kernel/git/stable/linux.git/drivers/base/dd.c, branch linux-5.18.y

driver core: fix potential deadlock in __driver_attach

2022-08-17T12:41:39+00:00

[ Upstream commit 70fe758352cafdee72a7b13bf9db065f9613ced8 ] In __driver_attach function, There are also AA deadlock problem, like the commit b232b02bf3c2 ("driver core: fix deadlock in __device_attach"). stack like commit b232b02bf3c2 ("driver core: fix deadlock in __device_attach"). list below: In __driver_attach function, The lock holding logic is as follows: ... __driver_attach if (driver_allows_async_probing(drv)) device_lock(dev) // get lock dev async_schedule_dev(__driver_attach_async_helper, dev); // func async_schedule_node async_schedule_node_domain(func) entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC); /* when fail or work limit, sync to execute func, but __driver_attach_async_helper will get lock dev as will, which will lead to A-A deadlock. */ if (!entry || atomic_read(&entry_count) > MAX_WORK) { func; else queue_work_node(node, system_unbound_wq, &entry->work) device_unlock(dev) As above show, when it is allowed to do async probes, because of out of memory or work limit, async work is not be allowed, to do sync execute instead. it will lead to A-A deadlock because of __driver_attach_async_helper getting lock dev. Reproduce: and it can be reproduce by make the condition (if (!entry || atomic_read(&entry_count) > MAX_WORK)) untenable, like below: [ 370.785650] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 370.787154] task:swapper/0 state:D stack: 0 pid: 1 ppid: 0 flags:0x00004000 [ 370.788865] Call Trace: [ 370.789374] [ 370.789841] __schedule+0x482/0x1050 [ 370.790613] schedule+0x92/0x1a0 [ 370.791290] schedule_preempt_disabled+0x2c/0x50 [ 370.792256] __mutex_lock.isra.0+0x757/0xec0 [ 370.793158] __mutex_lock_slowpath+0x1f/0x30 [ 370.794079] mutex_lock+0x50/0x60 [ 370.794795] __device_driver_lock+0x2f/0x70 [ 370.795677] ? driver_probe_device+0xd0/0xd0 [ 370.796576] __driver_attach_async_helper+0x1d/0xd0 [ 370.797318] ? driver_probe_device+0xd0/0xd0 [ 370.797957] async_schedule_node_domain+0xa5/0xc0 [ 370.798652] async_schedule_node+0x19/0x30 [ 370.799243] __driver_attach+0x246/0x290 [ 370.799828] ? driver_allows_async_probing+0xa0/0xa0 [ 370.800548] bus_for_each_dev+0x9d/0x130 [ 370.801132] driver_attach+0x22/0x30 [ 370.801666] bus_add_driver+0x290/0x340 [ 370.802246] driver_register+0x88/0x140 [ 370.802817] ? virtio_scsi_init+0x116/0x116 [ 370.803425] scsi_register_driver+0x1a/0x30 [ 370.804057] init_sd+0x184/0x226 [ 370.804533] do_one_initcall+0x71/0x3a0 [ 370.805107] kernel_init_freeable+0x39a/0x43a [ 370.805759] ? rest_init+0x150/0x150 [ 370.806283] kernel_init+0x26/0x230 [ 370.806799] ret_from_fork+0x1f/0x30 To fix the deadlock, move the async_schedule_dev outside device_lock, as we can see, in async_schedule_node_domain, the parameter of queue_work_node is system_unbound_wq, so it can accept concurrent operations. which will also not change the code logic, and will not lead to deadlock. Fixes: ef0ff68351be ("driver core: Probe devices asynchronously instead of the driver") Signed-off-by: Zhang Wensheng Link: https://lore.kernel.org/r/20220622074327.497102-1-zhangwensheng5@huawei.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

driver core: Fix wait_for_device_probe() & deferred_probe_timeout interaction

2022-06-14T16:45:00+00:00

[ Upstream commit 5ee76c256e928455212ab759c51d198fedbe7523 ] Mounting NFS rootfs was timing out when deferred_probe_timeout was non-zero [1]. This was because ip_auto_config() initcall times out waiting for the network interfaces to show up when deferred_probe_timeout was non-zero. While ip_auto_config() calls wait_for_device_probe() to make sure any currently running deferred probe work or asynchronous probe finishes, that wasn't sufficient to account for devices being deferred until deferred_probe_timeout. Commit 35a672363ab3 ("driver core: Ensure wait_for_device_probe() waits until the deferred_probe_timeout fires") tried to fix that by making sure wait_for_device_probe() waits for deferred_probe_timeout to expire before returning. However, if wait_for_device_probe() is called from the kernel_init() context: - Before deferred_probe_initcall() [2], it causes the boot process to hang due to a deadlock. - After deferred_probe_initcall() [3], it blocks kernel_init() from continuing till deferred_probe_timeout expires and beats the point of deferred_probe_timeout that's trying to wait for userspace to load modules. Neither of this is good. So revert the changes to wait_for_device_probe(). [1] - https://lore.kernel.org/lkml/TYAPR01MB45443DF63B9EF29054F7C41FD8C60@TYAPR01MB4544.jpnprd01.prod.outlook.com/ [2] - https://lore.kernel.org/lkml/YowHNo4sBjr9ijZr@dev-arch.thelio-3990X/ [3] - https://lore.kernel.org/lkml/Yo3WvGnNk3LvLb7R@linutronix.de/ Fixes: 35a672363ab3 ("driver core: Ensure wait_for_device_probe() waits until the deferred_probe_timeout fires") Cc: John Stultz Cc: "David S. Miller" Cc: Alexey Kuznetsov Cc: Hideaki YOSHIFUJI Cc: Jakub Kicinski Cc: Rob Herring Cc: Geert Uytterhoeven Cc: Yoshihiro Shimoda Cc: Robin Murphy Cc: Andy Shevchenko Cc: Sudeep Holla Cc: Andy Shevchenko Cc: Naresh Kamboju Cc: Basil Eljuse Cc: Ferry Toth Cc: Arnd Bergmann Cc: Anders Roxell Cc: linux-pm@vger.kernel.org Reported-by: Nathan Chancellor Reported-by: Sebastian Andrzej Siewior Tested-by: Geert Uytterhoeven Acked-by: John Stultz Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20220526034609.480766-2-saravanak@google.com Signed-off-by: Greg Kroah-Hartman Reviewed-by: Rafael J. Wysocki Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

driver core: fix deadlock in __device_attach

2022-06-14T16:44:52+00:00

[ Upstream commit b232b02bf3c205b13a26dcec08e53baddd8e59ed ] In __device_attach function, The lock holding logic is as follows: ... __device_attach device_lock(dev) // get lock dev async_schedule_dev(__device_attach_async_helper, dev); // func async_schedule_node async_schedule_node_domain(func) entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC); /* when fail or work limit, sync to execute func, but __device_attach_async_helper will get lock dev as well, which will lead to A-A deadlock. */ if (!entry || atomic_read(&entry_count) > MAX_WORK) { func; else queue_work_node(node, system_unbound_wq, &entry->work) device_unlock(dev) As shown above, when it is allowed to do async probes, because of out of memory or work limit, async work is not allowed, to do sync execute instead. it will lead to A-A deadlock because of __device_attach_async_helper getting lock dev. To fix the deadlock, move the async_schedule_dev outside device_lock, as we can see, in async_schedule_node_domain, the parameter of queue_work_node is system_unbound_wq, so it can accept concurrent operations. which will also not change the code logic, and will not lead to deadlock. Fixes: 765230b5f084 ("driver-core: add asynchronous probing support for drivers") Signed-off-by: Zhang Wensheng Link: https://lore.kernel.org/r/20220518074516.1225580-1-zhangwensheng5@huawei.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

net: mdio: don't defer probe forever if PHY IRQ provider is missing

2022-04-08T21:17:55+00:00

When a driver for an interrupt controller is missing, of_irq_get() returns -EPROBE_DEFER ad infinitum, causing fwnode_mdiobus_phy_device_register(), and ultimately, the entire of_mdiobus_register() call, to fail. In turn, any phy_connect() call towards a PHY on this MDIO bus will also fail. This is not what is expected to happen, because the PHY library falls back to poll mode when of_irq_get() returns a hard error code, and the MDIO bus, PHY and attached Ethernet controller work fine, albeit suboptimally, when the PHY library polls for link status. However, -EPROBE_DEFER has special handling given the assumption that at some point probe deferral will stop, and the driver for the supplier will kick in and create the IRQ domain. Reasons for which the interrupt controller may be missing: - It is not yet written. This may happen if a more recent DT blob (with an interrupt-parent for the PHY) is used to boot an old kernel where the driver didn't exist, and that kernel worked with the vintage-correct DT blob using poll mode. - It is compiled out. Behavior is the same as above. - It is compiled as a module. The kernel will wait for a number of seconds specified in the "deferred_probe_timeout" boot parameter for user space to load the required module. The current default is 0, which times out at the end of initcalls. It is possible that this might cause regressions unless users adjust this boot parameter. The proposed solution is to use the driver_deferred_probe_check_state() helper function provided by the driver core, which gives up after some -EPROBE_DEFER attempts, taking "deferred_probe_timeout" into consideration. The return code is changed from -EPROBE_DEFER into -ENODEV or -ETIMEDOUT, depending on whether the kernel is compiled with support for modules or not. Fixes: 66bdede495c7 ("of_mdio: Fix broken PHY IRQ in case of probe deferral") Suggested-by: Robin Murphy Signed-off-by: Vladimir Oltean Acked-by: Greg Kroah-Hartman Reviewed-by: Florian Fainelli Link: https://lore.kernel.org/r/20220407165538.4084809-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski

drivers/base/dd.c : Remove the initial value of the global variable

2022-03-18T13:31:31+00:00

The global variable driver_deferred_probe_enable has a default value of false and does not need to be initialized to false. Signed-off-by: lizhe Link: https://lore.kernel.org/r/20220309135418.31101-1-sensor1010@163.com Signed-off-by: Greg Kroah-Hartman

driver core: dd: fix return value of __setup handler

2022-03-18T13:27:51+00:00

When "driver_async_probe=nulltty" is used on the kernel boot command line, it causes an Unknown parameter message and the string is added to init's environment strings, polluting them. Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc6 driver_async_probe=nulltty", will be passed to user space. Run /sbin/init as init process with arguments: /sbin/init with environment: HOME=/ TERM=linux BOOT_IMAGE=/boot/bzImage-517rc6 driver_async_probe=nulltty Change the return value of the __setup function to 1 to indicate that the __setup option has been handled. Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Fixes: 1ea61b68d0f8 ("async: Add cmdline option to specify drivers to be async probed") Cc: Feng Tang Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Reported-by: Igor Zhbanov Reviewed-by: Feng Tang Signed-off-by: Randy Dunlap Link: https://lore.kernel.org/r/20220301041829.15137-1-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman

driver core: Refactor sysfs and drv/bus remove hooks

2022-03-18T13:27:26+00:00

There are 3 copies of the same device sysfs cleanup and drv/bus remove() hooks used for probe failure, testing re-probing, and device unbinding. Let's refactor the code to its own function. Signed-off-by: Rob Herring Link: https://lore.kernel.org/r/20220223225257.1681968-3-robh@kernel.org Signed-off-by: Greg Kroah-Hartman

driver core: Refactor multiple copies of device cleanup

2022-03-18T13:27:26+00:00

There are 3 copies of the same device cleanup code used for probe failure, testing re-probing, and device unbinding. Changes to this code often miss at least one of the copies of the code. See commits d0243bbd5dd3 ("drivers core: Free dma_range_map when driver probe failed") and d8f7a5484f21 ("driver core: Free DMA range map when device is released") for example. Let's refactor the code to its own function. Signed-off-by: Rob Herring Link: https://lore.kernel.org/r/20220223225257.1681968-2-robh@kernel.org Signed-off-by: Greg Kroah-Hartman

Merge 5.17-rc6 into driver-core-next

2022-02-28T06:45:41+00:00

We need the driver core fix in here as well for future changes. Signed-off-by: Greg Kroah-Hartman

driver core: Free DMA range map when device is released

2022-02-22T07:40:02+00:00

When unbinding/binding a driver with DMA mapped memory, the DMA map is not freed before the driver is reloaded. This leads to a memory leak when the DMA map is overwritten when reprobing the driver. This can be reproduced with a platform driver having a dma-range: dummy { ... #address-cells = <0x2>; #size-cells = <0x2>; ranges; dma-ranges = <...>; ... }; and then unbinding/binding it: ~# echo soc:dummy >/sys/bus/platform/drivers//unbind DMA map object 0xffffff800b0ae540 still being held by &pdev->dev ~# echo soc:dummy >/sys/bus/platform/drivers//bind ~# echo scan > /sys/kernel/debug/kmemleak ~# cat /sys/kernel/debug/kmemleak unreferenced object 0xffffff800b0ae540 (size 64): comm "sh", pid 833, jiffies 4295174550 (age 2535.352s) hex dump (first 32 bytes): 00 00 00 80 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 80 00 00 00 00 00 00 00 80 00 00 00 00 ................ backtrace: [] create_object.isra.0+0x108/0x344 [] kmemleak_alloc+0x8c/0xd0 [] __kmalloc+0x440/0x6f0 [] of_dma_get_range+0x124/0x220 [] of_dma_configure_id+0x40/0x2d0 [] platform_dma_configure+0x5c/0xa4 [] really_probe+0x8c/0x514 [] __driver_probe_device+0x9c/0x19c [] device_driver_attach+0x54/0xbc [] bind_store+0xc4/0x120 [] drv_attr_store+0x30/0x44 [] sysfs_kf_write+0x50/0x60 [] kernfs_fop_write_iter+0x124/0x1b4 [] new_sync_write+0xdc/0x160 [] vfs_write+0x23c/0x2a0 [] ksys_write+0x64/0xec To prevent this we should free the dma_range_map when the device is released. Fixes: e0d072782c73 ("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset") Cc: stable Suggested-by: Rob Herring Reviewed-by: Rob Herring Signed-off-by: Mårten Lindahl Link: https://lore.kernel.org/r/20220216094128.4025861-1-marten.lindahl@axis.com Signed-off-by: Greg Kroah-Hartman