Hello, syzbot found the following issue on: HEAD commit: 06dc10eae55b Merge tag 'fbdev-for-6.6-rc7' of git://git.ke.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=13200f55680000 kernel config: https://syzkaller.appspot.com/x/.config?x=d236817624b4822c dashboard link: https://syzkaller.appspot.com/bug?extid=39a85bc0224f82336405 compiler: aarch64-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 userspace arch: arm64 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/384ffdcca292/non_bootable_disk-06dc10ea.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/84fbcc80ef2d/vmlinux-06dc10ea.xz kernel image: https://storage.googleapis.com/syzbot-assets/a061d48adac0/Image-06dc10ea.gz.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+39a85bc0224f82336405@xxxxxxxxxxxxxxxxxxxxxxxxx EEVDF scheduling fail, picking leftmost ====================================================== WARNING: possible circular locking dependency detected 6.6.0-rc6-syzkaller-00039-g06dc10eae55b #0 Not tainted ------------------------------------------------------ syz-executor.1/3112 is trying to acquire lock: ffff8000865271b8 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x18/0x80 kernel/locking/semaphore.c:139 but task is already holding lock: ffff00006a8dd758 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:558 [inline] ffff00006a8dd758 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock kernel/sched/sched.h:1372 [inline] ffff00006a8dd758 (&rq->__lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1681 [inline] ffff00006a8dd758 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x268/0x2ae4 kernel/sched/core.c:6612 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&rq->__lock){-.-.}-{2:2}: _raw_spin_lock_nested+0x50/0x6c kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x2c/0x44 kernel/sched/core.c:558 raw_spin_rq_lock kernel/sched/sched.h:1372 [inline] rq_lock kernel/sched/sched.h:1681 [inline] task_fork_fair+0x70/0x13c kernel/sched/fair.c:12416 sched_cgroup_fork+0x35c/0x520 kernel/sched/core.c:4816 copy_process+0x2fb0/0x5520 kernel/fork.c:2609 kernel_clone+0x140/0x7e8 kernel/fork.c:2909 user_mode_thread+0xb4/0xf0 kernel/fork.c:2987 rest_init+0x2c/0x210 init/main.c:691 arch_post_acpi_subsys_init+0x0/0x8 init/main.c:823 start_kernel+0x328/0x3a0 init/main.c:1068 __primary_switched+0xb8/0xc0 arch/arm64/kernel/head.S:523 -> #1 (&p->pi_lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x58/0x80 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:518 [inline] try_to_wake_up+0xac/0x1924 kernel/sched/core.c:4230 wake_up_process+0x18/0x24 kernel/sched/core.c:4478 __up.isra.0+0x124/0x18c kernel/locking/semaphore.c:278 up+0x94/0xd4 kernel/locking/semaphore.c:191 __up_console_sem kernel/printk/printk.c:346 [inline] __console_unlock kernel/printk/printk.c:2718 [inline] console_unlock+0x1b8/0x1d8 kernel/printk/printk.c:3037 fb_flashcursor drivers/video/fbdev/core/fbcon.c:382 [inline] fb_flashcursor+0x220/0x340 drivers/video/fbdev/core/fbcon.c:348 process_one_work+0x670/0x143c kernel/workqueue.c:2630 process_scheduled_works kernel/workqueue.c:2703 [inline] worker_thread+0x5a8/0xfb0 kernel/workqueue.c:2784 kthread+0x27c/0x300 kernel/kthread.c:388 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:857 -> #0 ((console_sem).lock){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x2cac/0x6b70 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x480/0x7c8 kernel/locking/lockdep.c:5718 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x58/0x80 kernel/locking/spinlock.c:162 down_trylock+0x18/0x80 kernel/locking/semaphore.c:139 __down_trylock_console_sem+0x38/0xd8 kernel/printk/printk.c:329 console_trylock kernel/printk/printk.c:2671 [inline] console_trylock_spinning kernel/printk/printk.c:1927 [inline] vprintk_emit+0x334/0x4e4 kernel/printk/printk.c:2306 vprintk_default+0x38/0x44 kernel/printk/printk.c:2322 vprintk+0x17c/0x1bc kernel/printk/printk_safe.c:45 _printk+0xa8/0xe0 kernel/printk/printk.c:2332 pick_eevdf kernel/sched/fair.c:976 [inline] pick_next_entity kernel/sched/fair.c:5278 [inline] pick_next_task_fair+0x1a4/0xd3c kernel/sched/fair.c:8222 __pick_next_task kernel/sched/core.c:6004 [inline] pick_next_task kernel/sched/core.c:6514 [inline] __schedule+0x3b8/0x2ae4 kernel/sched/core.c:6659 preempt_schedule_common kernel/sched/core.c:6864 [inline] preempt_schedule+0xf4/0x254 kernel/sched/core.c:6888 __mutex_lock_common kernel/locking/mutex.c:613 [inline] __mutex_lock+0x2b0/0x840 kernel/locking/mutex.c:747 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:799 xt_find_table_lock+0x68/0x418 net/netfilter/x_tables.c:1242 get_entries net/ipv6/netfilter/ip6_tables.c:1035 [inline] do_ip6t_get_ctl+0x340/0x980 net/ipv6/netfilter/ip6_tables.c:1669 nf_getsockopt+0x78/0xec net/netfilter/nf_sockopt.c:116 ipv6_getsockopt+0x210/0x34c net/ipv6/ipv6_sockglue.c:1500 tcp_getsockopt+0x7c/0x248 net/ipv4/tcp.c:4278 sock_common_getsockopt+0x70/0xc8 net/core/sock.c:3672 __sys_getsockopt+0x190/0x478 net/socket.c:2371 __do_sys_getsockopt net/socket.c:2386 [inline] __se_sys_getsockopt net/socket.c:2383 [inline] __arm64_sys_getsockopt+0xa4/0x100 net/socket.c:2383 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:51 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:136 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x58/0x140 arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595 other info that might help us debug this: Chain exists of: (console_sem).lock --> &p->pi_lock --> &rq->__lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&rq->__lock); lock(&p->pi_lock); lock(&rq->__lock); lock((console_sem).lock); *** DEADLOCK *** 2 locks held by syz-executor.1/3112: #0: ffff000013bfcd88 (&xt[i].mutex){+.+.}-{3:3}, at: xt_find_table_lock+0x68/0x418 net/netfilter/x_tables.c:1242 #1: ffff00006a8dd758 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:558 [inline] #1: ffff00006a8dd758 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock kernel/sched/sched.h:1372 [inline] #1: ffff00006a8dd758 (&rq->__lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1681 [inline] #1: ffff00006a8dd758 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x268/0x2ae4 kernel/sched/core.c:6612 stack backtrace: CPU: 0 PID: 3112 Comm: syz-executor.1 Not tainted 6.6.0-rc6-syzkaller-00039-g06dc10eae55b #0 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x9c/0x11c arch/arm64/kernel/stacktrace.c:233 show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:240 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x74/0xd4 lib/dump_stack.c:106 dump_stack+0x1c/0x28 lib/dump_stack.c:113 print_circular_bug+0x420/0x6f8 kernel/locking/lockdep.c:2060 check_noncircular+0x2dc/0x364 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x2cac/0x6b70 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x480/0x7c8 kernel/locking/lockdep.c:5718 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x58/0x80 kernel/locking/spinlock.c:162 down_trylock+0x18/0x80 kernel/locking/semaphore.c:139 __down_trylock_console_sem+0x38/0xd8 kernel/printk/printk.c:329 console_trylock kernel/printk/printk.c:2671 [inline] console_trylock_spinning kernel/printk/printk.c:1927 [inline] vprintk_emit+0x334/0x4e4 kernel/printk/printk.c:2306 vprintk_default+0x38/0x44 kernel/printk/printk.c:2322 vprintk+0x17c/0x1bc kernel/printk/printk_safe.c:45 _printk+0xa8/0xe0 kernel/printk/printk.c:2332 pick_eevdf kernel/sched/fair.c:976 [inline] pick_next_entity kernel/sched/fair.c:5278 [inline] pick_next_task_fair+0x1a4/0xd3c kernel/sched/fair.c:8222 __pick_next_task kernel/sched/core.c:6004 [inline] pick_next_task kernel/sched/core.c:6514 [inline] __schedule+0x3b8/0x2ae4 kernel/sched/core.c:6659 preempt_schedule_common kernel/sched/core.c:6864 [inline] preempt_schedule+0xf4/0x254 kernel/sched/core.c:6888 __mutex_lock_common kernel/locking/mutex.c:613 [inline] __mutex_lock+0x2b0/0x840 kernel/locking/mutex.c:747 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:799 xt_find_table_lock+0x68/0x418 net/netfilter/x_tables.c:1242 get_entries net/ipv6/netfilter/ip6_tables.c:1035 [inline] do_ip6t_get_ctl+0x340/0x980 net/ipv6/netfilter/ip6_tables.c:1669 nf_getsockopt+0x78/0xec net/netfilter/nf_sockopt.c:116 ipv6_getsockopt+0x210/0x34c net/ipv6/ipv6_sockglue.c:1500 tcp_getsockopt+0x7c/0x248 net/ipv4/tcp.c:4278 sock_common_getsockopt+0x70/0xc8 net/core/sock.c:3672 __sys_getsockopt+0x190/0x478 net/socket.c:2371 __do_sys_getsockopt net/socket.c:2386 [inline] __se_sys_getsockopt net/socket.c:2383 [inline] __arm64_sys_getsockopt+0xa4/0x100 net/socket.c:2383 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:51 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:136 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x58/0x140 arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the bug is already fixed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite bug's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the bug is a duplicate of another bug, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
