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

Message ID 20210525080442.1896417-1-ming.lei@redhat.com (mailing list archive)
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Series block: fix race between adding wbt and normal IO | expand

Message

Ming Lei May 25, 2021, 8:04 a.m. UTC 
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 <yi.zhang@redhat.com>

Comments

Ming Lei June 4, 2021, 12:03 a.m. UTC | #1 
On Tue, May 25, 2021 at 04:04:38PM +0800, Ming Lei wrote:
> 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().

Hello Guys,

Ping...


Thanks,
Ming