====================================================== WARNING: possible circular locking dependency detected 6.1.0-rc5-syzkaller-00144-g84368d882b96 #0 Not tainted ------------------------------------------------------ syz-executor.3/3942 is trying to acquire lock: ffffffff8c6cf5e8 (zonelist_update_seq.seqcount){...-}-{0:0}, at: __alloc_pages+0x4aa/0x5b0 mm/page_alloc.c:5568 but task is already holding lock: ffff88802c829418 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x60c/0xe30 kernel/time/timer.c:1096 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&base->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 lock_timer_base+0x5a/0x1f0 kernel/time/timer.c:999 __mod_timer+0x398/0xe30 kernel/time/timer.c:1072 __queue_delayed_work+0x1a7/0x270 kernel/workqueue.c:1676 queue_delayed_work_on+0x109/0x120 kernel/workqueue.c:1701 psi_task_change+0x1bf/0x2f0 kernel/sched/psi.c:833 psi_enqueue kernel/sched/stats.h:141 [inline] enqueue_task+0x1ec/0x3a0 kernel/sched/core.c:2056 activate_task kernel/sched/core.c:2085 [inline] wake_up_new_task+0x632/0xdb0 kernel/sched/core.c:4688 kernel_clone+0x229/0x980 kernel/fork.c:2702 user_mode_thread+0xb1/0xf0 kernel/fork.c:2747 rest_init+0x27/0x270 init/main.c:694 arch_call_rest_init+0x13/0x1c init/main.c:890 start_kernel+0x477/0x498 init/main.c:1145 secondary_startup_64_no_verify+0xce/0xdb -> #3 (&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:537 raw_spin_rq_lock kernel/sched/sched.h:1354 [inline] rq_lock kernel/sched/sched.h:1644 [inline] task_fork_fair+0x6c/0x520 kernel/sched/fair.c:11608 sched_cgroup_fork+0x3d1/0x540 kernel/sched/core.c:4632 copy_process+0x4351/0x7190 kernel/fork.c:2370 kernel_clone+0xeb/0x980 kernel/fork.c:2671 user_mode_thread+0xb1/0xf0 kernel/fork.c:2747 rest_init+0x27/0x270 init/main.c:694 arch_call_rest_init+0x13/0x1c init/main.c:890 start_kernel+0x477/0x498 init/main.c:1145 secondary_startup_64_no_verify+0xce/0xdb -> #2 (&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 try_to_wake_up+0xb2/0x20f0 kernel/sched/core.c:4076 up+0x79/0xb0 kernel/locking/semaphore.c:191 __up_console_sem+0xa4/0xc0 kernel/printk/printk.c:260 __console_unlock kernel/printk/printk.c:2651 [inline] console_unlock+0x4ce/0x600 kernel/printk/printk.c:2862 vga_remove_vgacon drivers/pci/vgaarb.c:189 [inline] vga_remove_vgacon.cold+0x99/0x9e drivers/pci/vgaarb.c:170 bochs_pci_probe+0x105/0x880 drivers/gpu/drm/tiny/bochs.c:653 local_pci_probe+0xe5/0x1a0 drivers/pci/pci-driver.c:324 pci_call_probe drivers/pci/pci-driver.c:392 [inline] __pci_device_probe drivers/pci/pci-driver.c:417 [inline] pci_device_probe+0x2a3/0x7f0 drivers/pci/pci-driver.c:460 call_driver_probe drivers/base/dd.c:560 [inline] really_probe+0x249/0xb90 drivers/base/dd.c:639 __driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:778 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:808 __driver_attach+0x1d4/0x550 drivers/base/dd.c:1190 bus_for_each_dev+0x14b/0x1d0 drivers/base/bus.c:301 bus_add_driver+0x4cd/0x640 drivers/base/bus.c:618 driver_register+0x224/0x3a0 drivers/base/driver.c:246 drm_pci_register_driver_if_modeset include/drm/drm_module.h:69 [inline] bochs_pci_driver_init+0x75/0x84 drivers/gpu/drm/tiny/bochs.c:731 do_one_initcall+0x141/0x780 init/main.c:1303 do_initcall_level init/main.c:1376 [inline] do_initcalls init/main.c:1392 [inline] do_basic_setup init/main.c:1411 [inline] kernel_init_freeable+0x6ff/0x788 init/main.c:1631 kernel_init+0x1e/0x1d0 init/main.c:1519 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 -> #1 ((console_sem).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 down_trylock+0x12/0x70 kernel/locking/semaphore.c:139 __down_trylock_console_sem+0x40/0x120 kernel/printk/printk.c:243 console_trylock kernel/printk/printk.c:2585 [inline] console_trylock_spinning kernel/printk/printk.c:1867 [inline] vprintk_emit+0x16b/0x600 kernel/printk/printk.c:2267 vprintk+0x84/0xa0 kernel/printk/printk_safe.c:50 _printk+0xbe/0xf1 kernel/printk/printk.c:2289 build_zonelists+0x2e7/0x400 mm/page_alloc.c:6500 __build_all_zonelists+0x122/0x180 mm/page_alloc.c:6616 build_all_zonelists_init+0x35/0x12f mm/page_alloc.c:6641 build_all_zonelists+0x123/0x140 mm/page_alloc.c:6674 start_kernel+0xbd/0x498 init/main.c:967 secondary_startup_64_no_verify+0xce/0xdb -> #0 (zonelist_update_seq.seqcount){...-}-{0:0}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 seqcount_lockdep_reader_access include/linux/seqlock.h:102 [inline] read_seqbegin include/linux/seqlock.h:836 [inline] zonelist_iter_begin mm/page_alloc.c:4727 [inline] __alloc_pages_slowpath.constprop.0+0x1ae/0x23d0 mm/page_alloc.c:5049 __alloc_pages+0x4aa/0x5b0 mm/page_alloc.c:5568 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2285 __stack_depot_save+0x3ed/0x560 lib/stackdepot.c:474 kasan_save_stack+0x35/0x40 mm/kasan/common.c:46 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 __kasan_slab_alloc+0x82/0x90 mm/kasan/common.c:325 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slab.h:737 [inline] slab_alloc_node mm/slub.c:3398 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc+0x2b4/0x3d0 mm/slub.c:3422 kmem_cache_zalloc include/linux/slab.h:679 [inline] fill_pool+0x264/0x5c0 lib/debugobjects.c:168 __debug_object_init+0x7a/0xd10 lib/debugobjects.c:562 debug_object_init lib/debugobjects.c:617 [inline] debug_object_activate+0x330/0x3e0 lib/debugobjects.c:703 debug_timer_activate kernel/time/timer.c:782 [inline] __mod_timer+0x77d/0xe30 kernel/time/timer.c:1103 fl_release+0x1dd/0x250 net/ipv6/ip6_flowlabel.c:143 fl6_free_socklist+0x172/0x280 net/ipv6/ip6_flowlabel.c:295 inet6_destroy_sock+0x108/0x220 net/ipv6/af_inet6.c:507 inet_csk_destroy_sock+0x19a/0x440 net/ipv4/inet_connection_sock.c:1157 dccp_close+0xa41/0xd60 net/dccp/proto.c:1060 inet_release+0x132/0x270 net/ipv4/af_inet.c:428 inet6_release+0x50/0x70 net/ipv6/af_inet6.c:488 __sock_release+0xcd/0x280 net/socket.c:650 sock_close+0x1c/0x20 net/socket.c:1365 __fput+0x27c/0xa90 fs/file_table.c:320 task_work_run+0x16f/0x270 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 __do_fast_syscall_32+0x72/0xf0 arch/x86/entry/common.c:181 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 other info that might help us debug this: Chain exists of: zonelist_update_seq.seqcount --> &rq->__lock --> &base->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&base->lock); lock(&rq->__lock); lock(&base->lock); lock(zonelist_update_seq.seqcount); *** DEADLOCK *** 4 locks held by syz-executor.3/3942: #0: ffff888028709410 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline] #0: ffff888028709410 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:649 #1: ffff888042fd9630 (slock-AF_INET6){+...}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #1: ffff888042fd9630 (slock-AF_INET6){+...}-{2:2}, at: dccp_close+0x56c/0xd60 net/dccp/proto.c:1050 #2: ffffffff8e094138 (ip6_fl_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline] #2: ffffffff8e094138 (ip6_fl_lock){+...}-{2:2}, at: fl_release+0x1a/0x250 net/ipv6/ip6_flowlabel.c:128 #3: ffff88802c829418 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x60c/0xe30 kernel/time/timer.c:1096 stack backtrace: CPU: 2 PID: 3942 Comm: syz-executor.3 Not tainted 6.1.0-rc5-syzkaller-00144-g84368d882b96 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 seqcount_lockdep_reader_access include/linux/seqlock.h:102 [inline] read_seqbegin include/linux/seqlock.h:836 [inline] zonelist_iter_begin mm/page_alloc.c:4727 [inline] __alloc_pages_slowpath.constprop.0+0x1ae/0x23d0 mm/page_alloc.c:5049 __alloc_pages+0x4aa/0x5b0 mm/page_alloc.c:5568 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2285 __stack_depot_save+0x3ed/0x560 lib/stackdepot.c:474 kasan_save_stack+0x35/0x40 mm/kasan/common.c:46 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 __kasan_slab_alloc+0x82/0x90 mm/kasan/common.c:325 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slab.h:737 [inline] slab_alloc_node mm/slub.c:3398 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc+0x2b4/0x3d0 mm/slub.c:3422 kmem_cache_zalloc include/linux/slab.h:679 [inline] fill_pool+0x264/0x5c0 lib/debugobjects.c:168 __debug_object_init+0x7a/0xd10 lib/debugobjects.c:562 debug_object_init lib/debugobjects.c:617 [inline] debug_object_activate+0x330/0x3e0 lib/debugobjects.c:703 debug_timer_activate kernel/time/timer.c:782 [inline] __mod_timer+0x77d/0xe30 kernel/time/timer.c:1103 fl_release+0x1dd/0x250 net/ipv6/ip6_flowlabel.c:143 fl6_free_socklist+0x172/0x280 net/ipv6/ip6_flowlabel.c:295 inet6_destroy_sock+0x108/0x220 net/ipv6/af_inet6.c:507 inet_csk_destroy_sock+0x19a/0x440 net/ipv4/inet_connection_sock.c:1157 dccp_close+0xa41/0xd60 net/dccp/proto.c:1060 inet_release+0x132/0x270 net/ipv4/af_inet.c:428 inet6_release+0x50/0x70 net/ipv6/af_inet6.c:488 __sock_release+0xcd/0x280 net/socket.c:650 sock_close+0x1c/0x20 net/socket.c:1365 __fput+0x27c/0xa90 fs/file_table.c:320 task_work_run+0x16f/0x270 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x23c/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 __do_fast_syscall_32+0x72/0xf0 arch/x86/entry/common.c:181 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7f96549 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000fff19590 EFLAGS: 00000282 ORIG_RAX: 0000000000000006 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 00000000f734c000 RDI: 0000000000000000 RBP: 00000000f6e00938 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 03 74 c0 01 add 0x1(%rax,%rax,8),%esi 4: 10 05 03 74 b8 01 adc %al,0x1b87403(%rip) # 0x1b8740d a: 10 06 adc %al,(%rsi) c: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 10: 10 07 adc %al,(%rdi) 12: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi 16: 10 08 adc %cl,(%rax) 18: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1c: 00 00 add %al,(%rax) 1e: 00 00 add %al,(%rax) 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 retq 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 39: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi