On Tue, 26 Aug 2025, Zheng Qixing wrote:
> From: Zheng Qixing <[email protected]>
>
> Hello,
>
> During reliability testing of the dm module, we discovered two bugs when
> performing create/remove and suspend/resume operations at high frequency.
>
> Analysis revealed that race conditions between suspend and table load
> operations cause asymmetric handling of q->quiesce_depth and null pointer
> dereference issues with q->tag_set.
>
> To address the q->tag_set null pointer issue, patch 2 determines whether
> to perform certain suspend actions for request-based devices based on the
> existence of the table (map).
>
> For detailed information, please refer to the patch commits.
>
> Additionally, since modern Linux kernels have indeed transitioned to
> multi-queue as the default (and single-queue is largely deprecated),
> is using queue_is_mq() to determine dm_request_based() obsolete?
>
> Zheng Qixing (2):
> dm: fix queue start/stop imbalance under suspend/load/resume races
> dm: fix NULL pointer dereference in __dm_suspend()
>
> drivers/md/dm-core.h | 1 +
> drivers/md/dm.c | 13 ++++++++-----
> 2 files changed, 9 insertions(+), 5 deletions(-)
>
> --
> 2.39.2
Both patches applied, thanks.
Mikulas
