_map;
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2432  
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2433  		/*
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2434  		 * function won't sleep as it is called with timeout 0 (i.e.
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2435  		 * poll the fence)
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2436  		 */
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2437  		rc = hl_wait_for_fence(mcs_data->ctx, seq_arr[i], fence,
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2438  						&status, 0, NULL);
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2439  		if (rc) {
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2440  			dev_err(hdev->dev,
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2441  				"wait_for_fence error :%d for CS seq %llu\n",
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2442  								rc, seq_arr[i]);
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2443  			break;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2444  		}
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2445  
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2446  		switch (status) {
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2447  		case CS_WAIT_STATUS_BUSY:
e2558f0f84d85b drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-12-07  2448  			/* CS did not finished, QID to wait on already stored */
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2449  			break;
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2450  		case CS_WAIT_STATUS_COMPLETED:
ea6eb91c09cd4f drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-03  2451  			/*
ea6eb91c09cd4f drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-03  2452  			 * Using mcs_handling_done to avoid possibility of mcs_data
ea6eb91c09cd4f drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-03  2453  			 * returns to user indicating CS completed before it finished
ea6eb91c09cd4f drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-03  2454  			 * all of its mcs handling, to avoid race the next time the
ea6eb91c09cd4f drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-03  2455  			 * user waits for mcs.
ea6eb91c09cd4f drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-03  2456  			 */
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12 @2457  			if (!fence->mcs_handling_done)
                                                                                          
                                  ^^^^^^^
Unchecked derereference

b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2458  				break;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2459  
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2460  			mcs_data->completion_bitmap |= BIT(i);
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2461  			/*
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2462  			 * For all completed CSs we take the earliest timestamp.
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2463  			 * For this we have to validate that the timestamp is
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2464  			 * earliest of all timestamps so far.
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2465  			 */
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2466  			if (mcs_data->update_ts &&
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2467  					(ktime_compare(fence->timestamp, first_cs_time) < 0))
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2468  				first_cs_time = fence->timestamp;
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2469  			break;
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2470  		case CS_WAIT_STATUS_GONE:
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2471  			mcs_data->update_ts = false;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2472  			mcs_data->gone_cs = true;
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2473  			/*
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2474  			 * It is possible to get an old sequence numbers from user
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2475  			 * which related to already completed CSs and their fences
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2476  			 * already gone. In this case, CS set as completed but
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2477  			 * no need to consider its QID for mcs completion.
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2478  			 */
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2479  			mcs_data->completion_bitmap |= BIT(i);
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2480  			break;
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2481  		default:
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2482  			dev_err(hdev->dev, "Invalid fence status\n");
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2483  			return -EINVAL;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2484  		}
b2faac3887df87 drivers/misc/habanalabs/common/command_submission.c Dani Liberman
2021-10-12  2485  
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2486  	}
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2487  
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2488  	hl_fences_put(mcs_data->fence_arr, arr_len);
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2489  
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2490  	if (mcs_data->update_ts &&
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2491  			(ktime_compare(first_cs_time, max_ktime) != 0))
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2492  		mcs_data->timestamp = ktime_to_ns(first_cs_time);
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2493  
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2494  	return rc;
215f0c1775d550 drivers/misc/habanalabs/common/command_submission.c Ohad Sharabi 
2021-06-14  2495  }

---
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[kbuild-all] drivers/misc/habanalabs/common/command_submission.c:2457 hl_cs_poll_fences() error: we previously assumed 'fence' could be null (see line 2430)