pm24.git/block, branch v4.12

block: provide bio_uninit() free freeing integrity/task associations

2017-06-28T21:30:13Z

Wen reports significant memory leaks with DIF and O_DIRECT: "With nvme devive + T10 enabled, On a system it has 256GB and started logging /proc/meminfo & /proc/slabinfo for every minute and in an hour it increased by 15968128 kB or ~15+GB.. Approximately 256 MB / minute leaking. /proc/meminfo | grep SUnreclaim... SUnreclaim: 6752128 kB SUnreclaim: 6874880 kB SUnreclaim: 7238080 kB .... SUnreclaim: 22307264 kB SUnreclaim: 22485888 kB SUnreclaim: 22720256 kB When testcases with T10 enabled call into __blkdev_direct_IO_simple, code doesn't free memory allocated by bio_integrity_alloc. The patch fixes the issue. HTX has been run with +60 hours without failure." Since __blkdev_direct_IO_simple() allocates the bio on the stack, it doesn't go through the regular bio free. This means that any ancillary data allocated with the bio through the stack is not freed. Hence, we can leak the integrity data associated with the bio, if the device is using DIF/DIX. Fix this by providing a bio_uninit() and export it, so that we can use it to free this data. Note that this is a minimal fix for this issue. Any current user of bio's that are allocated outside of bio_alloc_bioset() suffers from this issue, most notably some drivers. We will fix those in a more comprehensive patch for 4.13. This also means that the commit marked as being fixed by this isn't the real culprit, it's just the most obvious one out there. Fixes: 542ff7bf18c6 ("block: new direct I/O implementation") Reported-by: Wen Xiong Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

blk-mq: fix performance regression with shared tags

2017-06-21T16:17:49Z

If we have shared tags enabled, then every IO completion will trigger a full loop of every queue belonging to a tag set, and every hardware queue for each of those queues, even if nothing needs to be done. This causes a massive performance regression if you have a lot of shared devices. Instead of doing this huge full scan on every IO, add an atomic counter to the main queue that tracks how many hardware queues have been marked as needing a restart. With that, we can avoid looking for restartable queues, if we don't have to. Max reports that this restores performance. Before this patch, 4K IOPS was limited to 22-23K IOPS. With the patch, we are running at 950-970K IOPS. Fixes: 6d8c6c0f97ad ("blk-mq: Restart a single queue if tag sets are shared") Reported-by: Max Gurtovoy Tested-by: Max Gurtovoy Reviewed-by: Bart Van Assche Tested-by: Bart Van Assche Signed-off-by: Jens Axboe

block: Fix a blk_exit_rl() regression

2017-06-14T19:27:50Z

Avoid that the following complaint is reported: BUG: sleeping function called from invalid context at kernel/workqueue.c:2790 in_atomic(): 1, irqs_disabled(): 0, pid: 41, name: rcuop/3 1 lock held by rcuop/3/41: #0: (rcu_callback){......}, at: [] rcu_nocb_kthread+0x282/0x500 Call Trace: dump_stack+0x86/0xcf ___might_sleep+0x174/0x260 __might_sleep+0x4a/0x80 flush_work+0x7e/0x2e0 __cancel_work_timer+0x143/0x1c0 cancel_work_sync+0x10/0x20 blk_throtl_exit+0x25/0x60 blkcg_exit_queue+0x35/0x40 blk_release_queue+0x42/0x130 kobject_put+0xa9/0x190 This happens since we invoke callbacks that need to block from the queue release handler. Fix this by pushing the final release to a workqueue. Reported-by: Ross Zwisler Fixes: commit b425e5049258 ("block: Avoid that blk_exit_rl() triggers a use-after-free") Signed-off-by: Bart Van Assche Tested-by: Ross Zwisler Updated changelog Signed-off-by: Jens Axboe

block, bfq: access and cache blkg data only when safe

2017-06-08T15:51:10Z

In blk-cgroup, operations on blkg objects are protected with the request_queue lock. This is no more the lock that protects I/O-scheduler operations in blk-mq. In fact, the latter are now protected with a finer-grained per-scheduler-instance lock. As a consequence, although blkg lookups are also rcu-protected, blk-mq I/O schedulers may see inconsistent data when they access blkg and blkg-related objects. BFQ does access these objects, and does incur this problem, in the following case. The blkg_lookup performed in bfq_get_queue, being protected (only) through rcu, may happen to return the address of a copy of the original blkg. If this is the case, then the blkg_get performed in bfq_get_queue, to pin down the blkg, is useless: it does not prevent blk-cgroup code from destroying both the original blkg and all objects directly or indirectly referred by the copy of the blkg. BFQ accesses these objects, which typically causes a crash for NULL-pointer dereference of memory-protection violation. Some additional protection mechanism should be added to blk-cgroup to address this issue. In the meantime, this commit provides a quick temporary fix for BFQ: cache (when safe) blkg data that might disappear right after a blkg_lookup. In particular, this commit exploits the following facts to achieve its goal without introducing further locks. Destroy operations on a blkg invoke, as a first step, hooks of the scheduler associated with the blkg. And these hooks are executed with bfqd->lock held for BFQ. As a consequence, for any blkg associated with the request queue an instance of BFQ is attached to, we are guaranteed that such a blkg is not destroyed, and that all the pointers it contains are consistent, while that instance is holding its bfqd->lock. A blkg_lookup performed with bfqd->lock held then returns a fully consistent blkg, which remains consistent until this lock is held. In more detail, this holds even if the returned blkg is a copy of the original one. Finally, also the object describing a group inside BFQ needs to be protected from destruction on the blkg_free of the original blkg (which invokes bfq_pd_free). This commit adds private refcounting for this object, to let it disappear only after no bfq_queue refers to it any longer. This commit also removes or updates some stale comments on locking issues related to blk-cgroup operations. Reported-by: Tomas Konir Reported-by: Lee Tibbert Reported-by: Marco Piazza Signed-off-by: Paolo Valente Tested-by: Tomas Konir Tested-by: Lee Tibbert Tested-by: Marco Piazza Signed-off-by: Jens Axboe

blk-throttle: set default latency baseline for harddisk

2017-06-07T15:09:32Z

hard disk IO latency varies a lot depending on spindle move. The latency range could be from several microseconds to several milliseconds. It's pretty hard to get the baseline latency used by io.low. We will use a different stragety here. The idea is only using IO with spindle move to determine if cgroup IO is in good state. For HD, if io latency is small (< 1ms), we ignore the IO. Such IO is likely from sequential IO, and is helpless to help determine if a cgroup's IO is impacted by other cgroups. With this, we only account IO with big latency. Then we can choose a hardcoded baseline latency for HD (4ms, which is typical IO latency with seek). With all these settings, the io.low latency works for both HD and SSD. Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe

blk-throttle: fix NULL pointer dereference in throtl_schedule_pending_timer

2017-06-07T14:11:24Z

I have encountered a NULL pointer dereference in throtl_schedule_pending_timer: [ 413.735396] BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 [ 413.735535] IP: [] throtl_schedule_pending_timer+0x3f/0x210 [ 413.735643] PGD 22c8cf067 PUD 22cb34067 PMD 0 [ 413.735713] Oops: 0000 [#1] SMP ...... This is caused by the following case: blk_throtl_bio throtl_schedule_next_dispatch <= sq is top level one without parent throtl_schedule_pending_timer sq_to_tg(sq)->td->throtl_slice <= sq_to_tg(sq) returns NULL Fix it by using sq_to_td instead of sq_to_tg(sq)->td, which will always return a valid td. Fixes: 297e3d854784 ("blk-throttle: make throtl_slice tunable") Signed-off-by: Joseph Qi Reviewed-by: Shaohua Li Signed-off-by: Jens Axboe

blk-mq: fix direct issue

2017-06-06T16:00:35Z

If queue is stopped, we shouldn't dispatch request into driver and hardware, unfortunately the check is removed in bd166ef183c2(blk-mq-sched: add framework for MQ capable IO schedulers). This patch fixes the issue by moving the check back into __blk_mq_try_issue_directly(). This patch fixes request use-after-free[1][2] during canceling requets of NVMe in nvme_dev_disable(), which can be triggered easily during NVMe reset & remove test. [1] oops kernel log when CONFIG_BLK_DEV_INTEGRITY is on [ 103.412969] BUG: unable to handle kernel NULL pointer dereference at 000000000000000a [ 103.412980] IP: bio_integrity_advance+0x48/0xf0 [ 103.412981] PGD 275a88067 [ 103.412981] P4D 275a88067 [ 103.412982] PUD 276c43067 [ 103.412983] PMD 0 [ 103.412984] [ 103.412986] Oops: 0000 [#1] SMP [ 103.412989] Modules linked in: vfat fat intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel crypto_simd cryptd ipmi_ssif iTCO_wdt iTCO_vendor_support mxm_wmi glue_helper dcdbas ipmi_si mei_me pcspkr mei sg ipmi_devintf lpc_ich ipmi_msghandler shpchp acpi_power_meter wmi nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c sd_mod mgag200 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm crc32c_intel nvme ahci nvme_core libahci libata tg3 i2c_core megaraid_sas ptp pps_core dm_mirror dm_region_hash dm_log dm_mod [ 103.413035] CPU: 0 PID: 102 Comm: kworker/0:2 Not tainted 4.11.0+ #1 [ 103.413036] Hardware name: Dell Inc. PowerEdge R730xd/072T6D, BIOS 2.2.5 09/06/2016 [ 103.413041] Workqueue: events nvme_remove_dead_ctrl_work [nvme] [ 103.413043] task: ffff9cc8775c8000 task.stack: ffffc033c252c000 [ 103.413045] RIP: 0010:bio_integrity_advance+0x48/0xf0 [ 103.413046] RSP: 0018:ffffc033c252fc10 EFLAGS: 00010202 [ 103.413048] RAX: 0000000000000000 RBX: ffff9cc8720a8cc0 RCX: ffff9cca72958240 [ 103.413049] RDX: ffff9cca72958000 RSI: 0000000000000008 RDI: ffff9cc872537f00 [ 103.413049] RBP: ffffc033c252fc28 R08: 0000000000000000 R09: ffffffffb963a0d5 [ 103.413050] R10: 000000000000063e R11: 0000000000000000 R12: ffff9cc8720a8d18 [ 103.413051] R13: 0000000000001000 R14: ffff9cc872682e00 R15: 00000000fffffffb [ 103.413053] FS: 0000000000000000(0000) GS:ffff9cc877c00000(0000) knlGS:0000000000000000 [ 103.413054] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 103.413055] CR2: 000000000000000a CR3: 0000000276c41000 CR4: 00000000001406f0 [ 103.413056] Call Trace: [ 103.413063] bio_advance+0x2a/0xe0 [ 103.413067] blk_update_request+0x76/0x330 [ 103.413072] blk_mq_end_request+0x1a/0x70 [ 103.413074] blk_mq_dispatch_rq_list+0x370/0x410 [ 103.413076] ? blk_mq_flush_busy_ctxs+0x94/0xe0 [ 103.413080] blk_mq_sched_dispatch_requests+0x173/0x1a0 [ 103.413083] __blk_mq_run_hw_queue+0x8e/0xa0 [ 103.413085] __blk_mq_delay_run_hw_queue+0x9d/0xa0 [ 103.413088] blk_mq_start_hw_queue+0x17/0x20 [ 103.413090] blk_mq_start_hw_queues+0x32/0x50 [ 103.413095] nvme_kill_queues+0x54/0x80 [nvme_core] [ 103.413097] nvme_remove_dead_ctrl_work+0x1f/0x40 [nvme] [ 103.413103] process_one_work+0x149/0x360 [ 103.413105] worker_thread+0x4d/0x3c0 [ 103.413109] kthread+0x109/0x140 [ 103.413111] ? rescuer_thread+0x380/0x380 [ 103.413113] ? kthread_park+0x60/0x60 [ 103.413120] ret_from_fork+0x2c/0x40 [ 103.413121] Code: 08 4c 8b 63 50 48 8b 80 80 00 00 00 48 8b 90 d0 03 00 00 31 c0 48 83 ba 40 02 00 00 00 48 8d 8a 40 02 00 00 48 0f 45 c1 c1 ee 09 <0f> b6 48 0a 0f b6 40 09 41 89 f5 83 e9 09 41 d3 ed 44 0f af e8 [ 103.413145] RIP: bio_integrity_advance+0x48/0xf0 RSP: ffffc033c252fc10 [ 103.413146] CR2: 000000000000000a [ 103.413157] ---[ end trace cd6875d16eb5a11e ]--- [ 103.455368] Kernel panic - not syncing: Fatal exception [ 103.459826] Kernel Offset: 0x37600000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 103.850916] ---[ end Kernel panic - not syncing: Fatal exception [ 103.857637] sched: Unexpected reschedule of offline CPU#1! [ 103.863762] ------------[ cut here ]------------ [2] kernel hang in blk_mq_freeze_queue_wait() when CONFIG_BLK_DEV_INTEGRITY is off [ 247.129825] INFO: task nvme-test:1772 blocked for more than 120 seconds. [ 247.137311] Not tainted 4.12.0-rc2.upstream+ #4 [ 247.142954] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 247.151704] Call Trace: [ 247.154445] __schedule+0x28a/0x880 [ 247.158341] schedule+0x36/0x80 [ 247.161850] blk_mq_freeze_queue_wait+0x4b/0xb0 [ 247.166913] ? remove_wait_queue+0x60/0x60 [ 247.171485] blk_freeze_queue+0x1a/0x20 [ 247.175770] blk_cleanup_queue+0x7f/0x140 [ 247.180252] nvme_ns_remove+0xa3/0xb0 [nvme_core] [ 247.185503] nvme_remove_namespaces+0x32/0x50 [nvme_core] [ 247.191532] nvme_uninit_ctrl+0x2d/0xa0 [nvme_core] [ 247.196977] nvme_remove+0x70/0x110 [nvme] [ 247.201545] pci_device_remove+0x39/0xc0 [ 247.205927] device_release_driver_internal+0x141/0x200 [ 247.211761] device_release_driver+0x12/0x20 [ 247.216531] pci_stop_bus_device+0x8c/0xa0 [ 247.221104] pci_stop_and_remove_bus_device_locked+0x1a/0x30 [ 247.227420] remove_store+0x7c/0x90 [ 247.231320] dev_attr_store+0x18/0x30 [ 247.235409] sysfs_kf_write+0x3a/0x50 [ 247.239497] kernfs_fop_write+0xff/0x180 [ 247.243867] __vfs_write+0x37/0x160 [ 247.247757] ? selinux_file_permission+0xe5/0x120 [ 247.253011] ? security_file_permission+0x3b/0xc0 [ 247.258260] vfs_write+0xb2/0x1b0 [ 247.261964] ? syscall_trace_enter+0x1d0/0x2b0 [ 247.266924] SyS_write+0x55/0xc0 [ 247.270540] do_syscall_64+0x67/0x150 [ 247.274636] entry_SYSCALL64_slow_path+0x25/0x25 [ 247.279794] RIP: 0033:0x7f5c96740840 [ 247.283785] RSP: 002b:00007ffd00e87ee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 247.292238] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f5c96740840 [ 247.300194] RDX: 0000000000000002 RSI: 00007f5c97060000 RDI: 0000000000000001 [ 247.308159] RBP: 00007f5c97060000 R08: 000000000000000a R09: 00007f5c97059740 [ 247.316123] R10: 0000000000000001 R11: 0000000000000246 R12: 00007f5c96a14400 [ 247.324087] R13: 0000000000000002 R14: 0000000000000001 R15: 0000000000000000 [ 370.016340] INFO: task nvme-test:1772 blocked for more than 120 seconds. Fixes: 12d70958a2e8(blk-mq: don't fail allocating driver tag for stopped hw queue) Cc: stable@vger.kernel.org Signed-off-by: Ming Lei Reviewed-by: Bart Van Assche Signed-off-by: Jens Axboe

blk-mq: pass correct hctx to blk_mq_try_issue_directly

2017-06-06T16:00:33Z

When direct issue is done on request picked up from plug list, the hctx need to be updated with the actual hw queue, otherwise wrong hctx is used and may hurt performance, especially when wrong SRCU readlock is acquired/released Reported-by: Bart Van Assche Signed-off-by: Ming Lei Signed-off-by: Jens Axboe

bio-integrity: Do not allocate integrity context for bio w/o data

2017-06-03T13:36:27Z

If bio has no data, such as ones from blkdev_issue_flush(), then we have nothing to protect. This patch prevent bugon like follows: kfree_debugcheck: out of range ptr ac1fa1d106742a5ah kernel BUG at mm/slab.c:2773! invalid opcode: 0000 [#1] SMP Modules linked in: bcache CPU: 0 PID: 4428 Comm: xfs_io Tainted: G W 4.11.0-rc4-ext4-00041-g2ef0043-dirty #43 Hardware name: Virtuozzo KVM, BIOS seabios-1.7.5-11.vz7.4 04/01/2014 task: ffff880137786440 task.stack: ffffc90000ba8000 RIP: 0010:kfree_debugcheck+0x25/0x2a RSP: 0018:ffffc90000babde0 EFLAGS: 00010082 RAX: 0000000000000034 RBX: ac1fa1d106742a5a RCX: 0000000000000007 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88013f3ccb40 RBP: ffffc90000babde8 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000fcb76420 R11: 00000000725172ed R12: 0000000000000282 R13: ffffffff8150e766 R14: ffff88013a145e00 R15: 0000000000000001 FS: 00007fb09384bf40(0000) GS:ffff88013f200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd0172f9e40 CR3: 0000000137fa9000 CR4: 00000000000006f0 Call Trace: kfree+0xc8/0x1b3 bio_integrity_free+0xc3/0x16b bio_free+0x25/0x66 bio_put+0x14/0x26 blkdev_issue_flush+0x7a/0x85 blkdev_fsync+0x35/0x42 vfs_fsync_range+0x8e/0x9f vfs_fsync+0x1c/0x1e do_fsync+0x31/0x4a SyS_fsync+0x10/0x14 entry_SYSCALL_64_fastpath+0x1f/0xc2 Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: Martin K. Petersen Signed-off-by: Dmitry Monakhov Signed-off-by: Jens Axboe

block: Avoid that blk_exit_rl() triggers a use-after-free

2017-06-01T19:07:55Z

Since the introduction of .init_rq_fn() and .exit_rq_fn() it is essential that the memory allocated for struct request_queue stays around until all blk_exit_rl() calls have finished. Hence make blk_init_rl() take a reference on struct request_queue. This patch fixes the following crash: general protection fault: 0000 [#2] SMP CPU: 3 PID: 28 Comm: ksoftirqd/3 Tainted: G D 4.12.0-rc2-dbg+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 task: ffff88013a108040 task.stack: ffffc9000071c000 RIP: 0010:free_request_size+0x1a/0x30 RSP: 0018:ffffc9000071fd38 EFLAGS: 00010202 RAX: 6b6b6b6b6b6b6b6b RBX: ffff880067362a88 RCX: 0000000000000003 RDX: ffff880067464178 RSI: ffff880067362a88 RDI: ffff880135ea4418 RBP: ffffc9000071fd40 R08: 0000000000000000 R09: 0000000100180009 R10: ffffc9000071fd38 R11: ffffffff81110800 R12: ffff88006752d3d8 R13: ffff88006752d3d8 R14: ffff88013a108040 R15: 000000000000000a FS: 0000000000000000(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa8ec1edb00 CR3: 0000000138ee8000 CR4: 00000000001406e0 Call Trace: mempool_destroy.part.10+0x21/0x40 mempool_destroy+0xe/0x10 blk_exit_rl+0x12/0x20 blkg_free+0x4d/0xa0 __blkg_release_rcu+0x59/0x170 rcu_process_callbacks+0x260/0x4e0 __do_softirq+0x116/0x250 smpboot_thread_fn+0x123/0x1e0 kthread+0x109/0x140 ret_from_fork+0x31/0x40 Fixes: commit e9c787e65c0c ("scsi: allocate scsi_cmnd structures as part of struct request") Signed-off-by: Bart Van Assche Acked-by: Tejun Heo Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Cc: Jan Kara Cc: # v4.11+ Signed-off-by: Jens Axboe