[PATCH 1/1] mmc: cqhci: fix random crash when remove mmc module

[Frank Li]

[ 6684.493350] Unable to handle kernel paging request at virtual address ffff800011c5b0f0
[ 6684.498531] mmc0: card 0001 removed
[ 6684.501556] Mem abort info:
[ 6684.509681]   ESR = 0x96000047
[ 6684.512786]   EC = 0x25: DABT (current EL), IL = 32 bits
[ 6684.518394]   SET = 0, FnV = 0
[ 6684.521707]   EA = 0, S1PTW = 0
[ 6684.524998] Data abort info:
[ 6684.528236]   ISV = 0, ISS = 0x00000047
[ 6684.532986]   CM = 0, WnR = 1
[ 6684.536129] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000081b22000
[ 6684.543923] [ffff800011c5b0f0] pgd=00000000bffff003, p4d=00000000bffff003, pud=00000000bfffe003, pmd=00000000900e1003, pte=0000000000000000
[ 6684.557915] Internal error: Oops: 96000047 [#1] PREEMPT SMP
[ 6684.564240] Modules linked in: sdhci_esdhc_imx(-) sdhci_pltfm sdhci cqhci mmc_block mmc_core fsl_jr_uio caam_jr caamkeyblob_desc caamhash_desc caamalg_desc crypto_engine rng_core authenc libdes crct10dif_ce flexcan can_dev caam error [last unloaded: mmc_core]
[ 6684.587281] CPU: 0 PID: 79138 Comm: kworker/0:3H Not tainted 5.10.9-01410-g3ba33182767b-dirty #10
[ 6684.596160] Hardware name: Freescale i.MX8DXL EVK (DT)
[ 6684.601320] Workqueue: kblockd blk_mq_run_work_fn

[ 6684.606094] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--)
[ 6684.612286] pc : cqhci_request+0x148/0x4e8 [cqhci]
^GMessage from syslogd@  at Thu Jan  1 01:51:24 1970 ...[ 6684.617085] lr : cqhci_request+0x314/0x4e8 [cqhci]
[ 6684.626734] sp : ffff80001243b9f0
[ 6684.630049] x29: ffff80001243b9f0 x28: ffff00002c3dd000
[ 6684.635367] x27: 0000000000000001 x26: 0000000000000001
[ 6684.640690] x25: ffff00002c451000 x24: 000000000000000f
[ 6684.646007] x23: ffff000017e71c80 x22: ffff00002c451000
[ 6684.651326] x21: ffff00002c0f3550 x20: ffff00002c0f3550
[ 6684.656651] x19: ffff000017d46880 x18: ffff00002cea1500
[ 6684.661977] x17: 0000000000000000 x16: 0000000000000000
[ 6684.667294] x15: 000001ee628e3ed1 x14: 0000000000000278
[ 6684.672610] x13: 0000000000000001 x12: 0000000000000001
[ 6684.677927] x11: 0000000000000000 x10: 0000000000000000
[ 6684.683243] x9 : 000000000000002b x8 : 0000000000001000
[ 6684.688560] x7 : 0000000000000010 x6 : ffff00002c0f3678
[ 6684.693886] x5 : 000000000000000f x4 : ffff800011c5b000
[ 6684.699211] x3 : 000000000002d988 x2 : 0000000000000008
[ 6684.704537] x1 : 00000000000000f0 x0 : 0002d9880008102f
[ 6684.709854] Call trace:
[ 6684.712313]  cqhci_request+0x148/0x4e8 [cqhci]
[ 6684.716803]  mmc_cqe_start_req+0x58/0x68 [mmc_core]
[ 6684.721698]  mmc_blk_mq_issue_rq+0x460/0x810 [mmc_block]
[ 6684.727018]  mmc_mq_queue_rq+0x118/0x2b0 [mmc_block]

cqhci_request was called after cqhci_disable.

cqhci_disable                                 cqhci_request
{                                             {
	dmam_free_coherent();  (1) free
                                                  if(!cq_host->enable)
                                                       return
				         (2) pass check here
	cq_host->enable = false;

                                                  task_desc= get_desc(cq_host,tag);
                                                             ^^^^ crash here
                                         (3) access memory which is already free

}                                             }

Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
 drivers/mmc/host/cqhci-core.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/cqhci-core.c b/drivers/mmc/host/cqhci-core.c
index 93b0432bb601..36d292261e50 100644
--- a/drivers/mmc/host/cqhci-core.c
+++ b/drivers/mmc/host/cqhci-core.c
@@ -389,6 +389,7 @@ static void cqhci_off(struct mmc_host *mmc)
 static void cqhci_disable(struct mmc_host *mmc)
 {
 	struct cqhci_host *cq_host = mmc->cqe_private;
+	unsigned long flags;
 
 	if (!cq_host->enabled)
 		return;
@@ -397,6 +398,11 @@ static void cqhci_disable(struct mmc_host *mmc)
 
 	__cqhci_disable(cq_host);
 
+	/* need wait for cqhci_request finish before free memory */
+	spin_lock_irqsave(&cq_host->lock, flags);
+	cq_host->enabled = false;
+	spin_unlock_irqrestore(&cq_host->lock, flags);
+
 	dmam_free_coherent(mmc_dev(mmc), cq_host->data_size,
 			   cq_host->trans_desc_base,
 			   cq_host->trans_desc_dma_base);
@@ -408,7 +414,6 @@ static void cqhci_disable(struct mmc_host *mmc)
 	cq_host->trans_desc_base = NULL;
 	cq_host->desc_base = NULL;
 
-	cq_host->enabled = false;
 }
 
 static void cqhci_prep_task_desc(struct mmc_request *mrq,
@@ -612,6 +617,13 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 			cq_host->ops->enable(mmc);
 	}
 
+	spin_lock_irqsave(&cq_host->lock, flags);
+	if (!cq_host->enabled) {
+		pr_err("%s: cqhci: not enabled\n", mmc_hostname(mmc));
+		err = -EINVAL;
+		goto out_unlock;
+	}
+
 	if (mrq->data) {
 		cqhci_prep_task_desc(mrq, cq_host, tag);
 
@@ -619,14 +631,12 @@ static int cqhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 		if (err) {
 			pr_err("%s: cqhci: failed to setup tx desc: %d\n",
 			       mmc_hostname(mmc), err);
-			return err;
+			goto out_unlock;
 		}
 	} else {
 		cqhci_prep_dcmd_desc(mmc, mrq);
 	}
 
-	spin_lock_irqsave(&cq_host->lock, flags);
-
 	if (cq_host->recovery_halt) {
 		err = -EBUSY;
 		goto out_unlock;
-- 
2.25.1