INFO: task syz.4.3499:22865 blocked for more than 143 seconds. Not tainted 6.11.0-rc7-syzkaller-00152-g68d4209158f4 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.3499 state:D stack:28392 pid:22865 tgid:22864 ppid:21156 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0xcda/0x2f80 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6621 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752 usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 usb_open+0x213/0x2f0 drivers/usb/core/file.c:47 chrdev_open+0x26d/0x6f0 fs/char_dev.c:414 do_dentry_open+0x957/0x1490 fs/open.c:959 vfs_open+0x82/0x3f0 fs/open.c:1089 do_open fs/namei.c:3727 [inline] path_openat+0x2141/0x2d20 fs/namei.c:3886 do_filp_open+0x1dc/0x430 fs/namei.c:3913 do_sys_openat2+0x17a/0x1e0 fs/open.c:1416 do_sys_open fs/open.c:1431 [inline] __do_sys_openat fs/open.c:1447 [inline] __se_sys_openat fs/open.c:1442 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1442 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: 0033:0x7f096834c890 RSP: 002b:00007f0966fc6b70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f096834c890 RDX: 0000000000000002 RSI: 00007f0966fc6c10 RDI: 00000000ffffff9c RBP: 00007f0966fc6c10 R08: 0000000000000000 R09: 00007f0966fc6987 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f0968505f80 R15: 00007ffe49d4e698 INFO: task syz.3.3500:22870 blocked for more than 143 seconds. Not tainted 6.11.0-rc7-syzkaller-00152-g68d4209158f4 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.3500 state:D stack:28464 pid:22870 tgid:22869 ppid:20770 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0xcda/0x2f80 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6621 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752 usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 usb_open+0x213/0x2f0 drivers/usb/core/file.c:47 chrdev_open+0x26d/0x6f0 fs/char_dev.c:414 do_dentry_open+0x957/0x1490 fs/open.c:959 vfs_open+0x82/0x3f0 fs/open.c:1089 do_open fs/namei.c:3727 [inline] path_openat+0x2141/0x2d20 fs/namei.c:3886 do_filp_open+0x1dc/0x430 fs/namei.c:3913 do_sys_openat2+0x17a/0x1e0 fs/open.c:1416 do_sys_open fs/open.c:1431 [inline] __do_sys_openat fs/open.c:1447 [inline] __se_sys_openat fs/open.c:1442 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1442 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: 0033:0x7fee26dbc890 RSP: 002b:00007fee25a36b70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fee26dbc890 RDX: 0000000000000002 RSI: 00007fee25a36c10 RDI: 00000000ffffff9c RBP: 00007fee25a36c10 R08: 0000000000000000 R09: 00007fee25a36987 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fee26f75f80 R15: 00007ffeb023e3a8 INFO: task syz.0.3506:22895 blocked for more than 144 seconds. Not tainted 6.11.0-rc7-syzkaller-00152-g68d4209158f4 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.3506 state:D stack:28896 pid:22895 tgid:22894 ppid:19730 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0xcda/0x2f80 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6621 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752 usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 usb_open+0x213/0x2f0 drivers/usb/core/file.c:47 chrdev_open+0x26d/0x6f0 fs/char_dev.c:414 do_dentry_open+0x957/0x1490 fs/open.c:959 vfs_open+0x82/0x3f0 fs/open.c:1089 do_open fs/namei.c:3727 [inline] path_openat+0x2141/0x2d20 fs/namei.c:3886 do_filp_open+0x1dc/0x430 fs/namei.c:3913 do_sys_openat2+0x17a/0x1e0 fs/open.c:1416 do_sys_open fs/open.c:1431 [inline] __do_sys_openat fs/open.c:1447 [inline] __se_sys_openat fs/open.c:1442 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1442 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: 0033:0x7fd37cdcc890 RSP: 002b:00007fd37ba46b70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fd37cdcc890 RDX: 0000000000000002 RSI: 00007fd37ba46c10 RDI: 00000000ffffff9c RBP: 00007fd37ba46c10 R08: 0000000000000000 R09: 00007fd37ba46987 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fd37cf85f80 R15: 00007ffd3d020b18 INFO: task syz.2.3516:23215 blocked for more than 144 seconds. Not tainted 6.11.0-rc7-syzkaller-00152-g68d4209158f4 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.3516 state:D stack:28864 pid:23215 tgid:23213 ppid:21893 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0xcda/0x2f80 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6621 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6678 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752 usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 usb_open+0x213/0x2f0 drivers/usb/core/file.c:47 chrdev_open+0x26d/0x6f0 fs/char_dev.c:414 do_dentry_open+0x957/0x1490 fs/open.c:959 vfs_open+0x82/0x3f0 fs/open.c:1089 do_open fs/namei.c:3727 [inline] path_openat+0x2141/0x2d20 fs/namei.c:3886 do_filp_open+0x1dc/0x430 fs/namei.c:3913 do_sys_openat2+0x17a/0x1e0 fs/open.c:1416 do_sys_open fs/open.c:1431 [inline] __do_sys_openat fs/open.c:1447 [inline] __se_sys_openat fs/open.c:1442 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1442 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: 0033:0x7f931dc7c890 RSP: 002b:00007f931c8f0b70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f931dc7c890 RDX: 0000000000000002 RSI: 00007f931c8f0c10 RDI: 00000000ffffff9c RBP: 00007f931c8f0c10 R08: 0000000000000000 R09: 00007f931c8f0987 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f931de35f80 R15: 00007ffed0a768a8 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff88ebb660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline] #0: ffffffff88ebb660 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff88ebb660 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6626 2 locks held by klogd/2536: 2 locks held by getty/2605: #0: ffff888108adf0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000432f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfc8/0x1490 drivers/tty/n_tty.c:2211 5 locks held by kworker/1:6/5167: #0: ffff888105ebad48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1277/0x1b40 kernel/workqueue.c:3206 #1: ffffc9000ef1fd80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x921/0x1b40 kernel/workqueue.c:3207 #2: ffff888109732190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1009 [inline] #2: ffff888109732190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1be/0x4f40 drivers/usb/core/hub.c:5849 #3: ffff888111bf1190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1009 [inline] #3: ffff888111bf1190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x10a/0x920 drivers/usb/core/hub.c:2295 #4: ffff888112f4f160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1009 [inline] #4: ffff888112f4f160 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1094 [inline] #4: ffff888112f4f160 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa4/0x610 drivers/base/dd.c:1292 1 lock held by syz.1.3493/22848: #0: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_release+0x7f/0x310 drivers/usb/class/usblp.c:480 2 locks held by syz.4.3499/22865: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.3.3500/22870: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.0.3506/22895: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.2.3516/23215: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 5 locks held by kworker/u8:5/23693: #0: ffff888100abb148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x1277/0x1b40 kernel/workqueue.c:3206 #1: ffffc9000200fd80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x921/0x1b40 kernel/workqueue.c:3207 #2: ffffffff8a161d50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xbb/0xbb0 net/core/net_namespace.c:594 #3: ffffffff8a1776e8 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0x8c/0xae0 net/core/dev.c:11883 #4: ffffffff88ec6df8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock+0x282/0x3b0 kernel/rcu/tree_exp.h:296 2 locks held by syz.4.3527/25075: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.3.3531/25175: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.2.3517/25279: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.2.3517/25280: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.0.3537/25285: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.4.3560/26879: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.2.3573/27205: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.0.3575/27212: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.0.3575/27213: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.0.3575/27214: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.0.3575/27222: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.3.3582/27247: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 2 locks held by syz.4.3581/28195: #0: ffffffff899b0110 (minor_rwsem){++++}-{3:3}, at: usb_open+0x27/0x2f0 drivers/usb/core/file.c:38 #1: ffffffff89a693e8 (usblp_mutex){+.+.}-{3:3}, at: usblp_open+0x5c/0x450 drivers/usb/class/usblp.c:417 1 lock held by syz.1.3603/29147: #0: ffffffff88ec6df8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock+0x1a4/0x3b0 kernel/rcu/tree_exp.h:328 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.11.0-rc7-syzkaller-00152-g68d4209158f4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline] watchdog+0xf0c/0x1240 kernel/hung_task.c:379 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 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 2529 Comm: syslogd Not tainted 6.11.0-rc7-syzkaller-00152-g68d4209158f4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 RIP: 0010:__skb_wait_for_more_packets+0x0/0x5e0 net/core/datagram.c:90 Code: 02 ff ff ff e8 f1 e0 db fb e9 3e ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 49 bf 00 00 00 00 00 fc ff df 41 56 41 55 41 54 RSP: 0018:ffffc9000159fa08 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 7fffffffffffffff RCX: ffffc9000159fad8 RDX: ffffc9000159fa98 RSI: ffff888114b7a8e8 RDI: ffff888114b7a800 RBP: ffff888114b7a800 R08: ffff888114b7a8e8 R09: 0000000000000000 R10: 7fffffffffffffff R11: 0000000000000000 R12: 0000000000000000 R13: ffffc9000159fa98 R14: ffff888114b7a8e8 R15: ffff888114b7ad10 FS: 00007fdc1e0da380(0000) GS:ffff8881f5900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f337c4291b0 CR3: 0000000115790000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __unix_dgram_recvmsg+0x243/0xdd0 net/unix/af_unix.c:2455 unix_dgram_recvmsg+0xd0/0x110 net/unix/af_unix.c:2544 sock_recvmsg_nosec net/socket.c:1046 [inline] sock_recvmsg+0x1f6/0x250 net/socket.c:1068 sock_read_iter+0x2c7/0x3c0 net/socket.c:1138 new_sync_read fs/read_write.c:395 [inline] vfs_read+0xa39/0xbd0 fs/read_write.c:476 ksys_read+0x1f8/0x260 fs/read_write.c:619 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: 0033:0x7fdc1e22eb6a Code: 00 3d 00 00 41 00 75 0d 50 48 8d 3d 2d 08 0a 00 e8 ea 7d 01 00 31 c0 e9 07 ff ff ff 64 8b 04 25 18 00 00 00 85 c0 75 1b 0f 05 <48> 3d 00 f0 ff ff 76 6c 48 8b 15 8f a2 0d 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffedf1d68e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fdc1e22eb6a RDX: 00000000000000ff RSI: 000055bf5e543300 RDI: 0000000000000000 RBP: 000055bf5e5432c0 R08: 0000000000000001 R09: 0000000000000000 R10: 00007fdc1e3cd3a3 R11: 0000000000000246 R12: 000055bf5e54334d R13: 000055bf5e543300 R14: 0000000000000000 R15: 00007fdc1e411a80