Re: [PATCH v2 0/2] blk/nvme: fix NULL deref in rq_qos_done_bio() on multipath failover

Chaitanya Kulkarni
2026-03-10T05:43:47Z

On 2/25/26 19:12, Chaitanya Kulkarni wrote:
> Hi,
>
> When a bio is processed on a path's request queue with rq_qos enabled,
> it gets BIO_QOS_THROTTLED or BIO_QOS_MERGED flags set. During NVMe
> multipath failover, nvme_failover_req() redirects the bio's bi_bdev to
> the multipath head's disk via bio_set_dev(), but the BIO_QOS flags are
> left intact.
>
> This series moves bio queue transition code into blk_steal_bios()
> and adds a patch to clears BIO_QOS_THROTTLED and BIO_QOS_MERGED flags
> in blk_steal_bios().
>
> -ck
>
> v1->v2 https://lore.kernel.org/all/20251124070142.GA17632@lst.de/:
>
> * Add a new patch to move the bio flag fixup loop from nvme_failover_req()
> into blk_steal_bios() rather than adding it only in the NVMe multipath
> path. (Christoph)
>
> Chaitanya Kulkarni (2):
> block: move bio queue-transition flag fixups into blk_steal_bios()
> block: clear BIO_QOS flags in blk_steal_bios()
>
> block/blk-mq.c | 19 +++++++++++++++++++
> drivers/nvme/host/multipath.c | 15 +--------------
> 2 files changed, 20 insertions(+), 14 deletions(-)
>
Gentle ping on this how should we merge nvme or block tree ?

-ck