===================================================== WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected 6.8.0-syzkaller-05243-g14bb1e8c8d4a #0 Not tainted ----------------------------------------------------- syz-executor.1/20243 [HC0[0]:SC0[2]:HE0:SE0] is trying to acquire: ffff88802398a0f8 (&htab->buckets[i].lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] ffff88802398a0f8 (&htab->buckets[i].lock){+...}-{2:2}, at: sock_hash_delete_elem+0xb0/0x300 net/core/sock_map.c:939 and this task is already holding: ffffffff8e136558 (rcu_node_0){-.-.}-{2:2}, at: rcu_note_context_switch+0x2a9/0xff0 kernel/rcu/tree_plugin.h:326 which would create a new lock dependency: (rcu_node_0){-.-.}-{2:2} -> (&htab->buckets[i].lock){+...}-{2:2} but this new dependency connects a HARDIRQ-irq-safe lock: (rcu_node_0){-.-.}-{2:2} ... which became HARDIRQ-irq-safe at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 rcu_report_exp_cpu_mult+0x27/0x2f0 kernel/rcu/tree_exp.h:238 csd_do_func kernel/smp.c:133 [inline] __flush_smp_call_function_queue+0xb2e/0x15b0 kernel/smp.c:542 __sysvec_call_function_single+0xa8/0x3e0 arch/x86/kernel/smp.c:271 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline] sysvec_call_function_single+0x9e/0xc0 arch/x86/kernel/smp.c:266 asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709 unwind_done arch/x86/include/asm/unwind.h:50 [inline] arch_stack_walk+0x158/0x1b0 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:312 [inline] __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3813 [inline] slab_alloc_node mm/slub.c:3860 [inline] kmem_cache_alloc+0x172/0x350 mm/slub.c:3867 kmem_cache_zalloc include/linux/slab.h:701 [inline] __kernfs_new_node+0xd8/0x880 fs/kernfs/dir.c:615 kernfs_new_node+0x13a/0x240 fs/kernfs/dir.c:691 __kernfs_create_file+0x49/0x2f0 fs/kernfs/file.c:1025 sysfs_add_file_mode_ns+0x24a/0x310 fs/sysfs/file.c:307 sysfs_merge_group+0x1fd/0x450 fs/sysfs/group.c:346 dpm_sysfs_add+0xd3/0x280 drivers/base/power/sysfs.c:707 device_add+0x5c3/0xca0 drivers/base/core.c:3599 __add_memory_block drivers/base/memory.c:668 [inline] add_memory_block+0x2d0/0x530 drivers/base/memory.c:790 memory_dev_init+0x105/0x1b0 drivers/base/memory.c:962 driver_init+0x42/0x60 drivers/base/init.c:38 do_basic_setup+0x16/0x90 init/main.c:1335 kernel_init_freeable+0x435/0x5d0 init/main.c:1557 kernel_init+0x1d/0x2a0 init/main.c:1446 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 to a HARDIRQ-irq-unsafe lock: (&htab->buckets[i].lock){+...}-{2:2} ... which became HARDIRQ-irq-unsafe at: ... lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] sock_hash_update_common+0x20c/0xa30 net/core/sock_map.c:1007 sock_map_update_elem_sys+0x5a4/0x910 net/core/sock_map.c:581 map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1641 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5619 __do_sys_bpf kernel/bpf/syscall.c:5738 [inline] __se_sys_bpf kernel/bpf/syscall.c:5736 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5736 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&htab->buckets[i].lock); local_irq_disable(); lock(rcu_node_0); lock(&htab->buckets[i].lock); lock(rcu_node_0); *** DEADLOCK *** 6 locks held by syz-executor.1/20243: #0: ffffffff8e1dadf0 (dup_mmap_sem){++++}-{0:0}, at: dup_mmap kernel/fork.c:637 [inline] #0: ffffffff8e1dadf0 (dup_mmap_sem){++++}-{0:0}, at: dup_mm kernel/fork.c:1687 [inline] #0: ffffffff8e1dadf0 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x272/0x21b0 kernel/fork.c:1736 #1: ffff88802f373120 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:124 [inline] #1: ffff88802f373120 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:638 [inline] #1: ffff88802f373120 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1687 [inline] #1: ffff88802f373120 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x292/0x21b0 kernel/fork.c:1736 #2: ffff888063d273a0 (&mm->mmap_lock/1){+.+.}-{3:3}, at: mmap_write_lock_nested include/linux/mmap_lock.h:115 [inline] #2: ffff888063d273a0 (&mm->mmap_lock/1){+.+.}-{3:3}, at: dup_mmap kernel/fork.c:647 [inline] #2: ffff888063d273a0 (&mm->mmap_lock/1){+.+.}-{3:3}, at: dup_mm kernel/fork.c:1687 [inline] #2: ffff888063d273a0 (&mm->mmap_lock/1){+.+.}-{3:3}, at: copy_mm+0x3cc/0x21b0 kernel/fork.c:1736 #3: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #3: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #3: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: __pte_offset_map+0x82/0x380 mm/pgtable-generic.c:285 #4: ffffffff8e136558 (rcu_node_0){-.-.}-{2:2}, at: rcu_note_context_switch+0x2a9/0xff0 kernel/rcu/tree_plugin.h:326 #5: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #5: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #5: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2395 [inline] #5: ffffffff8e131920 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1fc/0x530 kernel/trace/bpf_trace.c:2437 the dependencies between HARDIRQ-irq-safe lock and the holding lock: -> (rcu_node_0){-.-.}-{2:2} { IN-HARDIRQ-W at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 rcu_report_exp_cpu_mult+0x27/0x2f0 kernel/rcu/tree_exp.h:238 csd_do_func kernel/smp.c:133 [inline] __flush_smp_call_function_queue+0xb2e/0x15b0 kernel/smp.c:542 __sysvec_call_function_single+0xa8/0x3e0 arch/x86/kernel/smp.c:271 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline] sysvec_call_function_single+0x9e/0xc0 arch/x86/kernel/smp.c:266 asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709 unwind_done arch/x86/include/asm/unwind.h:50 [inline] arch_stack_walk+0x158/0x1b0 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:312 [inline] __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3813 [inline] slab_alloc_node mm/slub.c:3860 [inline] kmem_cache_alloc+0x172/0x350 mm/slub.c:3867 kmem_cache_zalloc include/linux/slab.h:701 [inline] __kernfs_new_node+0xd8/0x880 fs/kernfs/dir.c:615 kernfs_new_node+0x13a/0x240 fs/kernfs/dir.c:691 __kernfs_create_file+0x49/0x2f0 fs/kernfs/file.c:1025 sysfs_add_file_mode_ns+0x24a/0x310 fs/sysfs/file.c:307 sysfs_merge_group+0x1fd/0x450 fs/sysfs/group.c:346 dpm_sysfs_add+0xd3/0x280 drivers/base/power/sysfs.c:707 device_add+0x5c3/0xca0 drivers/base/core.c:3599 __add_memory_block drivers/base/memory.c:668 [inline] add_memory_block+0x2d0/0x530 drivers/base/memory.c:790 memory_dev_init+0x105/0x1b0 drivers/base/memory.c:962 driver_init+0x42/0x60 drivers/base/init.c:38 do_basic_setup+0x16/0x90 init/main.c:1335 kernel_init_freeable+0x435/0x5d0 init/main.c:1557 kernel_init+0x1d/0x2a0 init/main.c:1446 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 IN-SOFTIRQ-W at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 rcu_report_qs_rdp kernel/rcu/tree.c:2018 [inline] rcu_check_quiescent_state kernel/rcu/tree.c:2100 [inline] rcu_core+0x3ae/0x1830 kernel/rcu/tree.c:2455 __do_softirq+0x2bc/0x943 kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633 irq_exit_rcu+0x9/0x30 kernel/softirq.c:645 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 rcu_is_watching+0x70/0xb0 kernel/rcu/tree.c:702 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0xe3/0x530 kernel/locking/lockdep.c:5725 fs_reclaim_acquire+0xaf/0x130 mm/page_alloc.c:3709 might_alloc include/linux/sched/mm.h:303 [inline] slab_pre_alloc_hook mm/slub.c:3761 [inline] slab_alloc_node mm/slub.c:3842 [inline] kmalloc_trace+0x47/0x360 mm/slub.c:4007 kmalloc include/linux/slab.h:590 [inline] kzalloc include/linux/slab.h:711 [inline] ddebug_add_module+0x88/0x800 lib/dynamic_debug.c:1240 dynamic_debug_init+0x205/0x5a0 lib/dynamic_debug.c:1446 do_one_initcall+0x238/0x830 init/main.c:1241 do_pre_smp_initcalls+0x57/0xa0 init/main.c:1347 kernel_init_freeable+0x40d/0x5d0 init/main.c:1546 kernel_init+0x1d/0x2a0 init/main.c:1446 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 INITIAL USE at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 rcutree_prepare_cpu+0x71/0x640 kernel/rcu/tree.c:4484 rcu_init+0x9b/0x140 kernel/rcu/tree.c:5224 start_kernel+0x1f7/0x500 init/main.c:969 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:509 x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:490 common_startup_64+0x13e/0x147 } ... key at: [] rcu_init_one.rcu_node_class+0x0/0x20 the dependencies between the lock to be acquired and HARDIRQ-irq-unsafe lock: -> (&htab->buckets[i].lock){+...}-{2:2} { HARDIRQ-ON-W at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] sock_hash_update_common+0x20c/0xa30 net/core/sock_map.c:1007 sock_map_update_elem_sys+0x5a4/0x910 net/core/sock_map.c:581 map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1641 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5619 __do_sys_bpf kernel/bpf/syscall.c:5738 [inline] __se_sys_bpf kernel/bpf/syscall.c:5736 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5736 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 INITIAL USE at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] sock_hash_update_common+0x20c/0xa30 net/core/sock_map.c:1007 sock_map_update_elem_sys+0x5a4/0x910 net/core/sock_map.c:581 map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1641 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5619 __do_sys_bpf kernel/bpf/syscall.c:5738 [inline] __se_sys_bpf kernel/bpf/syscall.c:5736 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5736 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 } ... key at: [] sock_hash_alloc.__key+0x0/0x20 ... acquired at: lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] sock_hash_delete_elem+0xb0/0x300 net/core/sock_map.c:939 bpf_prog_8b502551ebbde0c1+0x42/0x4b bpf_dispatcher_nop_func include/linux/bpf.h:1233 [inline] __bpf_prog_run include/linux/filter.h:667 [inline] bpf_prog_run include/linux/filter.h:674 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2396 [inline] bpf_trace_run2+0x2ec/0x530 kernel/trace/bpf_trace.c:2437 trace_contention_begin+0xf9/0x120 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0x115/0xc60 kernel/locking/qspinlock.c:405 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline] queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x272/0x370 kernel/locking/spinlock_debug.c:116 rcu_note_context_switch+0x2a9/0xff0 kernel/rcu/tree_plugin.h:326 __schedule+0x345/0x4a20 kernel/sched/core.c:6635 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6915 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6939 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1126 [inline] copy_pmd_range mm/memory.c:1187 [inline] copy_pud_range mm/memory.c:1224 [inline] copy_p4d_range mm/memory.c:1248 [inline] copy_page_range+0x3763/0x4240 mm/memory.c:1346 dup_mmap kernel/fork.c:747 [inline] dup_mm kernel/fork.c:1687 [inline] copy_mm+0x12f5/0x21b0 kernel/fork.c:1736 copy_process+0x187a/0x3df0 kernel/fork.c:2389 kernel_clone+0x21e/0x8d0 kernel/fork.c:2796 __do_sys_clone kernel/fork.c:2939 [inline] __se_sys_clone kernel/fork.c:2923 [inline] __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2923 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 stack backtrace: CPU: 1 PID: 20243 Comm: syz-executor.1 Not tainted 6.8.0-syzkaller-05243-g14bb1e8c8d4a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 print_bad_irq_dependency kernel/locking/lockdep.c:2626 [inline] check_irq_usage kernel/locking/lockdep.c:2865 [inline] check_prev_add kernel/locking/lockdep.c:3138 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x4dc7/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] sock_hash_delete_elem+0xb0/0x300 net/core/sock_map.c:939 bpf_prog_8b502551ebbde0c1+0x42/0x4b bpf_dispatcher_nop_func include/linux/bpf.h:1233 [inline] __bpf_prog_run include/linux/filter.h:667 [inline] bpf_prog_run include/linux/filter.h:674 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2396 [inline] bpf_trace_run2+0x2ec/0x530 kernel/trace/bpf_trace.c:2437 trace_contention_begin+0xf9/0x120 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0x115/0xc60 kernel/locking/qspinlock.c:405 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline] queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x272/0x370 kernel/locking/spinlock_debug.c:116 rcu_note_context_switch+0x2a9/0xff0 kernel/rcu/tree_plugin.h:326 __schedule+0x345/0x4a20 kernel/sched/core.c:6635 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6915 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6939 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1126 [inline] copy_pmd_range mm/memory.c:1187 [inline] copy_pud_range mm/memory.c:1224 [inline] copy_p4d_range mm/memory.c:1248 [inline] copy_page_range+0x3763/0x4240 mm/memory.c:1346 dup_mmap kernel/fork.c:747 [inline] dup_mm kernel/fork.c:1687 [inline] copy_mm+0x12f5/0x21b0 kernel/fork.c:1736 copy_process+0x187a/0x3df0 kernel/fork.c:2389 kernel_clone+0x21e/0x8d0 kernel/fork.c:2796 __do_sys_clone kernel/fork.c:2939 [inline] __se_sys_clone kernel/fork.c:2923 [inline] __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2923 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7fcf2767add3 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007fff89f921f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcf2767add3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 000055555a4b0750 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001