A regression of cmd dev -d/-D noticed on some vmcores as:
dev: invalid structure member offset: blk_mq_tag_set_shared_tags
FILE: dev.c LINE: 4468 FUNCTION: blk_mq_queue_tag_busy_iter()
MAJOR GENDISK NAME REQUEST_QUEUE TOTAL ASYNC SYNC
[crash] error trace: 91aa85 => 91a552 => 94d6ba => 94d647
94d647: OFFSET_verify.part.0+55
94d6ba: OFFSET_verify+42
91a552: get_diskio_1+2194
91aa85: display_all_diskio+1253
The root cause is, though upstream kernel have defined BLK_MQ_F_TAG_HCTX_SHARED
as (1 << 3), the value might be set different, e.g. [1]. So a single
blk_mq_is_shared_tags() check is not sufficient. This patch will add shared_tags
member check within blk_mq_tag_set struct as an enhancment.
[1]:
https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-8/-/blob/c8s/include/linux/blk-mq.h?ref_type=heads#L321
Fixes: 62486400d35b ("Add blk_mq shared tags support for dev -d/-D")
Signed-off-by: Tao Liu <[email protected]>
---
dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/dev.c b/dev.c
index 8391d71..27318e8 100644
--- a/dev.c
+++ b/dev.c
@@ -4464,7 +4464,7 @@ static void blk_mq_queue_tag_busy_iter(ulong q, ulong
*hctx, uint cnt,
readmem(addr + OFFSET(blk_mq_tag_set_flags), KVADDR,
&flags, sizeof(uint), "blk_mq_tag_set.flags", RETURN_ON_ERROR);
- if (blk_mq_is_shared_tags(flags)) {
+ if (blk_mq_is_shared_tags(flags) &&
VALID_MEMBER(blk_mq_tag_set_shared_tags)) {
addr = addr + OFFSET(blk_mq_tag_set_shared_tags);
queue_for_each_hw_ctx(q, addr, bitmap_tags_is_ptr, dio);
return;
--
2.47.0
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