Hello, I found a potential bug titled " possible deadlock in perf_ctx_lock " with modified syzkaller in the Linux6.12.25(longterm maintenance, last updated on April 25, 2025) If you fix this issue, please add the following tag to the commit: Reported-by: Jianzhou Zhao luckd0g@163.com, xingwei lee xrivendell7@gmail.com The commit of the kernel is : ef4999852d307d38cfdecd91ed6892cc03beb9b8 kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=55f8591b98dd132 compiler: gcc version 11.4.0
Unfortunately, I am unable to reproduce this bug.
------------[ cut here ]----------------------------------------- TITLE: possible deadlock in perf_ctx_lock ------------[ cut here ]------------ ------------[ cut here ]------------ ====================================================== WARNING: possible circular locking dependency detected 6.12.25 #3 Not tainted ------------------------------------------------------ syz.9.499/15835 is trying to acquire lock: ffffffff8dec35a0 (console_owner){-.-.}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:2029 [inline] ffffffff8dec35a0 (console_owner){-.-.}-{0:0}, at: vprintk_emit kernel/printk/printk.c:2406 [inline] ffffffff8dec35a0 (console_owner){-.-.}-{0:0}, at: vprintk_emit+0x377/0x6d0 kernel/printk/printk.c:2353
but task is already holding lock: ffff88804ed2b818 (&ctx->lock){-...}-{2:2}, at: __perf_ctx_lock kernel/events/core.c:174 [inline] ffff88804ed2b818 (&ctx->lock){-...}-{2:2}, at: perf_ctx_lock+0x6a/0xe0 kernel/events/core.c:183
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&ctx->lock){-...}-{2:2}: __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 perf_event_context_sched_out kernel/events/core.c:3668 [inline] __perf_event_task_sched_out+0x4b3/0x18a0 kernel/events/core.c:3772 perf_event_task_sched_out include/linux/perf_event.h:1547 [inline] prepare_task_switch kernel/sched/core.c:5136 [inline] context_switch kernel/sched/core.c:5279 [inline] __schedule+0x2250/0x5b20 kernel/sched/core.c:6710 __schedule_loop kernel/sched/core.c:6787 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6802 futex_wait_queue+0x101/0x1f0 kernel/futex/waitwake.c:370 __futex_wait+0x23d/0x3c0 kernel/futex/waitwake.c:669 futex_wait+0xdc/0x370 kernel/futex/waitwake.c:697 do_futex+0x250/0x360 kernel/futex/syscalls.c:102 __do_sys_futex kernel/futex/syscalls.c:179 [inline] __se_sys_futex kernel/futex/syscalls.c:160 [inline] __x64_sys_futex+0x1c6/0x4c0 kernel/futex/syscalls.c:160 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcb/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (&rq->__lock){-.-.}-{2:2}: _raw_spin_lock_nested+0x34/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x2f/0x120 kernel/sched/core.c:598 raw_spin_rq_lock kernel/sched/sched.h:1515 [inline] task_rq_lock+0xd3/0x390 kernel/sched/core.c:700 cgroup_move_task+0x70/0x220 kernel/sched/psi.c:1161 css_set_move_task+0x280/0x570 kernel/cgroup/cgroup.c:898 cgroup_post_fork+0x20c/0x9d0 kernel/cgroup/cgroup.c:6705 copy_process+0x4bf6/0x8960 kernel/fork.c:2623 kernel_clone+0xeb/0x8f0 kernel/fork.c:2809 user_mode_thread+0xc9/0x110 kernel/fork.c:2887 rest_init+0x23/0x2b0 init/main.c:712 start_kernel+0x3dd/0x4c0 init/main.c:1105 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0xb3/0xc0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x148
-> #3 (&p->pi_lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline] try_to_wake_up+0xb1/0x14b0 kernel/sched/core.c:4168 autoremove_wake_function+0x16/0x150 kernel/sched/wait.c:384 __wake_up_common+0x135/0x1f0 kernel/sched/wait.c:89 __wake_up_common_lock kernel/sched/wait.c:106 [inline] __wake_up+0x31/0x60 kernel/sched/wait.c:127 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6a8/0x8a0 drivers/tty/serial/8250/8250_port.c:1821 serial8250_handle_irq+0x6a2/0xbb0 drivers/tty/serial/8250/8250_port.c:1929 serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1949 serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:86 __handle_irq_event_percpu+0x22a/0x7b0 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x265/0xd10 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:249 [inline] call_irq_handler arch/x86/kernel/irq.c:261 [inline] __common_interrupt+0xe0/0x250 arch/x86/kernel/irq.c:287 common_interrupt+0xf2/0x110 arch/x86/kernel/irq.c:280 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] pv_native_safe_halt+0x1e/0x30 arch/x86/kernel/paravirt.c:105 arch_safe_halt arch/x86/include/asm/paravirt.h:112 [inline] default_idle+0x1d/0x30 arch/x86/kernel/process.c:747 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x318/0x3c0 kernel/sched/idle.c:326 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:424 rest_init+0x16b/0x2b0 init/main.c:747 start_kernel+0x3dd/0x4c0 init/main.c:1105 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0xb3/0xc0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x148
-> #2 (&tty->write_wait){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 __wake_up_common_lock kernel/sched/wait.c:105 [inline] __wake_up+0x1c/0x60 kernel/sched/wait.c:127 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6a8/0x8a0 drivers/tty/serial/8250/8250_port.c:1821 serial8250_handle_irq+0x6a2/0xbb0 drivers/tty/serial/8250/8250_port.c:1929 serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1949 serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:86 __handle_irq_event_percpu+0x22a/0x7b0 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x265/0xd10 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:249 [inline] call_irq_handler arch/x86/kernel/irq.c:261 [inline] __common_interrupt+0xe0/0x250 arch/x86/kernel/irq.c:287 common_interrupt+0xf2/0x110 arch/x86/kernel/irq.c:280 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] pv_native_safe_halt+0x1e/0x30 arch/x86/kernel/paravirt.c:105 arch_safe_halt arch/x86/include/asm/paravirt.h:112 [inline] default_idle+0x1d/0x30 arch/x86/kernel/process.c:747 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x318/0x3c0 kernel/sched/idle.c:326 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:424 rest_init+0x16b/0x2b0 init/main.c:747 start_kernel+0x3dd/0x4c0 init/main.c:1105 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0xb3/0xc0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x148
-> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:711 [inline] serial8250_console_write+0xb3e/0x19b0 drivers/tty/serial/8250/8250_port.c:3381 console_emit_next_record kernel/printk/printk.c:3090 [inline] console_flush_all+0x767/0xc30 kernel/printk/printk.c:3178 __console_flush_and_unlock kernel/printk/printk.c:3237 [inline] console_unlock+0xc3/0x1f0 kernel/printk/printk.c:3277 vprintk_emit kernel/printk/printk.c:2407 [inline] vprintk_emit+0x4fb/0x6d0 kernel/printk/printk.c:2353 vprintk+0x93/0xb0 kernel/printk/printk_safe.c:73 _printk+0xbf/0x100 kernel/printk/printk.c:2432 register_console+0xc11/0x11b0 kernel/printk/printk.c:4067 univ8250_console_init+0x62/0x90 drivers/tty/serial/8250/8250_core.c:513 console_init+0xcc/0x680 kernel/printk/printk.c:4260 start_kernel+0x293/0x4c0 init/main.c:1040 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0xb3/0xc0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x148
-> #0 (console_owner){-.-.}-{0:0}: 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+0x2425/0x3b90 kernel/locking/lockdep.c:5202 lock_acquire.part.0+0x11b/0x370 kernel/locking/lockdep.c:5825 console_trylock_spinning kernel/printk/printk.c:2029 [inline] vprintk_emit kernel/printk/printk.c:2406 [inline] vprintk_emit+0x38c/0x6d0 kernel/printk/printk.c:2353 vprintk+0x93/0xb0 kernel/printk/printk_safe.c:73 _printk+0xbf/0x100 kernel/printk/printk.c:2432 __report_bug lib/bug.c:195 [inline] report_bug+0x27c/0x500 lib/bug.c:219 handle_bug+0xe5/0x180 arch/x86/kernel/traps.c:285 exc_invalid_op+0x35/0x80 arch/x86/kernel/traps.c:309 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621 perf_trace_add+0x2da/0x390 kernel/trace/trace_event_perf.c:375 event_sched_in+0x434/0xac0 kernel/events/core.c:2629 group_sched_in kernel/events/core.c:2662 [inline] merge_sched_in+0x895/0x1570 kernel/events/core.c:3940 visit_groups_merge.constprop.0.isra.0+0x6d2/0x1250 kernel/events/core.c:3885 pmu_groups_sched_in kernel/events/core.c:3967 [inline] __pmu_ctx_sched_in kernel/events/core.c:3979 [inline] ctx_sched_in+0x5c1/0xa30 kernel/events/core.c:4030 perf_event_sched_in+0x5d/0x90 kernel/events/core.c:2760 perf_event_context_sched_in kernel/events/core.c:4077 [inline] __perf_event_task_sched_in+0x33a/0x6f0 kernel/events/core.c:4106 perf_event_task_sched_in include/linux/perf_event.h:1524 [inline] finish_task_switch.isra.0+0x5f9/0xcb0 kernel/sched/core.c:5201 context_switch kernel/sched/core.c:5335 [inline] __schedule+0x1156/0x5b20 kernel/sched/core.c:6710 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7032 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 __sanitizer_cov_trace_pc+0x0/0x80 kernel/kcov.c:127 rcu_read_unlock include/linux/rcupdate.h:878 [inline] count_memcg_events_mm.constprop.0+0x12a/0x330 include/linux/memcontrol.h:1046 count_memcg_event_mm include/linux/memcontrol.h:1052 [inline] mm_account_fault mm/memory.c:5947 [inline] handle_mm_fault+0x5af/0xab0 mm/memory.c:6107 do_user_addr_fault+0x61b/0x13a0 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x98/0x180 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
other info that might help us debug this:
Chain exists of: console_owner --> &rq->__lock --> &ctx->lock
Possible unsafe locking scenario:
CPU0 CPU1 ---- ---- lock(&ctx->lock); lock(&rq->__lock); lock(&ctx->lock); lock(console_owner);
*** DEADLOCK ***
5 locks held by syz.9.499/15835: #0: ffff88804a983b68 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:704 [inline] #0: ffff88804a983b68 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x141/0x9a0 mm/memory.c:6247 #1: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #1: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: count_memcg_events_mm.constprop.0+0x3a/0x330 include/linux/memcontrol.h:1042 #2: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #2: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #2: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: perf_event_context_sched_in kernel/events/core.c:4039 [inline] #2: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: __perf_event_task_sched_in+0xd3/0x6f0 kernel/events/core.c:4106 #3: ffff88802b837af8 (&cpuctx_lock){-.-.}-{2:2}, at: __perf_ctx_lock kernel/events/core.c:174 [inline] #3: ffff88802b837af8 (&cpuctx_lock){-.-.}-{2:2}, at: perf_ctx_lock+0x15/0xe0 kernel/events/core.c:181 #4: ffff88804ed2b818 (&ctx->lock){-...}-{2:2}, at: __perf_ctx_lock kernel/events/core.c:174 [inline] #4: ffff88804ed2b818 (&ctx->lock){-...}-{2:2}, at: perf_ctx_lock+0x6a/0xe0 kernel/events/core.c:183
stack backtrace: CPU: 0 UID: 0 PID: 15835 Comm: syz.9.499 Not tainted 6.12.25 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120 print_circular_bug+0x406/0x5c0 kernel/locking/lockdep.c:2074 check_noncircular+0x2f7/0x3e0 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+0x2425/0x3b90 kernel/locking/lockdep.c:5202 lock_acquire.part.0+0x11b/0x370 kernel/locking/lockdep.c:5825 console_trylock_spinning kernel/printk/printk.c:2029 [inline] vprintk_emit kernel/printk/printk.c:2406 [inline] vprintk_emit+0x38c/0x6d0 kernel/printk/printk.c:2353 vprintk+0x93/0xb0 kernel/printk/printk_safe.c:73 _printk+0xbf/0x100 kernel/printk/printk.c:2432 __report_bug lib/bug.c:195 [inline] report_bug+0x27c/0x500 lib/bug.c:219 handle_bug+0xe5/0x180 arch/x86/kernel/traps.c:285 exc_invalid_op+0x35/0x80 arch/x86/kernel/traps.c:309 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621 RIP: 0010:perf_trace_add+0x2da/0x390 kernel/trace/trace_event_perf.c:375 Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 64 48 89 ab f8 01 00 00 48 89 df e8 b1 ab 26 00 e9 f3 fd ff ff e8 37 87 f6 ff 90 <0f> 0b 90 41 bc ea ff ff ff e9 77 ff ff ff e8 23 c5 56 00 e9 8a fd RSP: 0018:ffffc9000713f7f0 EFLAGS: 00010006 RAX: 0000000040000002 RBX: ffff88802a069880 RCX: ffffffff8195a68e RDX: ffff888045ec2500 RSI: ffffffff8195a839 RDI: ffffffff8deabf48 RBP: 0000000000000000 R08: 0000000000000001 R09: fffff52000e27eef R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8deabee0 R14: ffff88802a069928 R15: ffff888051237200 event_sched_in+0x434/0xac0 kernel/events/core.c:2629 group_sched_in kernel/events/core.c:2662 [inline] merge_sched_in+0x895/0x1570 kernel/events/core.c:3940 visit_groups_merge.constprop.0.isra.0+0x6d2/0x1250 kernel/events/core.c:3885 pmu_groups_sched_in kernel/events/core.c:3967 [inline] __pmu_ctx_sched_in kernel/events/core.c:3979 [inline] ctx_sched_in+0x5c1/0xa30 kernel/events/core.c:4030 perf_event_sched_in+0x5d/0x90 kernel/events/core.c:2760 perf_event_context_sched_in kernel/events/core.c:4077 [inline] __perf_event_task_sched_in+0x33a/0x6f0 kernel/events/core.c:4106 perf_event_task_sched_in include/linux/perf_event.h:1524 [inline] finish_task_switch.isra.0+0x5f9/0xcb0 kernel/sched/core.c:5201 context_switch kernel/sched/core.c:5335 [inline] __schedule+0x1156/0x5b20 kernel/sched/core.c:6710 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7032 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x80 kernel/kcov.c:210 Code: 5d 41 5c 41 5d c3 cc cc cc cc 48 c7 c0 f4 ff ff ff eb 92 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 65 48 8b 15 04 ae 77 7e 65 8b 05 05 ae 77 7e a9 00 01 RSP: 0000:ffffc9000713fe20 EFLAGS: 00000212 RAX: 000000000000fe4d RBX: 0000000000000200 RCX: ffffc9002f801000 RDX: 0000000000080000 RSI: ffffffff81d2e884 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000001 R09: fffffbfff2d84fa6 R10: 0000000000000200 R11: 0000000000000000 R12: ffff888020dea000 R13: ffff88804a8558c8 R14: 0000000000000040 R15: ffff88804f13f200 rcu_read_unlock include/linux/rcupdate.h:878 [inline] count_memcg_events_mm.constprop.0+0x12a/0x330 include/linux/memcontrol.h:1046 count_memcg_event_mm include/linux/memcontrol.h:1052 [inline] mm_account_fault mm/memory.c:5947 [inline] handle_mm_fault+0x5af/0xab0 mm/memory.c:6107 do_user_addr_fault+0x61b/0x13a0 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x98/0x180 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7fe4fdc4f757 Code: 70 48 63 d5 48 01 c2 49 3b 55 08 77 4e 8d 55 ff 85 ed 74 35 0f 1f 80 00 00 00 00 48 39 c6 77 1c 49 8b 7d 00 49 89 c1 49 29 f1 <46> 0f b6 0c 0f 45 84 c9 74 08 44 88 0c 07 49 8b 45 10 48 83 c0 01 RSP: 002b:00007fe4fec1b420 EFLAGS: 00010206 RAX: 0000000000067001 RBX: 00007fe4fec1b480 RCX: 0000000000000000 RDX: 000000000000004c RSI: 0000000000000001 RDI: 00007fe4f3600000 RBP: 0000000000000102 R08: 0000000000000001 R09: 0000000000067000 R10: 0000000000000000 R11: 00007fe4fec1b490 R12: 00007fe4fec1b490 R13: 00007fe4fec1b520 R14: 0000000000000001 R15: 0000000000000000 </TASK> WARNING: CPU: 0 PID: 15835 at kernel/trace/trace_event_perf.c:375 perf_trace_add+0x2da/0x390 kernel/trace/trace_event_perf.c:375 Modules linked in: CPU: 0 UID: 0 PID: 15835 Comm: syz.9.499 Not tainted 6.12.25 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:perf_trace_add+0x2da/0x390 kernel/trace/trace_event_perf.c:375 Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 64 48 89 ab f8 01 00 00 48 89 df e8 b1 ab 26 00 e9 f3 fd ff ff e8 37 87 f6 ff 90 <0f> 0b 90 41 bc ea ff ff ff e9 77 ff ff ff e8 23 c5 56 00 e9 8a fd RSP: 0018:ffffc9000713f7f0 EFLAGS: 00010006 RAX: 0000000040000002 RBX: ffff88802a069880 RCX: ffffffff8195a68e RDX: ffff888045ec2500 RSI: ffffffff8195a839 RDI: ffffffff8deabf48 RBP: 0000000000000000 R08: 0000000000000001 R09: fffff52000e27eef R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8deabee0 R14: ffff88802a069928 R15: ffff888051237200 FS: 00007fe4fec1c640(0000) GS:ffff88802b800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f50219e7bac CR3: 00000000743bc000 CR4: 0000000000752ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 80000000 Call Trace: <TASK> event_sched_in+0x434/0xac0 kernel/events/core.c:2629 group_sched_in kernel/events/core.c:2662 [inline] merge_sched_in+0x895/0x1570 kernel/events/core.c:3940 visit_groups_merge.constprop.0.isra.0+0x6d2/0x1250 kernel/events/core.c:3885 pmu_groups_sched_in kernel/events/core.c:3967 [inline] __pmu_ctx_sched_in kernel/events/core.c:3979 [inline] ctx_sched_in+0x5c1/0xa30 kernel/events/core.c:4030 perf_event_sched_in+0x5d/0x90 kernel/events/core.c:2760 perf_event_context_sched_in kernel/events/core.c:4077 [inline] __perf_event_task_sched_in+0x33a/0x6f0 kernel/events/core.c:4106 perf_event_task_sched_in include/linux/perf_event.h:1524 [inline] finish_task_switch.isra.0+0x5f9/0xcb0 kernel/sched/core.c:5201 context_switch kernel/sched/core.c:5335 [inline] __schedule+0x1156/0x5b20 kernel/sched/core.c:6710 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7032 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x80 kernel/kcov.c:210 Code: 5d 41 5c 41 5d c3 cc cc cc cc 48 c7 c0 f4 ff ff ff eb 92 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 65 48 8b 15 04 ae 77 7e 65 8b 05 05 ae 77 7e a9 00 01 RSP: 0000:ffffc9000713fe20 EFLAGS: 00000212 RAX: 000000000000fe4d RBX: 0000000000000200 RCX: ffffc9002f801000 RDX: 0000000000080000 RSI: ffffffff81d2e884 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000001 R09: fffffbfff2d84fa6 R10: 0000000000000200 R11: 0000000000000000 R12: ffff888020dea000 R13: ffff88804a8558c8 R14: 0000000000000040 R15: ffff88804f13f200 rcu_read_unlock include/linux/rcupdate.h:878 [inline] count_memcg_events_mm.constprop.0+0x12a/0x330 include/linux/memcontrol.h:1046 count_memcg_event_mm include/linux/memcontrol.h:1052 [inline] mm_account_fault mm/memory.c:5947 [inline] handle_mm_fault+0x5af/0xab0 mm/memory.c:6107 do_user_addr_fault+0x61b/0x13a0 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x98/0x180 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7fe4fdc4f757 Code: 70 48 63 d5 48 01 c2 49 3b 55 08 77 4e 8d 55 ff 85 ed 74 35 0f 1f 80 00 00 00 00 48 39 c6 77 1c 49 8b 7d 00 49 89 c1 49 29 f1 <46> 0f b6 0c 0f 45 84 c9 74 08 44 88 0c 07 49 8b 45 10 48 83 c0 01 RSP: 002b:00007fe4fec1b420 EFLAGS: 00010206 RAX: 0000000000067001 RBX: 00007fe4fec1b480 RCX: 0000000000000000 RDX: 000000000000004c RSI: 0000000000000001 RDI: 00007fe4f3600000 RBP: 0000000000000102 R08: 0000000000000001 R09: 0000000000067000 R10: 0000000000000000 R11: 00007fe4fec1b490 R12: 00007fe4fec1b490 R13: 00007fe4fec1b520 R14: 0000000000000001 R15: 0000000000000000 </TASK> ---------------- Code disassembly (best guess): 0: 5d pop %rbp 1: 41 5c pop %r12 3: 41 5d pop %r13 5: c3 ret 6: cc int3 7: cc int3 8: cc int3 9: cc int3 a: 48 c7 c0 f4 ff ff ff mov $0xfffffffffffffff4,%rax 11: eb 92 jmp 0xffffffa5 13: 0f 1f 80 00 00 00 00 nopl 0x0(%rax) 1a: 90 nop 1b: 90 nop 1c: 90 nop 1d: 90 nop 1e: 90 nop 1f: 90 nop 20: 90 nop 21: 90 nop 22: 90 nop 23: 90 nop 24: 90 nop 25: 90 nop 26: 90 nop 27: 90 nop 28: 90 nop 29: 90 nop * 2a: f3 0f 1e fa endbr64 <-- trapping instruction 2e: 65 48 8b 15 04 ae 77 mov %gs:0x7e77ae04(%rip),%rdx # 0x7e77ae3a 35: 7e 36: 65 8b 05 05 ae 77 7e mov %gs:0x7e77ae05(%rip),%eax # 0x7e77ae42 3d: a9 .byte 0xa9 3e: 00 01 add %al,(%rcx) ===================================================================
I hope it helps. Best regards Jianzhou Zhao
When I attempted to reproduce the bug using the crashed log with the help of syzkaller, the following reproduction program was generated. Hope this is helpful to you.
#define _GNU_SOURCE
#include <endian.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/syscall.h> #include <sys/types.h> #include <unistd.h>
#define BITMASK(bf_off, bf_len) (((1ull << (bf_len)) - 1) << (bf_off)) #define STORE_BY_BITMASK(type, htobe, addr, val, bf_off, bf_len) \ *(type*)(addr) = \ htobe((htobe(*(type*)(addr)) & ~BITMASK((bf_off), (bf_len))) | \ (((type)(val) << (bf_off)) & BITMASK((bf_off), (bf_len))))
int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffffffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x200000000000ul, /*len=*/0x1000000ul, /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x200001000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); const char* reason; (void)reason; if (write(1, "executing program\n", sizeof("executing program\n") - 1)) { } *(uint32_t*)0x200000000000 = 2; *(uint32_t*)0x200000000004 = 0x80; *(uint8_t*)0x200000000008 = 0xef; *(uint8_t*)0x200000000009 = 0; *(uint8_t*)0x20000000000a = 0; *(uint8_t*)0x20000000000b = 0; *(uint32_t*)0x20000000000c = 0; *(uint64_t*)0x200000000010 = 0; *(uint64_t*)0x200000000018 = 0; *(uint64_t*)0x200000000020 = 0; STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 0, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 1, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 2, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 3, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 4, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 5, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 6, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 7, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 8, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 9, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 10, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 11, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 12, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 13, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 14, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 15, 2); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 17, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 18, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 19, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 20, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 21, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 22, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 23, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 24, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 25, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 26, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 27, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 28, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 29, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 30, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 31, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 32, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 33, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 34, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 35, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 36, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 37, 1); STORE_BY_BITMASK(uint64_t, , 0x200000000028, 0, 38, 26); *(uint32_t*)0x200000000030 = 0; *(uint32_t*)0x200000000034 = 0; *(uint64_t*)0x200000000038 = 0; *(uint64_t*)0x200000000040 = 0; *(uint64_t*)0x200000000048 = 0x6000; *(uint64_t*)0x200000000050 = 0xfffffffffffffffd; *(uint32_t*)0x200000000058 = 0; *(uint32_t*)0x20000000005c = 0; *(uint64_t*)0x200000000060 = 0; *(uint32_t*)0x200000000068 = 0; *(uint16_t*)0x20000000006c = 0x10; *(uint16_t*)0x20000000006e = 0; *(uint32_t*)0x200000000070 = 0; *(uint32_t*)0x200000000074 = 0; *(uint64_t*)0x200000000078 = 0; syscall(__NR_perf_event_open, /*attr=*/0x200000000000ul, /*pid=*/0, /*cpu=*/0ul, /*group=*/(intptr_t)-1, /*flags=*/0ul); return 0; }
At 2025-04-29 22:18:04, "Jianzhou Zhao" luckd0g@163.com wrote:
Hello, I found a potential bug titled " possible deadlock in perf_ctx_lock " with modified syzkaller in the Linux6.12.25(longterm maintenance, last updated on April 25, 2025) If you fix this issue, please add the following tag to the commit: Reported-by: Jianzhou Zhao luckd0g@163.com, xingwei lee xrivendell7@gmail.com The commit of the kernel is : ef4999852d307d38cfdecd91ed6892cc03beb9b8 kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=55f8591b98dd132 compiler: gcc version 11.4.0
Unfortunately, I am unable to reproduce this bug.
------------[ cut here ]----------------------------------------- TITLE: possible deadlock in perf_ctx_lock ------------[ cut here ]------------
------------[ cut here ]------------
WARNING: possible circular locking dependency detected 6.12.25 #3 Not tainted
syz.9.499/15835 is trying to acquire lock: ffffffff8dec35a0 (console_owner){-.-.}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:2029 [inline] ffffffff8dec35a0 (console_owner){-.-.}-{0:0}, at: vprintk_emit kernel/printk/printk.c:2406 [inline] ffffffff8dec35a0 (console_owner){-.-.}-{0:0}, at: vprintk_emit+0x377/0x6d0 kernel/printk/printk.c:2353
but task is already holding lock: ffff88804ed2b818 (&ctx->lock){-...}-{2:2}, at: __perf_ctx_lock kernel/events/core.c:174 [inline] ffff88804ed2b818 (&ctx->lock){-...}-{2:2}, at: perf_ctx_lock+0x6a/0xe0 kernel/events/core.c:183
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #5 (&ctx->lock){-...}-{2:2}: __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 perf_event_context_sched_out kernel/events/core.c:3668 [inline] __perf_event_task_sched_out+0x4b3/0x18a0 kernel/events/core.c:3772 perf_event_task_sched_out include/linux/perf_event.h:1547 [inline] prepare_task_switch kernel/sched/core.c:5136 [inline] context_switch kernel/sched/core.c:5279 [inline] __schedule+0x2250/0x5b20 kernel/sched/core.c:6710 __schedule_loop kernel/sched/core.c:6787 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6802 futex_wait_queue+0x101/0x1f0 kernel/futex/waitwake.c:370 __futex_wait+0x23d/0x3c0 kernel/futex/waitwake.c:669 futex_wait+0xdc/0x370 kernel/futex/waitwake.c:697 do_futex+0x250/0x360 kernel/futex/syscalls.c:102 __do_sys_futex kernel/futex/syscalls.c:179 [inline] __se_sys_futex kernel/futex/syscalls.c:160 [inline] __x64_sys_futex+0x1c6/0x4c0 kernel/futex/syscalls.c:160 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcb/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (&rq->__lock){-.-.}-{2:2}: _raw_spin_lock_nested+0x34/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x2f/0x120 kernel/sched/core.c:598 raw_spin_rq_lock kernel/sched/sched.h:1515 [inline] task_rq_lock+0xd3/0x390 kernel/sched/core.c:700 cgroup_move_task+0x70/0x220 kernel/sched/psi.c:1161 css_set_move_task+0x280/0x570 kernel/cgroup/cgroup.c:898 cgroup_post_fork+0x20c/0x9d0 kernel/cgroup/cgroup.c:6705 copy_process+0x4bf6/0x8960 kernel/fork.c:2623 kernel_clone+0xeb/0x8f0 kernel/fork.c:2809 user_mode_thread+0xc9/0x110 kernel/fork.c:2887 rest_init+0x23/0x2b0 init/main.c:712 start_kernel+0x3dd/0x4c0 init/main.c:1105 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0xb3/0xc0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x148
-> #3 (&p->pi_lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline] try_to_wake_up+0xb1/0x14b0 kernel/sched/core.c:4168 autoremove_wake_function+0x16/0x150 kernel/sched/wait.c:384 __wake_up_common+0x135/0x1f0 kernel/sched/wait.c:89 __wake_up_common_lock kernel/sched/wait.c:106 [inline] __wake_up+0x31/0x60 kernel/sched/wait.c:127 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6a8/0x8a0 drivers/tty/serial/8250/8250_port.c:1821 serial8250_handle_irq+0x6a2/0xbb0 drivers/tty/serial/8250/8250_port.c:1929 serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1949 serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:86 __handle_irq_event_percpu+0x22a/0x7b0 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x265/0xd10 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:249 [inline] call_irq_handler arch/x86/kernel/irq.c:261 [inline] __common_interrupt+0xe0/0x250 arch/x86/kernel/irq.c:287 common_interrupt+0xf2/0x110 arch/x86/kernel/irq.c:280 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] pv_native_safe_halt+0x1e/0x30 arch/x86/kernel/paravirt.c:105 arch_safe_halt arch/x86/include/asm/paravirt.h:112 [inline] default_idle+0x1d/0x30 arch/x86/kernel/process.c:747 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x318/0x3c0 kernel/sched/idle.c:326 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:424 rest_init+0x16b/0x2b0 init/main.c:747 start_kernel+0x3dd/0x4c0 init/main.c:1105 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0xb3/0xc0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x148
-> #2 (&tty->write_wait){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 __wake_up_common_lock kernel/sched/wait.c:105 [inline] __wake_up+0x1c/0x60 kernel/sched/wait.c:127 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6a8/0x8a0 drivers/tty/serial/8250/8250_port.c:1821 serial8250_handle_irq+0x6a2/0xbb0 drivers/tty/serial/8250/8250_port.c:1929 serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1949 serial8250_interrupt+0x103/0x210 drivers/tty/serial/8250/8250_core.c:86 __handle_irq_event_percpu+0x22a/0x7b0 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x265/0xd10 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline] handle_irq arch/x86/kernel/irq.c:249 [inline] call_irq_handler arch/x86/kernel/irq.c:261 [inline] __common_interrupt+0xe0/0x250 arch/x86/kernel/irq.c:287 common_interrupt+0xf2/0x110 arch/x86/kernel/irq.c:280 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] pv_native_safe_halt+0x1e/0x30 arch/x86/kernel/paravirt.c:105 arch_safe_halt arch/x86/include/asm/paravirt.h:112 [inline] default_idle+0x1d/0x30 arch/x86/kernel/process.c:747 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x318/0x3c0 kernel/sched/idle.c:326 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:424 rest_init+0x16b/0x2b0 init/main.c:747 start_kernel+0x3dd/0x4c0 init/main.c:1105 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0xb3/0xc0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x148
-> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:711 [inline] serial8250_console_write+0xb3e/0x19b0 drivers/tty/serial/8250/8250_port.c:3381 console_emit_next_record kernel/printk/printk.c:3090 [inline] console_flush_all+0x767/0xc30 kernel/printk/printk.c:3178 __console_flush_and_unlock kernel/printk/printk.c:3237 [inline] console_unlock+0xc3/0x1f0 kernel/printk/printk.c:3277 vprintk_emit kernel/printk/printk.c:2407 [inline] vprintk_emit+0x4fb/0x6d0 kernel/printk/printk.c:2353 vprintk+0x93/0xb0 kernel/printk/printk_safe.c:73 _printk+0xbf/0x100 kernel/printk/printk.c:2432 register_console+0xc11/0x11b0 kernel/printk/printk.c:4067 univ8250_console_init+0x62/0x90 drivers/tty/serial/8250/8250_core.c:513 console_init+0xcc/0x680 kernel/printk/printk.c:4260 start_kernel+0x293/0x4c0 init/main.c:1040 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0xb3/0xc0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x148
-> #0 (console_owner){-.-.}-{0:0}: 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+0x2425/0x3b90 kernel/locking/lockdep.c:5202 lock_acquire.part.0+0x11b/0x370 kernel/locking/lockdep.c:5825 console_trylock_spinning kernel/printk/printk.c:2029 [inline] vprintk_emit kernel/printk/printk.c:2406 [inline] vprintk_emit+0x38c/0x6d0 kernel/printk/printk.c:2353 vprintk+0x93/0xb0 kernel/printk/printk_safe.c:73 _printk+0xbf/0x100 kernel/printk/printk.c:2432 __report_bug lib/bug.c:195 [inline] report_bug+0x27c/0x500 lib/bug.c:219 handle_bug+0xe5/0x180 arch/x86/kernel/traps.c:285 exc_invalid_op+0x35/0x80 arch/x86/kernel/traps.c:309 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621 perf_trace_add+0x2da/0x390 kernel/trace/trace_event_perf.c:375 event_sched_in+0x434/0xac0 kernel/events/core.c:2629 group_sched_in kernel/events/core.c:2662 [inline] merge_sched_in+0x895/0x1570 kernel/events/core.c:3940 visit_groups_merge.constprop.0.isra.0+0x6d2/0x1250 kernel/events/core.c:3885 pmu_groups_sched_in kernel/events/core.c:3967 [inline] __pmu_ctx_sched_in kernel/events/core.c:3979 [inline] ctx_sched_in+0x5c1/0xa30 kernel/events/core.c:4030 perf_event_sched_in+0x5d/0x90 kernel/events/core.c:2760 perf_event_context_sched_in kernel/events/core.c:4077 [inline] __perf_event_task_sched_in+0x33a/0x6f0 kernel/events/core.c:4106 perf_event_task_sched_in include/linux/perf_event.h:1524 [inline] finish_task_switch.isra.0+0x5f9/0xcb0 kernel/sched/core.c:5201 context_switch kernel/sched/core.c:5335 [inline] __schedule+0x1156/0x5b20 kernel/sched/core.c:6710 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7032 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 __sanitizer_cov_trace_pc+0x0/0x80 kernel/kcov.c:127 rcu_read_unlock include/linux/rcupdate.h:878 [inline] count_memcg_events_mm.constprop.0+0x12a/0x330 include/linux/memcontrol.h:1046 count_memcg_event_mm include/linux/memcontrol.h:1052 [inline] mm_account_fault mm/memory.c:5947 [inline] handle_mm_fault+0x5af/0xab0 mm/memory.c:6107 do_user_addr_fault+0x61b/0x13a0 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x98/0x180 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
other info that might help us debug this:
Chain exists of: console_owner --> &rq->__lock --> &ctx->lock
Possible unsafe locking scenario:
CPU0 CPU1 ---- ----lock(&ctx->lock); lock(&rq->__lock); lock(&ctx->lock); lock(console_owner);
*** DEADLOCK ***
5 locks held by syz.9.499/15835: #0: ffff88804a983b68 (&vma->vm_lock->lock){++++}-{3:3}, at: vma_start_read include/linux/mm.h:704 [inline] #0: ffff88804a983b68 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x141/0x9a0 mm/memory.c:6247 #1: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #1: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: count_memcg_events_mm.constprop.0+0x3a/0x330 include/linux/memcontrol.h:1042 #2: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #2: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #2: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: perf_event_context_sched_in kernel/events/core.c:4039 [inline] #2: ffffffff8dfb62a0 (rcu_read_lock){....}-{1:2}, at: __perf_event_task_sched_in+0xd3/0x6f0 kernel/events/core.c:4106 #3: ffff88802b837af8 (&cpuctx_lock){-.-.}-{2:2}, at: __perf_ctx_lock kernel/events/core.c:174 [inline] #3: ffff88802b837af8 (&cpuctx_lock){-.-.}-{2:2}, at: perf_ctx_lock+0x15/0xe0 kernel/events/core.c:181 #4: ffff88804ed2b818 (&ctx->lock){-...}-{2:2}, at: __perf_ctx_lock kernel/events/core.c:174 [inline] #4: ffff88804ed2b818 (&ctx->lock){-...}-{2:2}, at: perf_ctx_lock+0x6a/0xe0 kernel/events/core.c:183
stack backtrace: CPU: 0 UID: 0 PID: 15835 Comm: syz.9.499 Not tainted 6.12.25 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace:
<TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120 print_circular_bug+0x406/0x5c0 kernel/locking/lockdep.c:2074 check_noncircular+0x2f7/0x3e0 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+0x2425/0x3b90 kernel/locking/lockdep.c:5202 lock_acquire.part.0+0x11b/0x370 kernel/locking/lockdep.c:5825 console_trylock_spinning kernel/printk/printk.c:2029 [inline] vprintk_emit kernel/printk/printk.c:2406 [inline] vprintk_emit+0x38c/0x6d0 kernel/printk/printk.c:2353 vprintk+0x93/0xb0 kernel/printk/printk_safe.c:73 _printk+0xbf/0x100 kernel/printk/printk.c:2432 __report_bug lib/bug.c:195 [inline] report_bug+0x27c/0x500 lib/bug.c:219 handle_bug+0xe5/0x180 arch/x86/kernel/traps.c:285 exc_invalid_op+0x35/0x80 arch/x86/kernel/traps.c:309 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621 RIP: 0010:perf_trace_add+0x2da/0x390 kernel/trace/trace_event_perf.c:375 Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 64 48 89 ab f8 01 00 00 48 89 df e8 b1 ab 26 00 e9 f3 fd ff ff e8 37 87 f6 ff 90 <0f> 0b 90 41 bc ea ff ff ff e9 77 ff ff ff e8 23 c5 56 00 e9 8a fd RSP: 0018:ffffc9000713f7f0 EFLAGS: 00010006 RAX: 0000000040000002 RBX: ffff88802a069880 RCX: ffffffff8195a68e RDX: ffff888045ec2500 RSI: ffffffff8195a839 RDI: ffffffff8deabf48 RBP: 0000000000000000 R08: 0000000000000001 R09: fffff52000e27eef R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8deabee0 R14: ffff88802a069928 R15: ffff888051237200 event_sched_in+0x434/0xac0 kernel/events/core.c:2629 group_sched_in kernel/events/core.c:2662 [inline] merge_sched_in+0x895/0x1570 kernel/events/core.c:3940 visit_groups_merge.constprop.0.isra.0+0x6d2/0x1250 kernel/events/core.c:3885 pmu_groups_sched_in kernel/events/core.c:3967 [inline] __pmu_ctx_sched_in kernel/events/core.c:3979 [inline] ctx_sched_in+0x5c1/0xa30 kernel/events/core.c:4030 perf_event_sched_in+0x5d/0x90 kernel/events/core.c:2760 perf_event_context_sched_in kernel/events/core.c:4077 [inline] __perf_event_task_sched_in+0x33a/0x6f0 kernel/events/core.c:4106 perf_event_task_sched_in include/linux/perf_event.h:1524 [inline] finish_task_switch.isra.0+0x5f9/0xcb0 kernel/sched/core.c:5201 context_switch kernel/sched/core.c:5335 [inline] __schedule+0x1156/0x5b20 kernel/sched/core.c:6710 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7032 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x80 kernel/kcov.c:210 Code: 5d 41 5c 41 5d c3 cc cc cc cc 48 c7 c0 f4 ff ff ff eb 92 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 65 48 8b 15 04 ae 77 7e 65 8b 05 05 ae 77 7e a9 00 01 RSP: 0000:ffffc9000713fe20 EFLAGS: 00000212 RAX: 000000000000fe4d RBX: 0000000000000200 RCX: ffffc9002f801000 RDX: 0000000000080000 RSI: ffffffff81d2e884 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000001 R09: fffffbfff2d84fa6 R10: 0000000000000200 R11: 0000000000000000 R12: ffff888020dea000 R13: ffff88804a8558c8 R14: 0000000000000040 R15: ffff88804f13f200 rcu_read_unlock include/linux/rcupdate.h:878 [inline] count_memcg_events_mm.constprop.0+0x12a/0x330 include/linux/memcontrol.h:1046 count_memcg_event_mm include/linux/memcontrol.h:1052 [inline] mm_account_fault mm/memory.c:5947 [inline] handle_mm_fault+0x5af/0xab0 mm/memory.c:6107 do_user_addr_fault+0x61b/0x13a0 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x98/0x180 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7fe4fdc4f757 Code: 70 48 63 d5 48 01 c2 49 3b 55 08 77 4e 8d 55 ff 85 ed 74 35 0f 1f 80 00 00 00 00 48 39 c6 77 1c 49 8b 7d 00 49 89 c1 49 29 f1 <46> 0f b6 0c 0f 45 84 c9 74 08 44 88 0c 07 49 8b 45 10 48 83 c0 01 RSP: 002b:00007fe4fec1b420 EFLAGS: 00010206 RAX: 0000000000067001 RBX: 00007fe4fec1b480 RCX: 0000000000000000 RDX: 000000000000004c RSI: 0000000000000001 RDI: 00007fe4f3600000 RBP: 0000000000000102 R08: 0000000000000001 R09: 0000000000067000 R10: 0000000000000000 R11: 00007fe4fec1b490 R12: 00007fe4fec1b490 R13: 00007fe4fec1b520 R14: 0000000000000001 R15: 0000000000000000 </TASK> WARNING: CPU: 0 PID: 15835 at kernel/trace/trace_event_perf.c:375 perf_trace_add+0x2da/0x390 kernel/trace/trace_event_perf.c:375 Modules linked in: CPU: 0 UID: 0 PID: 15835 Comm: syz.9.499 Not tainted 6.12.25 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:perf_trace_add+0x2da/0x390 kernel/trace/trace_event_perf.c:375 Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 64 48 89 ab f8 01 00 00 48 89 df e8 b1 ab 26 00 e9 f3 fd ff ff e8 37 87 f6 ff 90 <0f> 0b 90 41 bc ea ff ff ff e9 77 ff ff ff e8 23 c5 56 00 e9 8a fd RSP: 0018:ffffc9000713f7f0 EFLAGS: 00010006 RAX: 0000000040000002 RBX: ffff88802a069880 RCX: ffffffff8195a68e RDX: ffff888045ec2500 RSI: ffffffff8195a839 RDI: ffffffff8deabf48 RBP: 0000000000000000 R08: 0000000000000001 R09: fffff52000e27eef R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8deabee0 R14: ffff88802a069928 R15: ffff888051237200 FS: 00007fe4fec1c640(0000) GS:ffff88802b800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f50219e7bac CR3: 00000000743bc000 CR4: 0000000000752ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 80000000 Call Trace: <TASK> event_sched_in+0x434/0xac0 kernel/events/core.c:2629 group_sched_in kernel/events/core.c:2662 [inline] merge_sched_in+0x895/0x1570 kernel/events/core.c:3940 visit_groups_merge.constprop.0.isra.0+0x6d2/0x1250 kernel/events/core.c:3885 pmu_groups_sched_in kernel/events/core.c:3967 [inline] __pmu_ctx_sched_in kernel/events/core.c:3979 [inline] ctx_sched_in+0x5c1/0xa30 kernel/events/core.c:4030 perf_event_sched_in+0x5d/0x90 kernel/events/core.c:2760 perf_event_context_sched_in kernel/events/core.c:4077 [inline] __perf_event_task_sched_in+0x33a/0x6f0 kernel/events/core.c:4106 perf_event_task_sched_in include/linux/perf_event.h:1524 [inline] finish_task_switch.isra.0+0x5f9/0xcb0 kernel/sched/core.c:5201 context_switch kernel/sched/core.c:5335 [inline] __schedule+0x1156/0x5b20 kernel/sched/core.c:6710 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7032 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x80 kernel/kcov.c:210 Code: 5d 41 5c 41 5d c3 cc cc cc cc 48 c7 c0 f4 ff ff ff eb 92 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 65 48 8b 15 04 ae 77 7e 65 8b 05 05 ae 77 7e a9 00 01 RSP: 0000:ffffc9000713fe20 EFLAGS: 00000212 RAX: 000000000000fe4d RBX: 0000000000000200 RCX: ffffc9002f801000 RDX: 0000000000080000 RSI: ffffffff81d2e884 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000001 R09: fffffbfff2d84fa6 R10: 0000000000000200 R11: 0000000000000000 R12: ffff888020dea000 R13: ffff88804a8558c8 R14: 0000000000000040 R15: ffff88804f13f200 rcu_read_unlock include/linux/rcupdate.h:878 [inline] count_memcg_events_mm.constprop.0+0x12a/0x330 include/linux/memcontrol.h:1046 count_memcg_event_mm include/linux/memcontrol.h:1052 [inline] mm_account_fault mm/memory.c:5947 [inline] handle_mm_fault+0x5af/0xab0 mm/memory.c:6107 do_user_addr_fault+0x61b/0x13a0 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x98/0x180 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7fe4fdc4f757 Code: 70 48 63 d5 48 01 c2 49 3b 55 08 77 4e 8d 55 ff 85 ed 74 35 0f 1f 80 00 00 00 00 48 39 c6 77 1c 49 8b 7d 00 49 89 c1 49 29 f1 <46> 0f b6 0c 0f 45 84 c9 74 08 44 88 0c 07 49 8b 45 10 48 83 c0 01 RSP: 002b:00007fe4fec1b420 EFLAGS: 00010206 RAX: 0000000000067001 RBX: 00007fe4fec1b480 RCX: 0000000000000000 RDX: 000000000000004c RSI: 0000000000000001 RDI: 00007fe4f3600000 RBP: 0000000000000102 R08: 0000000000000001 R09: 0000000000067000 R10: 0000000000000000 R11: 00007fe4fec1b490 R12: 00007fe4fec1b490 R13: 00007fe4fec1b520 R14: 0000000000000001 R15: 0000000000000000 </TASK> ---------------- Code disassembly (best guess): 0: 5d pop %rbp 1: 41 5c pop %r12 3: 41 5d pop %r13 5: c3 ret 6: cc int3 7: cc int3 8: cc int3 9: cc int3 a: 48 c7 c0 f4 ff ff ff mov $0xfffffffffffffff4,%rax 11: eb 92 jmp 0xffffffa5 13: 0f 1f 80 00 00 00 00 nopl 0x0(%rax) 1a: 90 nop 1b: 90 nop 1c: 90 nop 1d: 90 nop 1e: 90 nop 1f: 90 nop 20: 90 nop 21: 90 nop 22: 90 nop 23: 90 nop 24: 90 nop 25: 90 nop 26: 90 nop 27: 90 nop 28: 90 nop 29: 90 nop * 2a: f3 0f 1e fa endbr64 <-- trapping instruction 2e: 65 48 8b 15 04 ae 77 mov %gs:0x7e77ae04(%rip),%rdx # 0x7e77ae3a 35: 7e 36: 65 8b 05 05 ae 77 7e mov %gs:0x7e77ae05(%rip),%eax # 0x7e77ae42 3d: a9 .byte 0xa9 3e: 00 01 add %al,(%rcx) ===================================================================
I hope it helps. Best regards Jianzhou Zhao
On Tue, Apr 29, 2025 at 10:18:04PM +0800, Jianzhou Zhao wrote:
Hello, I found a potential bug titled " possible deadlock in perf_ctx_lock " with modified syzkaller in the Linux6.12.25(longterm maintenance, last updated on April 25, 2025)
Nah, you hit a WARN and then printk being lousy made it explode worse.
WARNING: CPU: 0 PID: 15835 at kernel/trace/trace_event_perf.c:375 perf_trace_add+0x2da/0x390 kernel/trace/trace_event_perf.c:375 Modules linked in: CPU: 0 UID: 0 PID: 15835 Comm: syz.9.499 Not tainted 6.12.25 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:perf_trace_add+0x2da/0x390 kernel/trace/trace_event_perf.c:375 Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 64 48 89 ab f8 01 00 00 48 89 df e8 b1 ab 26 00 e9 f3 fd ff ff e8 37 87 f6 ff 90 <0f> 0b 90 41 bc ea ff ff ff e9 77 ff ff ff e8 23 c5 56 00 e9 8a fd RSP: 0018:ffffc9000713f7f0 EFLAGS: 00010006 RAX: 0000000040000002 RBX: ffff88802a069880 RCX: ffffffff8195a68e RDX: ffff888045ec2500 RSI: ffffffff8195a839 RDI: ffffffff8deabf48 RBP: 0000000000000000 R08: 0000000000000001 R09: fffff52000e27eef R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8deabee0 R14: ffff88802a069928 R15: ffff888051237200 FS: 00007fe4fec1c640(0000) GS:ffff88802b800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f50219e7bac CR3: 00000000743bc000 CR4: 0000000000752ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 80000000 Call Trace:
<TASK> event_sched_in+0x434/0xac0 kernel/events/core.c:2629 group_sched_in kernel/events/core.c:2662 [inline] merge_sched_in+0x895/0x1570 kernel/events/core.c:3940 visit_groups_merge.constprop.0.isra.0+0x6d2/0x1250 kernel/events/core.c:3885 pmu_groups_sched_in kernel/events/core.c:3967 [inline] __pmu_ctx_sched_in kernel/events/core.c:3979 [inline] ctx_sched_in+0x5c1/0xa30 kernel/events/core.c:4030 perf_event_sched_in+0x5d/0x90 kernel/events/core.c:2760 perf_event_context_sched_in kernel/events/core.c:4077 [inline] __perf_event_task_sched_in+0x33a/0x6f0 kernel/events/core.c:4106 perf_event_task_sched_in include/linux/perf_event.h:1524 [inline] finish_task_switch.isra.0+0x5f9/0xcb0 kernel/sched/core.c:5201 context_switch kernel/sched/core.c:5335 [inline] __schedule+0x1156/0x5b20 kernel/sched/core.c:6710 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7032 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
Not quite sure which of the WARNs that is, as I don't keep the stable trees around and .12 is quite old by now.
Anyway, if you can reproduce I'll take a look.
linux-stable-mirror@lists.linaro.org
-
Jianzhou Zhao -
Peter Zijlstra