syzbot

netlink: 4 bytes leftover after parsing attributes in process `syz.1.2094'.
netlink: 36 bytes leftover after parsing attributes in process `syz.1.2094'.
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc6-syzkaller-00059-g643e2e259c2b #0 Not tainted
------------------------------------------------------
syz.1.2094/15337 is trying to acquire lock:
ffff8880262fdf00 (&q->limits_lock){+.+.}-{4:4}, at: queue_limits_start_update include/linux/blkdev.h:947 [inline]
ffff8880262fdf00 (&q->limits_lock){+.+.}-{4:4}, at: __nbd_set_size+0x2c0/0x730 drivers/block/nbd.c:351

but task is already holding lock:
ffff8880262fd8b0 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: nbd_set_size drivers/block/nbd.c:387 [inline]
ffff8880262fd8b0 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: nbd_start_device+0x8ef/0xd70 drivers/block/nbd.c:1456

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (&q->q_usage_counter(io)#49){++++}-{0:0}:
       bio_queue_enter block/blk.h:75 [inline]
       blk_mq_submit_bio+0x1fb6/0x24c0 block/blk-mq.c:3090
       __submit_bio+0x384/0x540 block/blk-core.c:629
       __submit_bio_noacct_mq block/blk-core.c:710 [inline]
       submit_bio_noacct_nocheck+0x698/0xd70 block/blk-core.c:739
       submit_bio_noacct+0x93a/0x1e20 block/blk-core.c:868
       mpage_bio_submit_read fs/mpage.c:75 [inline]
       mpage_readahead+0x41d/0x590 fs/mpage.c:377
       read_pages+0x1a8/0xdc0 mm/readahead.c:160
       page_cache_ra_unbounded+0x3dc/0x750 mm/readahead.c:295
       do_page_cache_ra mm/readahead.c:325 [inline]
       force_page_cache_ra+0x24b/0x340 mm/readahead.c:354
       page_cache_sync_ra+0x110/0x9c0 mm/readahead.c:566
       page_cache_sync_readahead include/linux/pagemap.h:1397 [inline]
       filemap_get_pages+0xd7b/0x1be0 mm/filemap.c:2537
       filemap_read+0x3ca/0xd70 mm/filemap.c:2637
       blkdev_read_iter+0x187/0x480 block/fops.c:770
       new_sync_read fs/read_write.c:484 [inline]
       vfs_read+0x87f/0xbe0 fs/read_write.c:565
       ksys_read+0x12b/0x250 fs/read_write.c:708
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (mapping.invalidate_lock#2){++++}-{4:4}:
       down_read+0x9a/0x330 kernel/locking/rwsem.c:1524
       filemap_invalidate_lock_shared include/linux/fs.h:873 [inline]
       filemap_fault+0x2e0/0x2820 mm/filemap.c:3323
       __do_fault+0x10a/0x490 mm/memory.c:4907
       do_shared_fault mm/memory.c:5386 [inline]
       do_fault mm/memory.c:5460 [inline]
       do_pte_missing+0x1a8/0x3e00 mm/memory.c:3979
       handle_pte_fault mm/memory.c:5801 [inline]
       __handle_mm_fault+0x103c/0x2a40 mm/memory.c:5944
       handle_mm_fault+0x3fa/0xaa0 mm/memory.c:6112
       faultin_page mm/gup.c:1196 [inline]
       __get_user_pages+0x8d9/0x3b50 mm/gup.c:1494
       __get_user_pages_locked mm/gup.c:1760 [inline]
       faultin_page_range+0x24a/0x980 mm/gup.c:1984
       madvise_populate mm/madvise.c:951 [inline]
       do_madvise+0x504/0x770 mm/madvise.c:1681
       __do_sys_madvise mm/madvise.c:1700 [inline]
       __se_sys_madvise mm/madvise.c:1698 [inline]
       __x64_sys_madvise+0xa9/0x110 mm/madvise.c:1698
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (&mm->mmap_lock){++++}-{4:4}:
       __might_fault mm/memory.c:6751 [inline]
       __might_fault+0x11b/0x190 mm/memory.c:6744
       _inline_copy_from_user include/linux/uaccess.h:162 [inline]
       _copy_from_user+0x29/0xd0 lib/usercopy.c:18
       copy_from_user include/linux/uaccess.h:212 [inline]
       __blk_trace_setup+0xa8/0x180 kernel/trace/blktrace.c:626
       blk_trace_setup+0x47/0x70 kernel/trace/blktrace.c:648
       sg_ioctl_common drivers/scsi/sg.c:1114 [inline]
       sg_ioctl+0x65e/0x2750 drivers/scsi/sg.c:1156
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl fs/ioctl.c:892 [inline]
       __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&q->debugfs_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
       blk_mq_init_sched+0x42b/0x640 block/blk-mq-sched.c:473
       elevator_init_mq+0x2cd/0x420 block/elevator.c:610
       add_disk_fwnode+0x113/0x1300 block/genhd.c:413
       sd_probe+0xa86/0x1000 drivers/scsi/sd.c:4024
       call_driver_probe drivers/base/dd.c:579 [inline]
       really_probe+0x23e/0xa90 drivers/base/dd.c:658
       __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800
       driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830
       __device_attach_driver+0x1df/0x310 drivers/base/dd.c:958
       bus_for_each_drv+0x157/0x1e0 drivers/base/bus.c:459
       __device_attach_async_helper+0x1d3/0x290 drivers/base/dd.c:987
       async_run_entry_fn+0x9c/0x530 kernel/async.c:129
       process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
       process_scheduled_works kernel/workqueue.c:3310 [inline]
       worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
       kthread+0x2c1/0x3a0 kernel/kthread.c:389
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #1 (&q->q_usage_counter(queue)#50){++++}-{0:0}:
       blk_queue_enter+0x50f/0x640 block/blk-core.c:328
       blk_mq_alloc_request+0x59b/0x950 block/blk-mq.c:652
       scsi_alloc_request drivers/scsi/scsi_lib.c:1222 [inline]
       scsi_execute_cmd+0x1eb/0xf40 drivers/scsi/scsi_lib.c:304
       read_capacity_16+0x213/0xe10 drivers/scsi/sd.c:2655
       sd_read_capacity drivers/scsi/sd.c:2824 [inline]
       sd_revalidate_disk.isra.0+0x1a06/0xa8d0 drivers/scsi/sd.c:3734
       sd_probe+0x904/0x1000 drivers/scsi/sd.c:4010
       call_driver_probe drivers/base/dd.c:579 [inline]
       really_probe+0x23e/0xa90 drivers/base/dd.c:658
       __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800
       driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830
       __device_attach_driver+0x1df/0x310 drivers/base/dd.c:958
       bus_for_each_drv+0x157/0x1e0 drivers/base/bus.c:459
       __device_attach_async_helper+0x1d3/0x290 drivers/base/dd.c:987
       async_run_entry_fn+0x9c/0x530 kernel/async.c:129
       process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
       process_scheduled_works kernel/workqueue.c:3310 [inline]
       worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
       kthread+0x2c1/0x3a0 kernel/kthread.c:389
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (&q->limits_lock){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain kernel/locking/lockdep.c:3904 [inline]
       __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
       lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
       queue_limits_start_update include/linux/blkdev.h:947 [inline]
       __nbd_set_size+0x2c0/0x730 drivers/block/nbd.c:351
       nbd_set_size drivers/block/nbd.c:388 [inline]
       nbd_start_device+0x8fd/0xd70 drivers/block/nbd.c:1456
       nbd_genl_connect+0x1204/0x1c00 drivers/block/nbd.c:2139
       genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115
       genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
       genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210
       netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2542
       genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
       netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
       netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1347
       netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1891
       sock_sendmsg_nosec net/socket.c:711 [inline]
       __sock_sendmsg net/socket.c:726 [inline]
       ____sys_sendmsg+0xaaf/0xc90 net/socket.c:2583
       ___sys_sendmsg+0x135/0x1e0 net/socket.c:2637
       __sys_sendmsg+0x16e/0x220 net/socket.c:2669
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &q->limits_lock --> mapping.invalidate_lock#2 --> &q->q_usage_counter(io)#49

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&q->q_usage_counter(io)#49);
                               lock(mapping.invalidate_lock#2);
                               lock(&q->q_usage_counter(io)#49);
  lock(&q->limits_lock);

 *** DEADLOCK ***

5 locks held by syz.1.2094/15337:
 #0: ffffffff8ff7bf10 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
 #1: ffffffff8ff7bfc8 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline]
 #1: ffffffff8ff7bfc8 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline]
 #1: ffffffff8ff7bfc8 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:57 [inline]
 #1: ffffffff8ff7bfc8 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x580/0x800 net/netlink/genetlink.c:1209
 #2: ffff888026957998 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_genl_connect+0x433/0x1c00 drivers/block/nbd.c:2049
 #3: ffff8880262fd8b0 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: nbd_set_size drivers/block/nbd.c:387 [inline]
 #3: ffff8880262fd8b0 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: nbd_start_device+0x8ef/0xd70 drivers/block/nbd.c:1456
 #4: ffff8880262fd8e8 (&q->q_usage_counter(queue)#33){+.+.}-{0:0}, at: nbd_set_size drivers/block/nbd.c:387 [inline]
 #4: ffff8880262fd8e8 (&q->q_usage_counter(queue)#33){+.+.}-{0:0}, at: nbd_start_device+0x8ef/0xd70 drivers/block/nbd.c:1456

stack backtrace:
CPU: 0 UID: 0 PID: 15337 Comm: syz.1.2094 Not tainted 6.13.0-rc6-syzkaller-00059-g643e2e259c2b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x419/0x5d0 kernel/locking/lockdep.c:2074
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain kernel/locking/lockdep.c:3904 [inline]
 __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
 queue_limits_start_update include/linux/blkdev.h:947 [inline]
 __nbd_set_size+0x2c0/0x730 drivers/block/nbd.c:351
 nbd_set_size drivers/block/nbd.c:388 [inline]
 nbd_start_device+0x8fd/0xd70 drivers/block/nbd.c:1456
 nbd_genl_connect+0x1204/0x1c00 drivers/block/nbd.c:2139
 genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2542
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
 netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1347
 netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg net/socket.c:726 [inline]
 ____sys_sendmsg+0xaaf/0xc90 net/socket.c:2583
 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2637
 __sys_sendmsg+0x16e/0x220 net/socket.c:2669
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f73ae585d29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f73af3df038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f73ae775fa0 RCX: 00007f73ae585d29
RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 0000000000000007
RBP: 00007f73ae601b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f73ae775fa0 R15: 00007ffee2d258a8
 </TASK>