From: Yu Kuai yukuai3@huawei.com

hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I65K8D CVE: NA

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Now that address of request_wrapper is caculated by address of request plus cmd_size, if cmd_size is not aligned to 8 bytes, request_wrapper will end up not aligned to 8 bytes as well, which will crash in arm64 because assembly instruction casal requires that operand address is aligned to 8 bytes:

Internal error: Oops: 96000021 [#1] SMP pc : blk_account_io_latency+0x54/0x134 Call trace: blk_account_io_latency+0x54/0x134 blk_account_io_done+0x3c/0x4c __blk_mq_end_request+0x78/0x134 scsi_end_request+0xcc/0x1f0 scsi_io_completion+0x88/0x240 scsi_finish_command+0x104/0x140 scsi_softirq_done+0x90/0x180 blk_mq_complete_request+0x5c/0x70 scsi_mq_done+0x4c/0x100

Fix the problem by declaring request_wrapper as aligned to cachline, and placing it before request.

Fixes: 82327165da5c ("blk-mq: don't access request_wrapper if request is not allocated from block layer") Signed-off-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Hou Tao houtao1@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- block/blk-flush.c | 8 +++++--- block/blk-mq.c | 2 +- block/blk-mq.h | 9 +++------ 3 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/block/blk-flush.c b/block/blk-flush.c index 65753f781c20..093c581a2651 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -470,6 +470,7 @@ struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size, gfp_t flags) { struct blk_flush_queue *fq; + struct request_wrapper *wrapper; int rq_sz = sizeof(struct request) + sizeof(struct request_wrapper);

fq = kzalloc_node(sizeof(*fq), flags, node); @@ -479,10 +480,11 @@ struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size, spin_lock_init(&fq->mq_flush_lock);

rq_sz = round_up(rq_sz + cmd_size, cache_line_size()); - fq->flush_rq = kzalloc_node(rq_sz, flags, node); - if (!fq->flush_rq) + wrapper = kzalloc_node(rq_sz, flags, node); + if (!wrapper) goto fail_rq;

+ fq->flush_rq = (struct request *)(wrapper + 1); INIT_LIST_HEAD(&fq->flush_queue[0]); INIT_LIST_HEAD(&fq->flush_queue[1]); INIT_LIST_HEAD(&fq->flush_data_in_flight); @@ -501,7 +503,7 @@ void blk_free_flush_queue(struct blk_flush_queue *fq) if (!fq) return;

- kfree(fq->flush_rq); + kfree(request_to_wrapper(fq->flush_rq)); kfree(fq); }

diff --git a/block/blk-mq.c b/block/blk-mq.c index 1c4a4e197e65..ffabe9c3de31 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2642,7 +2642,7 @@ static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, to_do = min(entries_per_page, depth - i); left -= to_do * rq_size; for (j = 0; j < to_do; j++) { - struct request *rq = p; + struct request *rq = p + sizeof(struct request_wrapper);

tags->static_rqs[i] = rq; if (blk_mq_init_request(set, rq, hctx_idx, node)) { diff --git a/block/blk-mq.h b/block/blk-mq.h index 6254abe9c112..dcb2077e4db6 100644 --- a/block/blk-mq.h +++ b/block/blk-mq.h @@ -40,14 +40,11 @@ struct blk_mq_ctx { struct request_wrapper { /* Time that I/O was counted in part_get_stat_info(). */ u64 stat_time_ns; -}; +} ____cacheline_aligned_in_smp;

-static inline struct request_wrapper *request_to_wrapper(struct request *rq) +static inline struct request_wrapper *request_to_wrapper(void *rq) { - unsigned long addr = (unsigned long)rq; - - addr += sizeof(*rq) + rq->q->tag_set->cmd_size; - return (struct request_wrapper *)addr; + return rq - sizeof(struct request_wrapper); }

void blk_mq_exit_queue(struct request_queue *q);