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([163.239.22.29]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3b101bc4586sm1246851a91.2.2026.11.06.21.32.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 Nov 2026 21:32:32 -0800 (PST) From: hyunjungg To: Binbin Zhou , Chong Qiao , Lee Jones Cc: mfd@lists.linux.dev, linux-kernel@vger.kernel.org, Hyunjung Ko , stable@vger.kernel.org Subject: [PATCH] mfd: ls2kbmc: cancel the reset work before the driver data is freed Date: Sat, 7 Nov 2026 14:32:18 +0900 Message-ID: <20261107053218.3326443-1-hj351016@gmail.com> X-Mailer: git-send-email 2.43.0 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Hyunjung Ko ls2k_bmc_init() INIT_WORK()s ddata->bmc_reset_work (ls2k_bmc_events_fn) and requests two device-managed interrupts (ls2k_bmc_interrupt) that schedule_work(&ddata->bmc_reset_work). The work handler dereferences ddata via container_of(). ddata is devm_kzalloc()'d, so devres frees it when the device is unbound. Nothing cancels bmc_reset_work: free_irq() (run by devres) only waits for the interrupt handler to finish, not for a work item it has already queued. If a BMC reset interrupt fires shortly before unbind, the queued ls2k_bmc_events_fn() can run after ddata has been freed -> use-after-free. Register the work for device-managed cancellation with devm_work_autocancel(), before the devm_request_irq() calls that arm it, so devres (LIFO) frees the interrupts first, then cancels the work, and only then frees ddata. Found by code review; not reproduced (needs Loongson-2K BMC hardware and a reset interrupt racing driver unbind). Fixes: d952bba3fbb5 ("mfd: ls2kbmc: Add Loongson-2K BMC reset function support") Cc: stable@vger.kernel.org Signed-off-by: Hyunjung Ko --- drivers/mfd/ls2k-bmc-core.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/mfd/ls2k-bmc-core.c b/drivers/mfd/ls2k-bmc-core.c index 408056b..c44291e 100644 --- a/drivers/mfd/ls2k-bmc-core.c +++ b/drivers/mfd/ls2k-bmc-core.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -371,7 +372,10 @@ static int ls2k_bmc_init(struct ls2k_bmc_ddata *ddata) ls2k_bmc_save_pci_data(pdev, ddata); - INIT_WORK(&ddata->bmc_reset_work, ls2k_bmc_events_fn); + ret = devm_work_autocancel(ddata->dev, &ddata->bmc_reset_work, + ls2k_bmc_events_fn); + if (ret) + return ret; ret = devm_request_irq(&pdev->dev, pdev->irq, ls2k_bmc_interrupt, IRQF_SHARED | IRQF_TRIGGER_FALLING, "ls2kbmc pcie", ddata); -- 2.43.0