From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BF1BA5208B3; Wed, 30 Sep 2026 17:45:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790790351; cv=none; b=K5Bm1S73G3OZRy/qSBphbjCAb6/sNDtLZLcluGF2OQ2Hav+aKTwvjQy0DI0Q45keB/vbWBhxPWR6Q/DNqFPIos+dNJymUq6yEYz+HxIKNua9yBPb7dkfDb1ateLpTBx3zkZdIBQspuVBihQgIpUQShPhsYGxLipZTsJCyIK8KrU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790790351; c=relaxed/simple; bh=aWlbB2mS7Kl5TxIEnVjcroUvtC3zLJBnJDccBcU/gIU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Y6am3VLfjD4619qaPVVXdsQNgFduYfPFtT1GOvlqume+qi9nkcNnmDvU+s0AnSRE1R8NB7IpghKVEPHplydyVHfIAjFp5BJT+2LayRNwZTibwwFHI4y8IGL1cfwRKmDYVjnWRv1QmSzBmvf3bLmnC5RXa2LY2sBS2Gb+Ox8MYio= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ezgDBXnw; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ezgDBXnw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24DA31F000FF; Wed, 30 Sep 2026 17:45:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790790349; bh=upHB7jV3elYQrgKHHzqAFAVch8VbjAqnoS4rb5+k/hU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ezgDBXnwk/gZrysXjjQAL53E4MhGtEqUt1AHUjJE0TG3eRfRlFFHJDubomWs76mxt hbiukKZuEx97CPmsQ4/ypKuuL6T+KJ04DO7lYbZQhNnJChEWGB/pxqsoHONvk48K6c cIu8UZ7/6gmqg6WuwZWSRpnknfYh9qWylOVZ3be0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yibo Tan , Guenter Roeck , Sasha Levin Subject: [PATCH 6.12 799/877] hwmon: (pwm-fan) Stop RPM timer before freeing tach data Date: Wed, 30 Sep 2026 17:28:30 +0200 Message-ID: <20260930152431.958447047@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152414.738996857@linuxfoundation.org> References: <20260930152414.738996857@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yibo Tan [ Upstream commit 26d5ff79768548efb1e604bb6e8697c101e06269 ] sample_timer() rearms the RPM timer and accesses the devm-managed ctx->tachs and ctx->pulses_per_revolution arrays. The cleanup action which stops the timer is registered before those arrays are allocated. Since devres releases entries in reverse order, driver detach can free the arrays before pwm_fan_cleanup() shuts down the timer. A timer expiry in that window accesses the freed tach data. With a KASAN kernel, a test-only kprobe delayed entry to pwm_fan_cleanup() while normal sysfs unbind ran. Each of three runs reported three four-byte reads and two four-byte writes in sample_timer() after its backing devm allocations had been freed. The helper did not invoke the timer callback, cleanup actions or free functions. With the fix, three matching unbind runs completed without KASAN, BUG, WARNING, Oops or panic. Instrumentation confirmed that timer retirement completed before the first timer backing allocation was released. Split timer retirement from the power cleanup and register its devres action after the timer backing data and IRQ actions are installed. This preserves the early power rollback action while ensuring the timer is retired before its backing data is released. Use timer_shutdown_sync() because the callback can rearm itself. Fixes: 01695410d452 ("hwmon: (pwm-fan) Store tach data separately") Cc: stable@vger.kernel.org Assisted-by: Codex:GPT-5 Signed-off-by: Yibo Tan Link: https://patch.msgid.link/20260911071809.130151-1-lhfff@tju.edu.cn Signed-off-by: Guenter Roeck [ Adapted cleanup changes to the older pwm_fan_cleanup() using del_timer_sync() without pwm_shutdown handling. ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/hwmon/pwm-fan.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) --- a/drivers/hwmon/pwm-fan.c +++ b/drivers/hwmon/pwm-fan.c @@ -466,12 +466,18 @@ static void pwm_fan_cleanup(void *__ctx) { struct pwm_fan_ctx *ctx = __ctx; - del_timer_sync(&ctx->rpm_timer); /* Switch off everything */ ctx->enable_mode = pwm_disable_reg_disable; pwm_fan_power_off(ctx, true); } +static void pwm_fan_timer_cleanup(void *__ctx) +{ + struct pwm_fan_ctx *ctx = __ctx; + + timer_shutdown_sync(&ctx->rpm_timer); +} + static int pwm_fan_probe(struct platform_device *pdev) { struct thermal_cooling_device *cdev; @@ -614,6 +620,10 @@ static int pwm_fan_probe(struct platform } if (ctx->tach_count > 0) { + ret = devm_add_action_or_reset(dev, pwm_fan_timer_cleanup, ctx); + if (ret) + return ret; + ctx->sample_start = ktime_get(); mod_timer(&ctx->rpm_timer, jiffies + HZ); @@ -655,6 +665,7 @@ static void pwm_fan_shutdown(struct plat { struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); + pwm_fan_timer_cleanup(ctx); pwm_fan_cleanup(ctx); }