Alrighty, here is v3 with all the BUG_*() crap removed, and moving to just create the debugfs directory needed for the partitions as well at initialization. This allows us to get rid of the pesky debugfs_lookup() calls which has made this code very awkward, and allowed us to find surprising bugs when we went with an asynchronous request_queue removal. I'll note that I still see this: debugfs: Directory 'loop0' with parent 'block' already present! But only for break-blktrace [0] run_0004.sh. But since we don't have any more races with blktrace, this has pushed me to look into disk registration / deletion. I'll be posting patches soon about some changes to help with that, on the error handling. If, after these patches, you however find the root cause to this let me know! Also, if folks don't disagree, I'll likely follow up to just merge break-blktrace as a self-test for blktrace. We can later expand on it upstream instead. These patches are based on linux-next tag next-20200428, you can find the code on my 20200428-blktrace-fixes branch [1]. [0] https://github.com/mcgrof/break-blktrace [1] https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git/log/?h=20200428-blktrace-fixes Luis Chamberlain (6): block: revert back to synchronous request_queue removal block: move main block debugfs initialization to its own file blktrace: move blktrace debugfs creation to helper function blktrace: fix debugfs use after free blktrace: break out of blktrace setup on concurrent calls loop: be paranoid on exit and prevent new additions / removals block/Makefile | 1 + block/blk-core.c | 32 ++++++++++++---- block/blk-debugfs.c | 44 ++++++++++++++++++++++ block/blk-mq-debugfs.c | 5 --- block/blk-sysfs.c | 47 ++++++++++++----------- block/blk.h | 18 +++++++++ block/genhd.c | 73 +++++++++++++++++++++++++++++++++++- block/partitions/core.c | 3 ++ drivers/block/loop.c | 4 ++ drivers/scsi/sg.c | 2 + include/linux/blkdev.h | 7 ++-- include/linux/blktrace_api.h | 1 - include/linux/genhd.h | 18 +++++++++ kernel/trace/blktrace.c | 39 ++++++++++++++++--- 14 files changed, 249 insertions(+), 45 deletions(-) create mode 100644 block/blk-debugfs.c -- 2.25.1
