linux-kernel - [PATCH AUTOSEL 4.14 5/9] scsi: ufs: Make sure clk scaling happens only when HBA is runtime ACTIVE

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

Message-Id: <20201203133031.931763-5-sashal@kernel.org>
Date:   Thu,  3 Dec 2020 08:30:27 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Can Guo <cang@...eaurora.org>,
        Stanley Chu <stanley.chu@...iatek.com>,
        "Martin K . Petersen" <martin.petersen@...cle.com>,
        Sasha Levin <sashal@...nel.org>, linux-scsi@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org
Subject: [PATCH AUTOSEL 4.14 5/9] scsi: ufs: Make sure clk scaling happens only when HBA is runtime ACTIVE

From: Can Guo <cang@...eaurora.org>

[ Upstream commit 73cc291c270248567245f084dcdf5078069af6b5 ]

If someone plays with the UFS clk scaling devfreq governor through sysfs,
ufshcd_devfreq_scale may be called even when HBA is not runtime ACTIVE.
This can lead to unexpected error. We cannot just protect it by calling
pm_runtime_get_sync() because that may cause a race condition since HBA
runtime suspend ops need to suspend clk scaling. To fix this call
pm_runtime_get_noresume() and check HBA's runtime status. Only proceed if
HBA is runtime ACTIVE, otherwise just bail.

governor_store
 devfreq_performance_handler
  update_devfreq
   devfreq_set_target
    ufshcd_devfreq_target
     ufshcd_devfreq_scale

Link: https://lore.kernel.org/r/1600758548-28576-1-git-send-email-cang@codeaurora.org
Reviewed-by: Stanley Chu <stanley.chu@...iatek.com>
Signed-off-by: Can Guo <cang@...eaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/scsi/ufs/ufshcd.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index a3a3ee6e2a002..342e086e41991 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1215,8 +1215,15 @@ static int ufshcd_devfreq_target(struct device *dev,
 	}
 	spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
 
+	pm_runtime_get_noresume(hba->dev);
+	if (!pm_runtime_active(hba->dev)) {
+		pm_runtime_put_noidle(hba->dev);
+		ret = -EAGAIN;
+		goto out;
+	}
 	start = ktime_get();
 	ret = ufshcd_devfreq_scale(hba, scale_up);
+	pm_runtime_put(hba->dev);
 
 	trace_ufshcd_profile_clk_scaling(dev_name(hba->dev),
 		(scale_up ? "up" : "down"),
-- 
2.27.0