On 10/25/21 5:16 AM, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 2f111a6fd5b5 Merge tag 'ceph-for-5.15-rc7' of git://github.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=10dae330b00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=b2868748300e5cf6 > dashboard link: https://syzkaller.appspot.com/bug?extid=4f8bfd804b4a1f95b8f6 > compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2 > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+4f8bfd804b4a1f95b8f6@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KCSAN: data-race in sbitmap_queue_clear / sbitmap_queue_clear > > write to 0xffffe8ffffd145b8 of 4 bytes by interrupt on cpu 1: > sbitmap_queue_clear+0xca/0xf0 lib/sbitmap.c:606 > blk_mq_put_tag+0x82/0x90 > __blk_mq_free_request+0x114/0x180 block/blk-mq.c:507 > blk_mq_free_request+0x2c8/0x340 block/blk-mq.c:541 > __blk_mq_end_request+0x214/0x230 block/blk-mq.c:565 > blk_mq_end_request+0x37/0x50 block/blk-mq.c:574 > lo_complete_rq+0xca/0x170 drivers/block/loop.c:541 > blk_complete_reqs block/blk-mq.c:584 [inline] > blk_done_softirq+0x69/0x90 block/blk-mq.c:589 > __do_softirq+0x12c/0x26e kernel/softirq.c:558 > run_ksoftirqd+0x13/0x20 kernel/softirq.c:920 > smpboot_thread_fn+0x22f/0x330 kernel/smpboot.c:164 > kthread+0x262/0x280 kernel/kthread.c:319 > ret_from_fork+0x1f/0x30 > > write to 0xffffe8ffffd145b8 of 4 bytes by interrupt on cpu 0: > sbitmap_queue_clear+0xca/0xf0 lib/sbitmap.c:606 > blk_mq_put_tag+0x82/0x90 > __blk_mq_free_request+0x114/0x180 block/blk-mq.c:507 > blk_mq_free_request+0x2c8/0x340 block/blk-mq.c:541 > __blk_mq_end_request+0x214/0x230 block/blk-mq.c:565 > blk_mq_end_request+0x37/0x50 block/blk-mq.c:574 > lo_complete_rq+0xca/0x170 drivers/block/loop.c:541 > blk_complete_reqs block/blk-mq.c:584 [inline] > blk_done_softirq+0x69/0x90 block/blk-mq.c:589 > __do_softirq+0x12c/0x26e kernel/softirq.c:558 > run_ksoftirqd+0x13/0x20 kernel/softirq.c:920 > smpboot_thread_fn+0x22f/0x330 kernel/smpboot.c:164 > kthread+0x262/0x280 kernel/kthread.c:319 > ret_from_fork+0x1f/0x30 This is just a per-cpu alloc hint, it's racy by nature. What's the preferred way to silence these? -- Jens Axboe
