linux-kernel - [PATCH v3] scsi: ufs: core: fix racing issue during ufshcd_mcq

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Message-Id: <20231121071128.7743-1-hy50.seo@samsung.com>
Date:   Tue, 21 Nov 2023 16:11:28 +0900
From:   SEO HOYOUNG <hy50.seo@...sung.com>
To:     linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
        alim.akhtar@...sung.com, avri.altman@....com, jejb@...ux.ibm.com,
        martin.petersen@...cle.com, beanhuo@...ron.com, bvanassche@....org,
        kwangwon.min@...sung.com, kwmad.kim@...sung.com,
        sh425.lee@...sung.com, sc.suh@...sung.com,
        quic_nguyenb@...cinc.com, cpgs@...sung.com, grant.jung@...sung.com,
        junwoo80.lee@...sung.com
Cc:     SEO HOYOUNG <hy50.seo@...sung.com>
Subject: [PATCH v3] scsi: ufs: core: fix racing issue during
 ufshcd_mcq_abort

If cq complete irq raise during abort processing,
the command has already been complete.
So could not get utag to erase cmd like below log.
Because the cmd that was handling abort has already been completed

ufshcd_try_to_abort_task: cmd pending in the device. tag = 25
Unable to handle kernel NULL pointer dereference at virtual address
0000000000000194
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0

pc : blk_mq_unique_tag+0x8/0x14
lr : ufshcd_mcq_sq_cleanup+0x6c/0x1b8
sp : ffffffc03e3b3b10
x29: ffffffc03e3b3b10 x28: 0000000000000001 x27: ffffff8830b34f68
x26: ffffff8830b34f6c x25: ffffff8830b34040 x24: 0000000000000000
x23: 0000000000000f18 x22: ffffffc03e3b3bb8 x21: 0000000000000019
x20: 0000000000000019 x19: ffffff8830b309b0 x18: ffffffc00a1b5380
x17: 00000000529c6ef0 x16: 00000000529c6ef0 x15: 0000000000000000
x14: 0000000000000010 x13: 0000000000000032 x12: 0000001169e8a5bc
x11: 0000000000000001 x10: ffffff885dfc1588 x9 : 0000000000000019
x8 : 0000000000000000 x7 : 0000000000000001 x6 : fffffffdef706f28
x5 : 000000000000283d x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000003 x1 : 0000000000000019 x0 : ffffff8855781200
Call trace:
blk_mq_unique_tag+0x8/0x14
ufshcd_clear_cmd+0x34/0x118
ufshcd_try_to_abort_task+0x1c4/0x4b0
ufshcd_err_handler+0x8d0/0xd24
process_one_work+0x1e4/0x43c
worker_thread+0x25c/0x430
kthread+0x104/0x1d4
ret_from_fork+0x10/0x20

v1 -> v2: fix build error

v2 -> v3: move to ufshcd_mcq_sq_cleanup() function

Bart said that lrbp->cmd could be changed before ufshcd_clear_cmd() was
called, so lrbp->cmd check was moved to ufshcd_clear_cmd().
In the case of legacy mode, spin_lock is used to protect before clear cmd,
but spin_lock cannot be used due to mcq mode, so it is necessary to check
the status of lrbp->cmd.

Change-Id: Id8412190e60286d00a30820591566835cefbf47e
Signed-off-by: SEO HOYOUNG <hy50.seo@...sung.com>
---
 drivers/ufs/core/ufs-mcq.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/ufs/core/ufs-mcq.c b/drivers/ufs/core/ufs-mcq.c
index 2ba8ec254dce..deb6dac724c8 100644
--- a/drivers/ufs/core/ufs-mcq.c
+++ b/drivers/ufs/core/ufs-mcq.c
@@ -507,6 +507,10 @@ int ufshcd_mcq_sq_cleanup(struct ufs_hba *hba, int task_tag)
 	if (hba->quirks & UFSHCD_QUIRK_MCQ_BROKEN_RTC)
 		return -ETIMEDOUT;
 
+	if (!ufshcd_cmd_inflight(cmd) ||
+	    test_bit(SCMD_STATE_COMPLETE, &cmd->state))
+		return 0;
+
 	if (task_tag != hba->nutrs - UFSHCD_NUM_RESERVED) {
 		if (!cmd)
 			return -EINVAL;
-- 
2.26.0