kernel/drivers/block/null_blk_main.c, branch linux-5.1.y

block: null_blk: fix race condition for null_del_dev

2019-07-26T07:12:35Z

[ Upstream commit 7602843fd873cae43a444b83b14dfdd114a9659c ] Dulicate call of null_del_dev() will trigger null pointer error like below. The reason is a race condition between nullb_device_power_store() and nullb_group_drop_item(). CPU#0 CPU#1 ---------------- ----------------- do_rmdir() >configfs_rmdir() >client_drop_item() >nullb_group_drop_item() nullb_device_power_store() >null_del_dev() >test_and_clear_bit(NULLB_DEV_FL_UP >null_del_dev() ^^^^^ Duplicated null_dev_dev() triger null pointer error >clear_bit(NULLB_DEV_FL_UP The fix could be keep the sequnce of clear NULLB_DEV_FL_UP and null_del_dev(). [ 698.613600] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 [ 698.613608] #PF error: [normal kernel read fault] [ 698.613611] PGD 0 P4D 0 [ 698.613619] Oops: 0000 [#1] SMP PTI [ 698.613627] CPU: 3 PID: 6382 Comm: rmdir Not tainted 5.0.0+ #35 [ 698.613631] Hardware name: LENOVO 20LJS2EV08/20LJS2EV08, BIOS R0SET33W (1.17 ) 07/18/2018 [ 698.613644] RIP: 0010:null_del_dev+0xc/0x110 [null_blk] [ 698.613649] Code: 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b eb 97 e8 47 bb 2a e8 0f 1f 80 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 54 53 <8b> 77 18 48 89 fb 4c 8b 27 48 c7 c7 40 57 1e c1 e8 bf c7 cb e8 48 [ 698.613654] RSP: 0018:ffffb887888bfde0 EFLAGS: 00010286 [ 698.613659] RAX: 0000000000000000 RBX: ffff9d436d92bc00 RCX: ffff9d43a9184681 [ 698.613663] RDX: ffffffffc11e5c30 RSI: 0000000068be6540 RDI: 0000000000000000 [ 698.613667] RBP: ffffb887888bfdf0 R08: 0000000000000001 R09: 0000000000000000 [ 698.613671] R10: ffffb887888bfdd8 R11: 0000000000000f16 R12: ffff9d436d92bc08 [ 698.613675] R13: ffff9d436d94e630 R14: ffffffffc11e5088 R15: ffffffffc11e5000 [ 698.613680] FS: 00007faa68be6540(0000) GS:ffff9d43d14c0000(0000) knlGS:0000000000000000 [ 698.613685] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 698.613689] CR2: 0000000000000018 CR3: 000000042f70c002 CR4: 00000000003606e0 [ 698.613693] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 698.613697] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 698.613700] Call Trace: [ 698.613712] nullb_group_drop_item+0x50/0x70 [null_blk] [ 698.613722] client_drop_item+0x29/0x40 [ 698.613728] configfs_rmdir+0x1ed/0x300 [ 698.613738] vfs_rmdir+0xb2/0x130 [ 698.613743] do_rmdir+0x1c7/0x1e0 [ 698.613750] __x64_sys_rmdir+0x17/0x20 [ 698.613759] do_syscall_64+0x5a/0x110 [ 698.613768] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Signed-off-by: Bob Liu Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

null_blk: prevent crash from bad home_node value

2019-04-06T16:51:08Z

At module load, if the selected home_node value is greater than the available numa nodes, the system will crash in __alloc_pages_nodemask() due to a bad paging request. Prevent this user error crash by detecting the bad value, logging an error, and setting g_home_node back to the default of NUMA_NO_NODE. Signed-off-by: John Pittman Signed-off-by: Jens Axboe

null_blk: fix checking for REQ_FUA

2019-02-28T21:03:03Z

null_handle_bio() erroneously uses the bio_op macro which masks respective request flag bits including REQ_FUA out thus failing the check. Fix by checking bio->bi_opf directly. Signed-off-by: Heinz Mauelshagen Signed-off-by: Jens Axboe

block: kill QUEUE_FLAG_FLUSH_NQ

2019-02-09T22:40:24Z

We have various helpers for setting/clearing this flag, and also a helper to check if the queue supports queueable flushes or not. But nobody uses them anymore, kill it with fire. Signed-off-by: Jens Axboe

block: remove the lock argument to blk_alloc_queue_node

2018-11-15T19:13:35Z

With the legacy request path gone there is no real need to override the queue_lock. Reviewed-by: Hannes Reinecke Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

null_blk: remove unused nullb device

2018-11-10T20:03:52Z

The compiler rightfully complains: drivers/block/null_blk_main.c: In function ‘null_complete_rq’: drivers/block/null_blk_main.c:647:16: warning: unused variable ‘nullb’ [-Wunused-variable] struct nullb *nullb = rq->q->queuedata; ^~~~~ Fixes: 49f6613632f9 ("nullb: remove leftover legacy request code") Signed-off-by: Jens Axboe

nullb: remove leftover legacy request code

2018-11-10T15:03:46Z

null_softirq_done_fn is only used for the blk-mq path, so remove the other branch. Also rename the function to better match the method name. Reviewed-by: Hannes Reinecke Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

null_blk: Add conventional zone configuration for zoned support

2018-11-07T20:41:50Z

Allow the creation of conventional zones by adding the zone_nr_conv configuration attribute. This new attribute is used only for zoned devices and indicates the number of conventional zones to create. The default value is 0. Since host-managed zoned block devices must always have at least one sequential zone, if the value of zone_nr_conv is larger than or equal to the total number of zones of the device nr_zones, zone_nr_conv is automatically changed to nr_zones - 1. Reviewed-by: Matias Bjorling Reviewed-by: Damien Le Moal Signed-off-by: Masato Suzuki Signed-off-by: Jens Axboe

block: Introduce blk_revalidate_disk_zones()

2018-10-25T17:17:40Z

Drivers exposing zoned block devices have to initialize and maintain correctness (i.e. revalidate) of the device zone bitmaps attached to the device request queue (seq_zones_bitmap and seq_zones_wlock). To simplify coding this, introduce a generic helper function blk_revalidate_disk_zones() suitable for most (and likely all) cases. This new function always update the seq_zones_bitmap and seq_zones_wlock bitmaps as well as the queue nr_zones field when called for a disk using a request based queue. For a disk using a BIO based queue, only the number of zones is updated since these queues do not have schedulers and so do not need the zone bitmaps. With this change, the zone bitmap initialization code in sd_zbc.c can be replaced with a call to this function in sd_zbc_read_zones(), which is called from the disk revalidate block operation method. A call to blk_revalidate_disk_zones() is also added to the null_blk driver for devices created with the zoned mode enabled. Finally, to ensure that zoned devices created with dm-linear or dm-flakey expose the correct number of zones through sysfs, a call to blk_revalidate_disk_zones() is added to dm_table_set_restrictions(). The zone bitmaps allocated and initialized with blk_revalidate_disk_zones() are freed automatically from __blk_release_queue() using the block internal function blk_queue_free_zone_bitmaps(). Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Reviewed-by: Mike Snitzer Signed-off-by: Damien Le Moal Signed-off-by: Jens Axboe

block: add a report_zones method

2018-10-25T17:17:40Z

Dispatching a report zones command through the request queue is a major pain due to the command reply payload rewriting necessary. Given that blkdev_report_zones() is executing everything synchronously, implement report zones as a block device file operation instead, allowing major simplification of the code in many places. sd, null-blk, dm-linear and dm-flakey being the only block device drivers supporting exposing zoned block devices, these drivers are modified to provide the device side implementation of the report_zones() block device file operation. For device mappers, a new report_zones() target type operation is defined so that the upper block layer calls blkdev_report_zones() can be propagated down to the underlying devices of the dm targets. Implementation for this new operation is added to the dm-linear and dm-flakey targets. Reviewed-by: Hannes Reinecke Signed-off-by: Christoph Hellwig [Damien] * Changed method block_device argument to gendisk * Various bug fixes and improvements * Added support for null_blk, dm-linear and dm-flakey. Reviewed-by: Martin K. Petersen Reviewed-by: Mike Snitzer Signed-off-by: Damien Le Moal Signed-off-by: Jens Axboe