linux-toradex.git/block, branch v6.13-rc2

blk-mq: move cpuhp callback registering out of q->sysfs_lock

2024-12-06T16:48:46+00:00

Registering and unregistering cpuhp callback requires global cpu hotplug lock,
which is used everywhere. Meantime q->sysfs_lock is used in block layer
almost everywhere.

It is easy to trigger lockdep warning[1] by connecting the two locks.

Fix the warning by moving blk-mq's cpuhp callback registering out of
q->sysfs_lock. Add one dedicated global lock for covering registering &
unregistering hctx's cpuhp, and it is safe to do so because hctx is
guaranteed to be live if our request_queue is live.

[1] https://lore.kernel.org/lkml/Z04pz3AlvI4o0Mr8@agluck-desk3/

Cc: Reinette Chatre 
Cc: Fenghua Yu 
Cc: Peter Newman 
Cc: Babu Moger 
Reported-by: Luck Tony 
Signed-off-by: Ming Lei 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/r/20241206111611.978870-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe

blk-mq: register cpuhp callback after hctx is added to xarray table

2024-12-06T16:48:46+00:00

We need to retrieve 'hctx' from xarray table in the cpuhp callback, so the
callback should be registered after this 'hctx' is added to xarray table.

Cc: Reinette Chatre 
Cc: Fenghua Yu 
Cc: Peter Newman 
Cc: Babu Moger 
Cc: Luck Tony 
Signed-off-by: Ming Lei 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/r/20241206111611.978870-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe

Merge tag 'block-6.13-20242901' of git://git.kernel.dk/linux

2024-11-30T23:47:29+00:00

Pull more block updates from Jens Axboe:

 - NVMe pull request via Keith:
      - Use correct srcu list traversal (Breno)
      - Scatter-gather support for metadata (Keith)
      - Fabrics shutdown race condition fix (Nilay)
      - Persistent reservations updates (Guixin)

 - Add the required bits for MD atomic write support for raid0/1/10

 - Correct return value for unknown opcode in ublk

 - Fix deadlock with zone revalidation

 - Fix for the io priority request vs bio cleanups

 - Use the correct unsigned int type for various limit helpers

 - Fix for a race in loop

 - Cleanup blk_rq_prep_clone() to prevent uninit-value warning and make
   it easier for actual humans to read

 - Fix potential UAF when iterating tags

 - A few fixes for bfq-iosched UAF issues

 - Fix for brd discard not decrementing the allocated page count

 - Various little fixes and cleanups

* tag 'block-6.13-20242901' of git://git.kernel.dk/linux: (36 commits)
  brd: decrease the number of allocated pages which discarded
  block, bfq: fix bfqq uaf in bfq_limit_depth()
  block: Don't allow an atomic write be truncated in blkdev_write_iter()
  mq-deadline: don't call req_get_ioprio from the I/O completion handler
  block: Prevent potential deadlock in blk_revalidate_disk_zones()
  block: Remove extra part pointer NULLify in blk_rq_init()
  nvme: tuning pr code by using defined structs and macros
  nvme: introduce change ptpl and iekey definition
  block: return bool from get_disk_ro and bdev_read_only
  block: remove a duplicate definition for bdev_read_only
  block: return bool from blk_rq_aligned
  block: return unsigned int from blk_lim_dma_alignment_and_pad
  block: return unsigned int from queue_dma_alignment
  block: return unsigned int from bdev_io_opt
  block: req->bio is always set in the merge code
  block: don't bother checking the data direction for merges
  block: blk-mq: fix uninit-value in blk_rq_prep_clone and refactor
  Revert "block, bfq: merge bfq_release_process_ref() into bfq_put_cooperator()"
  md/raid10: Atomic write support
  md/raid1: Atomic write support
  ...

block, bfq: fix bfqq uaf in bfq_limit_depth()

2024-11-29T15:42:14+00:00

Set new allocated bfqq to bic or remove freed bfqq from bic are both
protected by bfqd->lock, however bfq_limit_depth() is deferencing bfqq
from bic without the lock, this can lead to UAF if the io_context is
shared by multiple tasks.

For example, test bfq with io_uring can trigger following UAF in v6.6:

==================================================================
BUG: KASAN: slab-use-after-free in bfqq_group+0x15/0x50

Call Trace:
 
 dump_stack_lvl+0x47/0x80
 print_address_description.constprop.0+0x66/0x300
 print_report+0x3e/0x70
 kasan_report+0xb4/0xf0
 bfqq_group+0x15/0x50
 bfqq_request_over_limit+0x130/0x9a0
 bfq_limit_depth+0x1b5/0x480
 __blk_mq_alloc_requests+0x2b5/0xa00
 blk_mq_get_new_requests+0x11d/0x1d0
 blk_mq_submit_bio+0x286/0xb00
 submit_bio_noacct_nocheck+0x331/0x400
 __block_write_full_folio+0x3d0/0x640
 writepage_cb+0x3b/0xc0
 write_cache_pages+0x254/0x6c0
 write_cache_pages+0x254/0x6c0
 do_writepages+0x192/0x310
 filemap_fdatawrite_wbc+0x95/0xc0
 __filemap_fdatawrite_range+0x99/0xd0
 filemap_write_and_wait_range.part.0+0x4d/0xa0
 blkdev_read_iter+0xef/0x1e0
 io_read+0x1b6/0x8a0
 io_issue_sqe+0x87/0x300
 io_wq_submit_work+0xeb/0x390
 io_worker_handle_work+0x24d/0x550
 io_wq_worker+0x27f/0x6c0
 ret_from_fork_asm+0x1b/0x30
 

Allocated by task 808602:
 kasan_save_stack+0x1e/0x40
 kasan_set_track+0x21/0x30
 __kasan_slab_alloc+0x83/0x90
 kmem_cache_alloc_node+0x1b1/0x6d0
 bfq_get_queue+0x138/0xfa0
 bfq_get_bfqq_handle_split+0xe3/0x2c0
 bfq_init_rq+0x196/0xbb0
 bfq_insert_request.isra.0+0xb5/0x480
 bfq_insert_requests+0x156/0x180
 blk_mq_insert_request+0x15d/0x440
 blk_mq_submit_bio+0x8a4/0xb00
 submit_bio_noacct_nocheck+0x331/0x400
 __blkdev_direct_IO_async+0x2dd/0x330
 blkdev_write_iter+0x39a/0x450
 io_write+0x22a/0x840
 io_issue_sqe+0x87/0x300
 io_wq_submit_work+0xeb/0x390
 io_worker_handle_work+0x24d/0x550
 io_wq_worker+0x27f/0x6c0
 ret_from_fork+0x2d/0x50
 ret_from_fork_asm+0x1b/0x30

Freed by task 808589:
 kasan_save_stack+0x1e/0x40
 kasan_set_track+0x21/0x30
 kasan_save_free_info+0x27/0x40
 __kasan_slab_free+0x126/0x1b0
 kmem_cache_free+0x10c/0x750
 bfq_put_queue+0x2dd/0x770
 __bfq_insert_request.isra.0+0x155/0x7a0
 bfq_insert_request.isra.0+0x122/0x480
 bfq_insert_requests+0x156/0x180
 blk_mq_dispatch_plug_list+0x528/0x7e0
 blk_mq_flush_plug_list.part.0+0xe5/0x590
 __blk_flush_plug+0x3b/0x90
 blk_finish_plug+0x40/0x60
 do_writepages+0x19d/0x310
 filemap_fdatawrite_wbc+0x95/0xc0
 __filemap_fdatawrite_range+0x99/0xd0
 filemap_write_and_wait_range.part.0+0x4d/0xa0
 blkdev_read_iter+0xef/0x1e0
 io_read+0x1b6/0x8a0
 io_issue_sqe+0x87/0x300
 io_wq_submit_work+0xeb/0x390
 io_worker_handle_work+0x24d/0x550
 io_wq_worker+0x27f/0x6c0
 ret_from_fork+0x2d/0x50
 ret_from_fork_asm+0x1b/0x30

Fix the problem by protecting bic_to_bfqq() with bfqd->lock.

CC: Jan Kara 
Fixes: 76f1df88bbc2 ("bfq: Limit number of requests consumed by each cgroup")
Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20241129091509.2227136-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe

block: Don't allow an atomic write be truncated in blkdev_write_iter()

2024-11-27T22:04:57+00:00

A write which goes past the end of the bdev in blkdev_write_iter() will
be truncated. Truncating cannot tolerated for an atomic write, so error
that condition.

Fixes: caf336f81b3a ("block: Add fops atomic write support")
Signed-off-by: John Garry 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20241127092318.632790-1-john.g.garry@oracle.com
Signed-off-by: Jens Axboe

mq-deadline: don't call req_get_ioprio from the I/O completion handler

2024-11-26T14:57:33+00:00

req_get_ioprio looks at req->bio to find the I/O priority, which is not
set when completing bios that the driver fully iterated through.

Stash away the dd_per_prio in the elevator private data instead of looking
it up again to optimize the code a bit while fixing the regression from
removing the per-request ioprio value.

Fixes: 6975c1a486a4 ("block: remove the ioprio field from struct request")
Reported-by: Chris Bainbridge 
Reported-by: Sam Protsenko 
Signed-off-by: Christoph Hellwig 
Tested-by: Chris Bainbridge 
Tested-by: Sam Protsenko 
Reviewed-by: Bart Van Assche 
Link: https://lore.kernel.org/r/20241126102136.619067-1-hch@lst.de
Signed-off-by: Jens Axboe

block: Prevent potential deadlock in blk_revalidate_disk_zones()

2024-11-26T14:56:43+00:00

The function blk_revalidate_disk_zones() calls the function
disk_update_zone_resources() after freezing the device queue. In turn,
disk_update_zone_resources() calls queue_limits_start_update() which
takes a queue limits mutex lock, resulting in the ordering:
q->q_usage_counter check -> q->limits_lock. However, the usual ordering
is to always take a queue limit lock before freezing the queue to commit
the limits updates, e.g., the code pattern:

lim = queue_limits_start_update(q);
...
blk_mq_freeze_queue(q);
ret = queue_limits_commit_update(q, &lim);
blk_mq_unfreeze_queue(q);

Thus, blk_revalidate_disk_zones() introduces a potential circular
locking dependency deadlock that lockdep sometimes catches with the
splat:

[   51.934109] ======================================================
[   51.935916] WARNING: possible circular locking dependency detected
[   51.937561] 6.12.0+ #2107 Not tainted
[   51.938648] ------------------------------------------------------
[   51.940351] kworker/u16:4/157 is trying to acquire lock:
[   51.941805] ffff9fff0aa0bea8 (&q->limits_lock){+.+.}-{4:4}, at: disk_update_zone_resources+0x86/0x170
[   51.944314]
               but task is already holding lock:
[   51.945688] ffff9fff0aa0b890 (&q->q_usage_counter(queue)#3){++++}-{0:0}, at: blk_revalidate_disk_zones+0x15f/0x340
[   51.948527]
               which lock already depends on the new lock.

[   51.951296]
               the existing dependency chain (in reverse order) is:
[   51.953708]
               -> #1 (&q->q_usage_counter(queue)#3){++++}-{0:0}:
[   51.956131]        blk_queue_enter+0x1c9/0x1e0
[   51.957290]        blk_mq_alloc_request+0x187/0x2a0
[   51.958365]        scsi_execute_cmd+0x78/0x490 [scsi_mod]
[   51.959514]        read_capacity_16+0x111/0x410 [sd_mod]
[   51.960693]        sd_revalidate_disk.isra.0+0x872/0x3240 [sd_mod]
[   51.962004]        sd_probe+0x2d7/0x520 [sd_mod]
[   51.962993]        really_probe+0xd5/0x330
[   51.963898]        __driver_probe_device+0x78/0x110
[   51.964925]        driver_probe_device+0x1f/0xa0
[   51.965916]        __driver_attach_async_helper+0x60/0xe0
[   51.967017]        async_run_entry_fn+0x2e/0x140
[   51.968004]        process_one_work+0x21f/0x5a0
[   51.968987]        worker_thread+0x1dc/0x3c0
[   51.969868]        kthread+0xe0/0x110
[   51.970377]        ret_from_fork+0x31/0x50
[   51.970983]        ret_from_fork_asm+0x11/0x20
[   51.971587]
               -> #0 (&q->limits_lock){+.+.}-{4:4}:
[   51.972479]        __lock_acquire+0x1337/0x2130
[   51.973133]        lock_acquire+0xc5/0x2d0
[   51.973691]        __mutex_lock+0xda/0xcf0
[   51.974300]        disk_update_zone_resources+0x86/0x170
[   51.975032]        blk_revalidate_disk_zones+0x16c/0x340
[   51.975740]        sd_zbc_revalidate_zones+0x73/0x160 [sd_mod]
[   51.976524]        sd_revalidate_disk.isra.0+0x465/0x3240 [sd_mod]
[   51.977824]        sd_probe+0x2d7/0x520 [sd_mod]
[   51.978917]        really_probe+0xd5/0x330
[   51.979915]        __driver_probe_device+0x78/0x110
[   51.981047]        driver_probe_device+0x1f/0xa0
[   51.982143]        __driver_attach_async_helper+0x60/0xe0
[   51.983282]        async_run_entry_fn+0x2e/0x140
[   51.984319]        process_one_work+0x21f/0x5a0
[   51.985873]        worker_thread+0x1dc/0x3c0
[   51.987289]        kthread+0xe0/0x110
[   51.988546]        ret_from_fork+0x31/0x50
[   51.989926]        ret_from_fork_asm+0x11/0x20
[   51.991376]
               other info that might help us debug this:

[   51.994127]  Possible unsafe locking scenario:

[   51.995651]        CPU0                    CPU1
[   51.996694]        ----                    ----
[   51.997716]   lock(&q->q_usage_counter(queue)#3);
[   51.998817]                                lock(&q->limits_lock);
[   52.000043]                                lock(&q->q_usage_counter(queue)#3);
[   52.001638]   lock(&q->limits_lock);
[   52.002485]
                *** DEADLOCK ***

Prevent this issue by moving the calls to blk_mq_freeze_queue() and
blk_mq_unfreeze_queue() around the call to queue_limits_commit_update()
in disk_update_zone_resources(). In case of revalidation failure, the
call to disk_free_zone_resources() in blk_revalidate_disk_zones()
is still done with the queue frozen as before.

Fixes: 843283e96e5a ("block: Fake max open zones limit when there is no limit")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20241126104705.183996-1-dlemoal@kernel.org
Signed-off-by: Jens Axboe

block: Remove extra part pointer NULLify in blk_rq_init()

2024-11-25T15:42:14+00:00

The rq->part pointer is already NULLified in the memset() call, so - like
for other pointers in rq - don't re-NULLify.

Signed-off-by: John Garry 
Link: https://lore.kernel.org/r/20241125100258.4172774-1-john.g.garry@oracle.com
Signed-off-by: Jens Axboe

block: req->bio is always set in the merge code

2024-11-20T02:06:57+00:00

As smatch, which is a lot smarter than me noticed.  So remove the checks
for it, and condense these checks a bit including the comments stating
the obvious.

Reported-by: Dan Carpenter 
Signed-off-by: Christoph Hellwig 
Reviewed-by: John Garry 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Johannes Thumshirn 
Link: https://lore.kernel.org/r/20241119161157.1328171-3-hch@lst.de
Signed-off-by: Jens Axboe

block: don't bother checking the data direction for merges

2024-11-20T02:06:57+00:00

Because it already is encoded in the opcode.

Signed-off-by: Christoph Hellwig 
Reviewed-by: John Garry 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Johannes Thumshirn 
Link: https://lore.kernel.org/r/20241119161157.1328171-2-hch@lst.de
Signed-off-by: Jens Axboe