From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Ruoyu Wang <ruoyuw560@gmail.com>,
	Alex Elder <elder@riscstar.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.12 1251/1376] net: ipa: balance runtime PM reference on remove error
Date: Sat, 12 Sep 2026 09:01:17 +0200
Message-ID: <20260912065635.424202547@linuxfoundation.org>
In-Reply-To: <20260912065607.535295758@linuxfoundation.org>
References: <20260912065607.535295758@linuxfoundation.org>
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6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ruoyu Wang <ruoyuw560@gmail.com>

[ Upstream commit 6b9eaa61ff2df63c6eb35d5cd025e2cef0861d76 ]

ipa_remove() takes a runtime PM reference before accessing IPA hardware
during teardown. If a concurrent modem start or stop keeps
ipa_modem_stop() busy across both attempts, the callback intentionally
returns without releasing the remaining resources because proceeding
with teardown could crash. That return also skips the matching
pm_runtime_put_noidle(), leaving the callback's usage-count reference
held.

Drop only this runtime PM reference before returning.
pm_runtime_put_noidle() does not request an idle transition, so the
hardware and resources retained on this exceptional path remain
untouched while the usage count stays balanced.

This issue was found by a static analysis checker and confirmed by
manual source review.

Fixes: 923a6b698447 ("net: ipa: get clock in ipa_probe()")
Signed-off-by: Ruoyu Wang <ruoyuw560@gmail.com>
Reviewed-by: Alex Elder <elder@riscstar.com>
Link: https://patch.msgid.link/20260815151737.3758320-1-ruoyuw560@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ipa/ipa_main.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ipa/ipa_main.c b/drivers/net/ipa/ipa_main.c
index f374a590d1c5e..aa48ee2c91576 100644
--- a/drivers/net/ipa/ipa_main.c
+++ b/drivers/net/ipa/ipa_main.c
@@ -974,12 +974,12 @@ static void ipa_remove(struct platform_device *pdev)
 		}
 		if (ret) {
 			/*
-			 * Not cleaning up here properly might also yield a
-			 * crash later on. As the device is still unregistered
-			 * in this case, this might even yield a crash later on.
+			 * Continuing teardown after failing to stop the modem
+			 * could crash, so leave the remaining resources allocated.
 			 */
 			dev_err(dev, "Failed to stop modem (%pe), leaking resources\n",
 				ERR_PTR(ret));
+			pm_runtime_put_noidle(dev);
 			return;
 		}
 
-- 
2.53.0