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[36.234.53.90]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-86153728c37sm3292257b3a.46.2026.09.06.06.16.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 06 Sep 2026 06:16:36 -0700 (PDT) From: Hank Yang To: marvin24@gmx.de Cc: gregkh@linuxfoundation.org, ac100@lists.launchpad.net, linux-tegra@vger.kernel.org, linux-staging@lists.linux.dev, Hank Yang Subject: [PATCH] staging: nvec: fix race between power-off callback and driver removal Date: Sun, 6 Sep 2026 21:15:29 +0800 Message-ID: <20260906131529.11422-1-s950343@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit tegra_nvec_remove() checks pm_power_off against nvec_power_off and then clears it in two separate steps: if (pm_power_off == nvec_power_off) pm_power_off = NULL; If a shutdown is triggered between the check and the clear, the system's power-off path can call nvec_power_off() while tegra_nvec_remove() is concurrently tearing down the device (freeing resources via mfd_remove_devices(), cancel_work_sync(), etc.), leading to a use-after-free on nvec_power_handle. Use cmpxchg() to make the check-and-clear atomic, closing this race window. Compile-tested (ARM, tegra_defconfig) only; I don't have access to Tegra Paz00 hardware to test this at runtime. Assisted-by: Claude:claude-sonnet-5 Signed-off-by: Hank Yang --- drivers/staging/nvec/nvec.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c index 41cbdfdc1da6..b9ebfdf46002 100644 --- a/drivers/staging/nvec/nvec.c +++ b/drivers/staging/nvec/nvec.c @@ -906,8 +906,7 @@ static void tegra_nvec_remove(struct platform_device *pdev) nvec_unregister_notifier(nvec, &nvec->nvec_status_notifier); cancel_work_sync(&nvec->rx_work); cancel_work_sync(&nvec->tx_work); - if (pm_power_off == nvec_power_off) - pm_power_off = NULL; + cmpxchg(&pm_power_off, nvec_power_off, NULL); } #ifdef CONFIG_PM_SLEEP -- 2.43.0