kernel/linux.git/drivers/base, branch linux-4.20.y

driver core: Postpone DMA tear-down until after devres release

2019-03-10T06:10:09+00:00

commit 376991db4b6464e906d699ef07681e2ffa8ab08c upstream. When unbinding the (IOMMU-enabled) R-Car SATA device on Salvator-XS (R-Car H3 ES2.0), in preparation of rebinding against vfio-platform for device pass-through for virtualization: echo ee300000.sata > /sys/bus/platform/drivers/sata_rcar/unbind the kernel crashes with: Unable to handle kernel paging request at virtual address ffffffbf029ffffc Mem abort info: ESR = 0x96000006 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000006 CM = 0, WnR = 0 swapper pgtable: 4k pages, 39-bit VAs, pgdp = 000000007e8c586c [ffffffbf029ffffc] pgd=000000073bfc6003, pud=000000073bfc6003, pmd=0000000000000000 Internal error: Oops: 96000006 [#1] SMP Modules linked in: CPU: 0 PID: 1098 Comm: bash Not tainted 5.0.0-rc5-salvator-x-00452-g37596f884f4318ef #287 Hardware name: Renesas Salvator-X 2nd version board based on r8a7795 ES2.0+ (DT) pstate: 60400005 (nZCv daif +PAN -UAO) pc : __free_pages+0x8/0x58 lr : __dma_direct_free_pages+0x50/0x5c sp : ffffff801268baa0 x29: ffffff801268baa0 x28: 0000000000000000 x27: ffffffc6f9c60bf0 x26: ffffffc6f9c60bf0 x25: ffffffc6f9c60810 x24: 0000000000000000 x23: 00000000fffff000 x22: ffffff8012145000 x21: 0000000000000800 x20: ffffffbf029fffc8 x19: 0000000000000000 x18: ffffffc6f86c42c8 x17: 0000000000000000 x16: 0000000000000070 x15: 0000000000000003 x14: 0000000000000000 x13: ffffff801103d7f8 x12: 0000000000000028 x11: ffffff8011117604 x10: 0000000000009ad8 x9 : ffffff80110126d0 x8 : ffffffc6f7563000 x7 : 6b6b6b6b6b6b6b6b x6 : 0000000000000018 x5 : ffffff8011cf3cc8 x4 : 0000000000004000 x3 : 0000000000080000 x2 : 0000000000000001 x1 : 0000000000000000 x0 : ffffffbf029fffc8 Process bash (pid: 1098, stack limit = 0x00000000c38e3e32) Call trace: __free_pages+0x8/0x58 __dma_direct_free_pages+0x50/0x5c arch_dma_free+0x1c/0x98 dma_direct_free+0x14/0x24 dma_free_attrs+0x9c/0xdc dmam_release+0x18/0x20 release_nodes+0x25c/0x28c devres_release_all+0x48/0x4c device_release_driver_internal+0x184/0x1f0 device_release_driver+0x14/0x1c unbind_store+0x70/0xb8 drv_attr_store+0x24/0x34 sysfs_kf_write+0x4c/0x64 kernfs_fop_write+0x154/0x1c4 __vfs_write+0x34/0x164 vfs_write+0xb4/0x16c ksys_write+0x5c/0xbc __arm64_sys_write+0x14/0x1c el0_svc_common+0x98/0x114 el0_svc_handler+0x1c/0x24 el0_svc+0x8/0xc Code: d51b4234 17fffffa a9bf7bfd 910003fd (b9403404) ---[ end trace 8c564cdd3a1a840f ]--- While I've bisected this to commit e8e683ae9a736407 ("iommu/of: Fix probe-deferral"), and reverting that commit on post-v5.0-rc4 kernels does fix the problem, this turned out to be a red herring. On arm64, arch_teardown_dma_ops() resets dev->dma_ops to NULL. Hence if a driver has used a managed DMA allocation API, the allocated DMA memory will be freed using the direct DMA ops, while it may have been allocated using a custom DMA ops (iommu_dma_ops in this case). Fix this by reversing the order of the calls to devres_release_all() and arch_teardown_dma_ops(). Signed-off-by: Geert Uytterhoeven Acked-by: Christoph Hellwig Reviewed-by: Rafael J. Wysocki Cc: stable Reviewed-by: Robin Murphy Signed-off-by: Greg Kroah-Hartman

cacheinfo: Keep the old value if of_property_read_u32 fails

2019-02-12T19:02:38+00:00

commit 3a34c986324c07dde32903f7bb262e6138e77c2a upstream. Commit 448a5a552f336bd7b847b1951 ("drivers: base: cacheinfo: use OF property_read_u32 instead of get_property,read_number") makes cache size and number_of_sets be 0 if DT doesn't provide there values. I think this is unreasonable so make them keep the old values, which is the same as old kernels. Fixes: 448a5a552f33 ("drivers: base: cacheinfo: use OF property_read_u32 instead of get_property,read_number") Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen Reviewed-by: Sudeep Holla Signed-off-by: Greg Kroah-Hartman

kobject: return error code if writing /sys/.../uevent fails

2019-02-12T19:02:15+00:00

[ Upstream commit df44b479654f62b478c18ee4d8bc4e9f897a9844 ] Propagate error code back to userspace if writing the /sys/.../uevent file fails. Before, the write operation always returned with success, even if we failed to recognize the input string or if we failed to generate the uevent itself. With the error codes properly propagated back to userspace, we are able to react in userspace accordingly by not assuming and awaiting a uevent that is not delivered. Signed-off-by: Peter Rajnoha Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

driver core: Move async_synchronize_full call

2019-02-12T19:02:15+00:00

[ Upstream commit c37d721c68ad88925ba0e72f6e14acb829a8c6bb ] Move the async_synchronize_full call out of __device_release_driver and into driver_detach. The idea behind this is that the async_synchronize_full call will only guarantee that any existing async operations are flushed. This doesn't do anything to guarantee that a hotplug event that may occur while we are doing the release of the driver will not be asynchronously scheduled. By moving this into the driver_detach path we can avoid potential deadlocks as we aren't holding the device lock at this point and we should not have the driver we want to flush loaded so the flush will take care of any asynchronous events the driver we are detaching might have scheduled. Fixes: 765230b5f084 ("driver-core: add asynchronous probing support for drivers") Reviewed-by: Bart Van Assche Reviewed-by: Dan Williams Signed-off-by: Alexander Duyck Reviewed-by: Luis Chamberlain Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

sysfs: Disable lockdep for driver bind/unbind files

2019-01-26T08:20:49+00:00

[ Upstream commit 4f4b374332ec0ae9c738ff8ec9bed5cd97ff9adc ] This is the much more correct fix for my earlier attempt at: https://lkml.org/lkml/2018/12/10/118 Short recap: - There's not actually a locking issue, it's just lockdep being a bit too eager to complain about a possible deadlock. - Contrary to what I claimed the real problem is recursion on kn->count. Greg pointed me at sysfs_break_active_protection(), used by the scsi subsystem to allow a sysfs file to unbind itself. That would be a real deadlock, which isn't what's happening here. Also, breaking the active protection means we'd need to manually handle all the lifetime fun. - With Rafael we discussed the task_work approach, which kinda works, but has two downsides: It's a functional change for a lockdep annotation issue, and it won't work for the bind file (which needs to get the errno from the driver load function back to userspace). - Greg also asked why this never showed up: To hit this you need to unregister a 2nd driver from the unload code of your first driver. I guess only gpus do that. The bug has always been there, but only with a recent patch series did we add more locks so that lockdep built a chain from unbinding the snd-hda driver to the acpi_video_unregister call. Full lockdep splat: [12301.898799] ============================================ [12301.898805] WARNING: possible recursive locking detected [12301.898811] 4.20.0-rc7+ #84 Not tainted [12301.898815] -------------------------------------------- [12301.898821] bash/5297 is trying to acquire lock: [12301.898826] 00000000f61c6093 (kn->count#39){++++}, at: kernfs_remove_by_name_ns+0x3b/0x80 [12301.898841] but task is already holding lock: [12301.898847] 000000005f634021 (kn->count#39){++++}, at: kernfs_fop_write+0xdc/0x190 [12301.898856] other info that might help us debug this: [12301.898862] Possible unsafe locking scenario: [12301.898867] CPU0 [12301.898870] ---- [12301.898874] lock(kn->count#39); [12301.898879] lock(kn->count#39); [12301.898883] *** DEADLOCK *** [12301.898891] May be due to missing lock nesting notation [12301.898899] 5 locks held by bash/5297: [12301.898903] #0: 00000000cd800e54 (sb_writers#4){.+.+}, at: vfs_write+0x17f/0x1b0 [12301.898915] #1: 000000000465e7c2 (&of->mutex){+.+.}, at: kernfs_fop_write+0xd3/0x190 [12301.898925] #2: 000000005f634021 (kn->count#39){++++}, at: kernfs_fop_write+0xdc/0x190 [12301.898936] #3: 00000000414ef7ac (&dev->mutex){....}, at: device_release_driver_internal+0x34/0x240 [12301.898950] #4: 000000003218fbdf (register_count_mutex){+.+.}, at: acpi_video_unregister+0xe/0x40 [12301.898960] stack backtrace: [12301.898968] CPU: 1 PID: 5297 Comm: bash Not tainted 4.20.0-rc7+ #84 [12301.898974] Hardware name: Hewlett-Packard HP EliteBook 8460p/161C, BIOS 68SCF Ver. F.01 03/11/2011 [12301.898982] Call Trace: [12301.898989] dump_stack+0x67/0x9b [12301.898997] __lock_acquire+0x6ad/0x1410 [12301.899003] ? kernfs_remove_by_name_ns+0x3b/0x80 [12301.899010] ? find_held_lock+0x2d/0x90 [12301.899017] ? mutex_spin_on_owner+0xe4/0x150 [12301.899023] ? find_held_lock+0x2d/0x90 [12301.899030] ? lock_acquire+0x90/0x180 [12301.899036] lock_acquire+0x90/0x180 [12301.899042] ? kernfs_remove_by_name_ns+0x3b/0x80 [12301.899049] __kernfs_remove+0x296/0x310 [12301.899055] ? kernfs_remove_by_name_ns+0x3b/0x80 [12301.899060] ? kernfs_name_hash+0xd/0x80 [12301.899066] ? kernfs_find_ns+0x6c/0x100 [12301.899073] kernfs_remove_by_name_ns+0x3b/0x80 [12301.899080] bus_remove_driver+0x92/0xa0 [12301.899085] acpi_video_unregister+0x24/0x40 [12301.899127] i915_driver_unload+0x42/0x130 [i915] [12301.899160] i915_pci_remove+0x19/0x30 [i915] [12301.899169] pci_device_remove+0x36/0xb0 [12301.899176] device_release_driver_internal+0x185/0x240 [12301.899183] unbind_store+0xaf/0x180 [12301.899189] kernfs_fop_write+0x104/0x190 [12301.899195] __vfs_write+0x31/0x180 [12301.899203] ? rcu_read_lock_sched_held+0x6f/0x80 [12301.899209] ? rcu_sync_lockdep_assert+0x29/0x50 [12301.899216] ? __sb_start_write+0x13c/0x1a0 [12301.899221] ? vfs_write+0x17f/0x1b0 [12301.899227] vfs_write+0xb9/0x1b0 [12301.899233] ksys_write+0x50/0xc0 [12301.899239] do_syscall_64+0x4b/0x180 [12301.899247] entry_SYSCALL_64_after_hwframe+0x49/0xbe [12301.899253] RIP: 0033:0x7f452ac7f7a4 [12301.899259] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 80 00 00 00 00 8b 05 aa f0 2c 00 48 63 ff 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 55 53 48 89 d5 48 89 f3 48 83 [12301.899273] RSP: 002b:00007ffceafa6918 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [12301.899282] RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007f452ac7f7a4 [12301.899288] RDX: 000000000000000d RSI: 00005612a1abf7c0 RDI: 0000000000000001 [12301.899295] RBP: 00005612a1abf7c0 R08: 000000000000000a R09: 00005612a1c46730 [12301.899301] R10: 000000000000000a R11: 0000000000000246 R12: 000000000000000d [12301.899308] R13: 0000000000000001 R14: 00007f452af4a740 R15: 000000000000000d Looking around I've noticed that usb and i2c already handle similar recursion problems, where a sysfs file can unbind the same type of sysfs somewhere else in the hierarchy. Relevant commits are: commit 356c05d58af05d582e634b54b40050c73609617b Author: Alan Stern Date: Mon May 14 13:30:03 2012 -0400 sysfs: get rid of some lockdep false positives commit e9b526fe704812364bca07edd15eadeba163ebfb Author: Alexander Sverdlin Date: Fri May 17 14:56:35 2013 +0200 i2c: suppress lockdep warning on delete_device Implement the same trick for driver bind/unbind. v2: Put the macro into bus.c (Greg). Reviewed-by: Rafael J. Wysocki Cc: Ramalingam C Cc: Arend van Spriel Cc: Andy Shevchenko Cc: Geert Uytterhoeven Cc: Bartosz Golaszewski Cc: Heikki Krogerus Cc: Vivek Gautam Cc: Joe Perches Signed-off-by: Daniel Vetter Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

driver core: Add missing dev->bus->need_parent_lock checks

2019-01-13T08:24:05+00:00

commit e121a833745b4708b660e3fe6776129c2956b041 upstream. __device_release_driver() has to check dev->bus->need_parent_lock before dropping the parent lock and acquiring it again as it may attempt to drop a lock that hasn't been acquired or lock a device that shouldn't be locked and create a lock imbalance. Fixes: 8c97a46af04b (driver core: hold dev's parent lock when needed) Signed-off-by: Rafael J. Wysocki Cc: stable Reviewed-by: Daniel Vetter Signed-off-by: Greg Kroah-Hartman

platform-msi: Free descriptors in platform_msi_domain_free()

2019-01-09T16:45:55+00:00

commit 81b1e6e6a8590a19257e37a1633bec098d499c57 upstream. Since the addition of platform MSI support, there were two helpers supposed to allocate/free IRQs for a device: platform_msi_domain_alloc_irqs() platform_msi_domain_free_irqs() In these helpers, IRQ descriptors are allocated in the "alloc" routine while they are freed in the "free" one. Later, two other helpers have been added to handle IRQ domains on top of MSI domains: platform_msi_domain_alloc() platform_msi_domain_free() Seen from the outside, the logic is pretty close with the former helpers and people used it with the same logic as before: a platform_msi_domain_alloc() call should be balanced with a platform_msi_domain_free() call. While this is probably what was intended to do, the platform_msi_domain_free() does not remove/free the IRQ descriptor(s) created/inserted in platform_msi_domain_alloc(). One effect of such situation is that removing a module that requested an IRQ will let one orphaned IRQ descriptor (with an allocated MSI entry) in the device descriptors list. Next time the module will be inserted back, one will observe that the allocation will happen twice in the MSI domain, one time for the remaining descriptor, one time for the new one. It also has the side effect to quickly overshoot the maximum number of allocated MSI and then prevent any module requesting an interrupt in the same domain to be inserted anymore. This situation has been met with loops of insertion/removal of the mvpp2.ko module (requesting 15 MSIs each time). Fixes: 552c494a7666 ("platform-msi: Allow creation of a MSI-based stacked irq domain") Cc: stable@vger.kernel.org Signed-off-by: Miquel Raynal Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman

devres: Align data[] to ARCH_KMALLOC_MINALIGN

2018-11-11T19:40:04+00:00

Initially we bumped into problem with 32-bit aligned atomic64_t on ARC, see [1]. And then during quite lengthly discussion Peter Z. mentioned ARCH_KMALLOC_MINALIGN which IMHO makes perfect sense. If allocation is done by plain kmalloc() obtained buffer will be ARCH_KMALLOC_MINALIGN aligned and then why buffer obtained via devm_kmalloc() should have any other alignment? This way we at least get the same behavior for both types of allocation. [1] http://lists.infradead.org/pipermail/linux-snps-arc/2018-July/004009.html [2] http://lists.infradead.org/pipermail/linux-snps-arc/2018-July/004036.html Signed-off-by: Alexey Brodkin Cc: Greg Kroah-Hartman Cc: Geert Uytterhoeven Cc: David Laight Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vineet Gupta Cc: Will Deacon Cc: Greg KH Cc: # 4.8+ Signed-off-by: Greg Kroah-Hartman

mm/memory_hotplug: fix online/offline_pages called w.o. mem_hotplug_lock

2018-10-31T15:54:17+00:00

There seem to be some problems as result of 30467e0b3be ("mm, hotplug: fix concurrent memory hot-add deadlock"), which tried to fix a possible lock inversion reported and discussed in [1] due to the two locks a) device_lock() b) mem_hotplug_lock While add_memory() first takes b), followed by a) during bus_probe_device(), onlining of memory from user space first took a), followed by b), exposing a possible deadlock. In [1], and it was decided to not make use of device_hotplug_lock, but rather to enforce a locking order. The problems I spotted related to this: 1. Memory block device attributes: While .state first calls mem_hotplug_begin() and the calls device_online() - which takes device_lock() - .online does no longer call mem_hotplug_begin(), so effectively calls online_pages() without mem_hotplug_lock. 2. device_online() should be called under device_hotplug_lock, however onlining memory during add_memory() does not take care of that. In addition, I think there is also something wrong about the locking in 3. arch/powerpc/platforms/powernv/memtrace.c calls offline_pages() without locks. This was introduced after 30467e0b3be. And skimming over the code, I assume it could need some more care in regards to locking (e.g. device_online() called without device_hotplug_lock. This will be addressed in the following patches. Now that we hold the device_hotplug_lock when - adding memory (e.g. via add_memory()/add_memory_resource()) - removing memory (e.g. via remove_memory()) - device_online()/device_offline() We can move mem_hotplug_lock usage back into online_pages()/offline_pages(). Why is mem_hotplug_lock still needed? Essentially to make get_online_mems()/put_online_mems() be very fast (relying on device_hotplug_lock would be very slow), and to serialize against addition of memory that does not create memory block devices (hmm). [1] http://driverdev.linuxdriverproject.org/pipermail/ driverdev-devel/ 2015-February/065324.html This patch is partly based on a patch by Vitaly Kuznetsov. Link: http://lkml.kernel.org/r/20180925091457.28651-4-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Pavel Tatashin Reviewed-by: Rashmica Gupta Reviewed-by: Oscar Salvador Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: "Rafael J. Wysocki" Cc: Len Brown Cc: Greg Kroah-Hartman Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Rashmica Gupta Cc: Michael Neuling Cc: Balbir Singh Cc: Kate Stewart Cc: Thomas Gleixner Cc: Philippe Ombredanne Cc: Pavel Tatashin Cc: Vlastimil Babka Cc: Dan Williams Cc: Oscar Salvador Cc: YASUAKI ISHIMATSU Cc: Mathieu Malaterre Cc: John Allen Cc: Jonathan Corbet Cc: Joonsoo Kim Cc: Nathan Fontenot Cc: Rafael J. Wysocki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: make add_memory() take the device_hotplug_lock

2018-10-31T15:54:17+00:00

add_memory() currently does not take the device_hotplug_lock, however is aleady called under the lock from arch/powerpc/platforms/pseries/hotplug-memory.c drivers/acpi/acpi_memhotplug.c to synchronize against CPU hot-remove and similar. In general, we should hold the device_hotplug_lock when adding memory to synchronize against online/offline request (e.g. from user space) - which already resulted in lock inversions due to device_lock() and mem_hotplug_lock - see 30467e0b3be ("mm, hotplug: fix concurrent memory hot-add deadlock"). add_memory()/add_memory_resource() will create memory block devices, so this really feels like the right thing to do. Holding the device_hotplug_lock makes sure that a memory block device can really only be accessed (e.g. via .online/.state) from user space, once the memory has been fully added to the system. The lock is not held yet in drivers/xen/balloon.c arch/powerpc/platforms/powernv/memtrace.c drivers/s390/char/sclp_cmd.c drivers/hv/hv_balloon.c So, let's either use the locked variants or take the lock. Don't export add_memory_resource(), as it once was exported to be used by XEN, which is never built as a module. If somebody requires it, we also have to export a locked variant (as device_hotplug_lock is never exported). Link: http://lkml.kernel.org/r/20180925091457.28651-3-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Pavel Tatashin Reviewed-by: Rafael J. Wysocki Reviewed-by: Rashmica Gupta Reviewed-by: Oscar Salvador Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: "Rafael J. Wysocki" Cc: Len Brown Cc: Greg Kroah-Hartman Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Nathan Fontenot Cc: John Allen Cc: Michal Hocko Cc: Dan Williams Cc: Joonsoo Kim Cc: Vlastimil Babka Cc: Mathieu Malaterre Cc: Pavel Tatashin Cc: YASUAKI ISHIMATSU Cc: Balbir Singh Cc: Haiyang Zhang Cc: Heiko Carstens Cc: Jonathan Corbet Cc: Kate Stewart Cc: "K. Y. Srinivasan" Cc: Martin Schwidefsky Cc: Michael Neuling Cc: Philippe Ombredanne Cc: Stephen Hemminger Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds