kernel/linux.git/block, branch v5.4.7

iocost: over-budget forced IOs should schedule async delay

2019-12-31T15:46:19+00:00

commit d7bd15a138aef3be227818aad9c501e43c89c8c5 upstream. When over-budget IOs are force-issued through root cgroup, iocg_kick_delay() adjusts the async delay accordingly but doesn't actually schedule async throttle for the issuing task. This bug is pretty well masked because sooner or later the offending threads are gonna get directly throttled on regular IOs or have async delay scheduled by mem_cgroup_throttle_swaprate(). However, it can affect control quality on filesystem metadata heavy operations. Let's fix it by invoking blkcg_schedule_throttle() when iocg_kick_delay() says async delay is needed. Signed-off-by: Tejun Heo Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Cc: stable@vger.kernel.org Reported-by: Josef Bacik Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block: fix "check bi_size overflow before merge"

2019-12-21T10:04:32+00:00

commit cc90bc68422318eb8e75b15cd74bc8d538a7df29 upstream. This partially reverts commit e3a5d8e386c3fb973fa75f2403622a8f3640ec06. Commit e3a5d8e386c3 ("check bi_size overflow before merge") adds a bio_full check to __bio_try_merge_page. This will cause __bio_try_merge_page to fail when the last bi_io_vec has been reached. Instead, what we want here is only the bi_size overflow check. Fixes: e3a5d8e386c3 ("block: check bi_size overflow before merge") Cc: stable@vger.kernel.org # v5.4+ Reviewed-by: Ming Lei Signed-off-by: Andreas Gruenbacher Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

blk-mq: make sure that line break can be printed

2019-12-17T18:56:53+00:00

commit d2c9be89f8ebe7ebcc97676ac40f8dec1cf9b43a upstream. 8962842ca5ab ("blk-mq: avoid sysfs buffer overflow with too many CPU cores") avoids sysfs buffer overflow, and reserves one character for line break. However, the last snprintf() doesn't get correct 'size' parameter passed in, so fixed it. Fixes: 8962842ca5ab ("blk-mq: avoid sysfs buffer overflow with too many CPU cores") Signed-off-by: Ming Lei Signed-off-by: Jens Axboe Cc: Nobuhiro Iwamatsu Signed-off-by: Greg Kroah-Hartman

blk-mq: avoid sysfs buffer overflow with too many CPU cores

2019-12-17T18:56:14+00:00

commit 8962842ca5abdcf98e22ab3b2b45a103f0408b95 upstream. It is reported that sysfs buffer overflow can be triggered if the system has too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs of hctx via /sys/block/$DEV/mq/$N/cpu_list. Use snprintf to avoid the potential buffer overflow. This version doesn't change the attribute format, and simply stops showing CPU numbers if the buffer is going to overflow. Cc: stable@vger.kernel.org Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load") Signed-off-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

iocost: check active_list of all the ancestors in iocg_activate()

2019-11-14T20:56:54+00:00

There is a bug that checking the same active_list over and over again in iocg_activate(). The intention of the code was checking whether all the ancestors and self have already been activated. So fix it. Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Acked-by: Tejun Heo Signed-off-by: Jiufei Xue Signed-off-by: Jens Axboe

block, bfq: deschedule empty bfq_queues not referred by any process

2019-11-14T14:00:54+00:00

Since commit 3726112ec731 ("block, bfq: re-schedule empty queues if they deserve I/O plugging"), to prevent the service guarantees of a bfq_queue from being violated, the bfq_queue may be left busy, i.e., scheduled for service, even if empty (see comments in __bfq_bfqq_expire() for details). But, if no process will send requests to the bfq_queue any longer, then there is no point in keeping the bfq_queue scheduled for service. In addition, keeping the bfq_queue scheduled for service, but with no process reference any longer, may cause the bfq_queue to be freed when descheduled from service. But this is assumed to never happen, and causes a UAF if it happens. This, in turn, caused crashes [1, 2]. This commit fixes this issue by descheduling an empty bfq_queue when it remains with not process reference. [1] https://bugzilla.redhat.com/show_bug.cgi?id=1767539 [2] https://bugzilla.kernel.org/show_bug.cgi?id=205447 Fixes: 3726112ec731 ("block, bfq: re-schedule empty queues if they deserve I/O plugging") Reported-by: Chris Evich Reported-by: Patrick Dung Reported-by: Thorsten Schubert Tested-by: Thorsten Schubert Tested-by: Oleksandr Natalenko Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe

block: check bi_size overflow before merge

2019-11-12T14:26:27+00:00

__bio_try_merge_page() may merge a page to bio without bio_full() check and cause bi_size overflow. The overflow typically ends up with sd_init_command() warning on zero segment request with call trace like this: ------------[ cut here ]------------ WARNING: CPU: 2 PID: 1986 at drivers/scsi/scsi_lib.c:1025 scsi_init_io+0x156/0x180 CPU: 2 PID: 1986 Comm: kworker/2:1H Kdump: loaded Not tainted 5.4.0-rc7 #1 Workqueue: kblockd blk_mq_run_work_fn RIP: 0010:scsi_init_io+0x156/0x180 RSP: 0018:ffffa11487663bf0 EFLAGS: 00010246 RAX: 00000000002be0a0 RBX: ffff8e6e9ff30118 RCX: 0000000000000000 RDX: 00000000ffffffe1 RSI: 0000000000000000 RDI: ffff8e6e9ff30118 RBP: ffffa11487663c18 R08: ffffa11487663d28 R09: ffff8e6e9ff30150 R10: 0000000000000001 R11: 0000000000000000 R12: ffff8e6e9ff30000 R13: 0000000000000001 R14: ffff8e74a1cf1800 R15: ffff8e6e9ff30000 FS: 0000000000000000(0000) GS:ffff8e6ea7680000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff18cf0fe8 CR3: 0000000659f0a001 CR4: 00000000001606e0 Call Trace: sd_init_command+0x326/0xb40 [sd_mod] scsi_queue_rq+0x502/0xaa0 ? blk_mq_get_driver_tag+0xe7/0x120 blk_mq_dispatch_rq_list+0x256/0x5a0 ? elv_rb_del+0x24/0x30 ? deadline_remove_request+0x7b/0xc0 blk_mq_do_dispatch_sched+0xa3/0x140 blk_mq_sched_dispatch_requests+0xfb/0x170 __blk_mq_run_hw_queue+0x81/0x130 blk_mq_run_work_fn+0x1b/0x20 process_one_work+0x179/0x390 worker_thread+0x4f/0x3e0 kthread+0x105/0x140 ? max_active_store+0x80/0x80 ? kthread_bind+0x20/0x20 ret_from_fork+0x35/0x40 ---[ end trace f9036abf5af4a4d3 ]--- blk_update_request: I/O error, dev sdd, sector 2875552 op 0x1:(WRITE) flags 0x0 phys_seg 0 prio class 0 XFS (sdd1): writeback error on sector 2875552 __bio_try_merge_page() should check the overflow before actually doing merge. Fixes: 07173c3ec276c ("block: enable multipage bvecs") Reviewed-by: Christoph Hellwig Reviewed-by: Ming Lei Reviewed-by: Hannes Reinecke Signed-off-by: Jun'ichi Nomura Signed-off-by: Jens Axboe

blkcg: make blkcg_print_stat() print stats only for online blkgs

2019-11-07T00:08:38+00:00

blkcg_print_stat() iterates blkgs under RCU and doesn't test whether the blkg is online. This can call into pd_stat_fn() on a pd which is still being initialized leading to an oops. The heaviest operation - recursively summing up rwstat counters - is already done while holding the queue_lock. Expand queue_lock to cover the other operations and skip the blkg if it isn't online yet. The online state is protected by both blkcg and queue locks, so this guarantees that only online blkgs are processed. Signed-off-by: Tejun Heo Reported-by: Roman Gushchin Cc: Josef Bacik Fixes: 903d23f0a354 ("blk-cgroup: allow controllers to output their own stats") Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Jens Axboe

iocost: don't nest spin_lock_irq in ioc_weight_write()

2019-10-31T17:40:57+00:00

This code causes a static analysis warning: block/blk-iocost.c:2113 ioc_weight_write() error: double lock 'irq' We disable IRQs in blkg_conf_prep() and re-enable them in blkg_conf_finish(). IRQ disable/enable should not be nested because that means the IRQs will be enabled at the first unlock instead of the second one. Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Acked-by: Tejun Heo Signed-off-by: Dan Carpenter Signed-off-by: Jens Axboe

blk-rq-qos: fix first node deletion of rq_qos_del()

2019-10-15T16:13:13+00:00

rq_qos_del() incorrectly assigns the node being deleted to the head if it was the first on the list in the !prev path. Fix it by iterating with ** instead. Signed-off-by: Tejun Heo Cc: Josef Bacik Fixes: a79050434b45 ("blk-rq-qos: refactor out common elements of blk-wbt") Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Jens Axboe