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scsi: ufs: core: Fix race between force complete and ISR

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While error handler force complete command (Thread A) and completion IRQ
raising (Thread B) of the same command, it may cause race condition.

Below is racing step (from 1 to 6):
	ufshcd_mcq_compl_pending_transfer (Thread A)
1	if (cmd && !test_bit(SCMD_STATE_COMPLETE, &cmd->state)) {
5		spin_lock_irqsave(&hwq->cq_lock, flags);	// wait lock release
		set_host_byte(cmd, DID_REQUEUE);
6		ufshcd_release_scsi_cmd(hba, lrbp);	// access null pointer
		scsi_done(cmd);
		spin_unlock_irqrestore(&hwq->cq_lock, flags);
	}

	ufshcd_mcq_poll_cqe_lock (Thread B)
2	spin_lock_irqsave(&hwq->cq_lock, flags);
	 ufshcd_mcq_poll_cqe_nolock()
	  ufshcd_compl_one_cqe()
3	   ufshcd_release_scsi_cmd()	// lrbp->cmd = NULL;
4	spin_unlock_irqrestore(&hwq->cq_lock, flags);

Signed-off-by: Alice Chao <alice.chao@mediatek.com>
Link: https://lore.kernel.org/r/20231024084324.12197-1-alice.chao@mediatek.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Alice Chao 2023-10-24 16:43:21 +08:00 committed by Martin K. Petersen
parent f2d79aa16a
commit a5181c8955
1 changed files with 2 additions and 2 deletions
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4
drivers/ufs/core/ufshcd.c
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@ -5615,13 +5615,13 @@ static void ufshcd_mcq_compl_pending_transfer(struct ufs_hba *hba,
* For those cmds of which the cqes are not present
* in the cq, complete them explicitly.
*/
spin_lock_irqsave(&hwq->cq_lock, flags);
if (cmd && !test_bit(SCMD_STATE_COMPLETE, &cmd->state)) {
spin_lock_irqsave(&hwq->cq_lock, flags);
set_host_byte(cmd, DID_REQUEUE);
ufshcd_release_scsi_cmd(hba, lrbp);
scsi_done(cmd);
spin_unlock_irqrestore(&hwq->cq_lock, flags);
}
spin_unlock_irqrestore(&hwq->cq_lock, flags);
} else {
ufshcd_mcq_poll_cqe_lock(hba, hwq);
}