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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>
Subject: [PATCH 5.17 049/225] bus: fsl-mc-msi: Fix MSI descriptor mutex lock for msi_first_desc()
Date:   Wed,  4 May 2022 18:44:47 +0200
Message-Id: <20220504153114.491213159@linuxfoundation.org>
In-Reply-To: <20220504153110.096069935@linuxfoundation.org>
References: <20220504153110.096069935@linuxfoundation.org>
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From: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>

commit c7d2f89fea26c84d5accc55d9976dd7e5305e63a upstream.

Commit e8604b1447b4 introduced a call to the helper function
msi_first_desc(), which needs MSI descriptor mutex lock before
call. However, the required mutex lock was not added. This results in
lockdep assertion:

 WARNING: CPU: 4 PID: 119 at kernel/irq/msi.c:274 msi_first_desc+0xd0/0x10c
  msi_first_desc+0xd0/0x10c
  fsl_mc_msi_domain_alloc_irqs+0x7c/0xc0
  fsl_mc_populate_irq_pool+0x80/0x3cc

Fix this by adding the mutex lock and unlock around the function call.

Fixes: e8604b1447b4 ("bus: fsl-mc-msi: Simplify MSI descriptor handling")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220412075636.755454-1-shinichiro.kawasaki@wdc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/bus/fsl-mc/fsl-mc-msi.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/fsl-mc/fsl-mc-msi.c b/drivers/bus/fsl-mc/fsl-mc-msi.c
index 5e0e4393ce4d..0cfe859a4ac4 100644
--- a/drivers/bus/fsl-mc/fsl-mc-msi.c
+++ b/drivers/bus/fsl-mc/fsl-mc-msi.c
@@ -224,8 +224,12 @@ int fsl_mc_msi_domain_alloc_irqs(struct device *dev,  unsigned int irq_count)
 	if (error)
 		return error;
 
+	msi_lock_descs(dev);
 	if (msi_first_desc(dev, MSI_DESC_ALL))
-		return -EINVAL;
+		error = -EINVAL;
+	msi_unlock_descs(dev);
+	if (error)
+		return error;
 
 	/*
 	 * NOTE: Calling this function will trigger the invocation of the
-- 
2.36.0