[PATCH 0/4] block: fix race between adding wbt and normal IO

Hello,

Yi reported several kernel panics on:

[16687.001777] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
...
[16687.163549] pc : __rq_qos_track+0x38/0x60

or

[  997.690455] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020
...
[  997.850347] pc : __rq_qos_done+0x2c/0x50

Turns out it is caused by race between adding wbt and normal IO.

Fix the issue by moving wbt allocation/addition into blk_alloc_queue().


Ming Lei (4):
  block: split wbt_init() into two parts
  block: move wbt allocation into blk_alloc_queue
  block: reuse wbt_set_min_lat for setting wbt->min_lat_nsec
  block: mark queue init done at the end of blk_register_queue

 block/blk-core.c       |  6 +++++
 block/blk-mq-debugfs.c |  3 +++
 block/blk-sysfs.c      | 53 ++++++++++++++----------------------------
 block/blk-wbt.c        | 42 +++++++++++++++++++++++----------
 block/blk-wbt.h        | 14 +++++++----
 5 files changed, 66 insertions(+), 52 deletions(-)

Cc: Yi Zhang <redacted>

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2.29.2