From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 DF059611B for ; Sun, 28 May 2023 19:38:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C937C433D2; Sun, 28 May 2023 19:38:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1685302687; bh=VRQuVpm7GwZtd9sZnDN6atDLPlzNL3RGcWsWnDKH6Zk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GFZgPft6c3+ln1szGmaLwMS42wF71U5uVtUkUAjI1yg499cDgSDDwpEcE90FjeHMf nWybxn9ajD8HI8UbCQ9JtrTk5tDxXc0sJwFgTQNA1BXKHiHjW3QmywC7abiaBYPZEd sKo2R0j0usDn855RYjBemnt7qcY1yFzBFV691rSU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hans de Goede , Sebastian Reichel Subject: [PATCH 6.1 077/119] power: supply: bq27xxx: Fix poll_interval handling and races on remove Date: Sun, 28 May 2023 20:11:17 +0100 Message-Id: <20230528190838.078666449@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230528190835.386670951@linuxfoundation.org> References: <20230528190835.386670951@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Hans de Goede commit c00bc80462afc7963f449d7f21d896d2f629cacc upstream. Before this patch bq27xxx_battery_teardown() was setting poll_interval = 0 to avoid bq27xxx_battery_update() requeuing the delayed_work item. There are 2 problems with this: 1. If the driver is unbound through sysfs, rather then the module being rmmod-ed, this changes poll_interval unexpectedly 2. This is racy, after it being set poll_interval could be changed before bq27xxx_battery_update() checks it through /sys/module/bq27xxx_battery/parameters/poll_interval Fix this by added a removed attribute to struct bq27xxx_device_info and using that instead of setting poll_interval to 0. There also is another poll_interval related race on remove(), writing /sys/module/bq27xxx_battery/parameters/poll_interval will requeue the delayed_work item for all devices on the bq27xxx_battery_devices list and the device being removed was only removed from that list after cancelling the delayed_work item. Fix this by moving the removal from the bq27xxx_battery_devices list to before cancelling the delayed_work item. Fixes: 8cfaaa811894 ("bq27x00_battery: Fix OOPS caused by unregistring bq27x00 driver") Signed-off-by: Hans de Goede Signed-off-by: Sebastian Reichel Signed-off-by: Greg Kroah-Hartman --- drivers/power/supply/bq27xxx_battery.c | 22 +++++++++------------- include/linux/power/bq27xxx_battery.h | 1 + 2 files changed, 10 insertions(+), 13 deletions(-) --- a/drivers/power/supply/bq27xxx_battery.c +++ b/drivers/power/supply/bq27xxx_battery.c @@ -1801,7 +1801,7 @@ static void bq27xxx_battery_update_unloc di->last_update = jiffies; - if (poll_interval > 0) + if (!di->removed && poll_interval > 0) mod_delayed_work(system_wq, &di->work, poll_interval * HZ); } @@ -2132,22 +2132,18 @@ EXPORT_SYMBOL_GPL(bq27xxx_battery_setup) void bq27xxx_battery_teardown(struct bq27xxx_device_info *di) { - /* - * power_supply_unregister call bq27xxx_battery_get_property which - * call bq27xxx_battery_poll. - * Make sure that bq27xxx_battery_poll will not call - * schedule_delayed_work again after unregister (which cause OOPS). - */ - poll_interval = 0; - - cancel_delayed_work_sync(&di->work); - - power_supply_unregister(di->bat); - mutex_lock(&bq27xxx_list_lock); list_del(&di->list); mutex_unlock(&bq27xxx_list_lock); + /* Set removed to avoid bq27xxx_battery_update() re-queuing the work */ + mutex_lock(&di->lock); + di->removed = true; + mutex_unlock(&di->lock); + + cancel_delayed_work_sync(&di->work); + + power_supply_unregister(di->bat); mutex_destroy(&di->lock); } EXPORT_SYMBOL_GPL(bq27xxx_battery_teardown); --- a/include/linux/power/bq27xxx_battery.h +++ b/include/linux/power/bq27xxx_battery.h @@ -68,6 +68,7 @@ struct bq27xxx_device_info { struct bq27xxx_access_methods bus; struct bq27xxx_reg_cache cache; int charge_design_full; + bool removed; unsigned long last_update; struct delayed_work work; struct power_supply *bat;