linux-kernel - [PATCH] mmc: dw_mmc: Dont wait for DRTO on Write RSP error

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 16 Sep 2021 05:59:19 +0000
From:   Christian Löhle <CLoehle@...erstone.com>
To:     "jh80.chung@...sung.com" <jh80.chung@...sung.com>,
        "ulf.hansson@...aro.org" <ulf.hansson@...aro.org>,
        Christian Löhle <CLoehle@...erstone.com>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] mmc: dw_mmc: Dont wait for DRTO on Write RSP error

Only wait for DRTO on reads, otherwise the driver hangs.

The driver prevents sending CMD12 on response errors like CRCs.
According to the comment this is because some cards have problems
with this during the UHS tuning sequence.
Unfortunately this workaround currently also applies for any command
with data.
On reads this will set the drto timer which then triggers after a while.
On writes this will not set any timer and the tasklet will not be
scheduled again.
I cannot attest for the UHS workarounds need, but even if so, it should
at most apply to reads.
I have observed many hangs when CMD25 response contained a CRC error.
This patch fixes this without touching the actual UHS tuning workaround.

Signed-off-by: Christian Loehle <cloehle@...erstone.com>
---
 drivers/mmc/host/dw_mmc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 6578cc64ae9e..22cf13dc799b 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -2081,7 +2081,8 @@ static void dw_mci_tasklet_func(struct tasklet_struct *t)
 				 * delayed. Allowing the transfer to take place
 				 * avoids races and keeps things simple.
 				 */
-				if (err != -ETIMEDOUT) {
+				if (err != -ETIMEDOUT &&
+				    host->dir_status == DW_MCI_RECV_STATUS) {
 					state = STATE_SENDING_DATA;
 					continue;
 				}
-- 
2.32.0
Hyperstone GmbH | Line-Eid-Strasse 3 | 78467 Konstanz
Managing Directors: Dr. Jan Peter Berns.
Commercial register of local courts: Freiburg HRB381782