====================================================== WARNING: possible circular locking dependency detected 5.13.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-fuzzer/8452 is trying to acquire lock: ffffffff8c29c220 (fs_reclaim){+.+.}-{0:0}, at: fs_reclaim_acquire+0xf7/0x160 mm/page_alloc.c:4586 but task is already holding lock: ffff8880b9c31620 (lock#2){-.-.}-{2:2}, at: __alloc_pages_bulk+0x4ad/0x1870 mm/page_alloc.c:5291 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (lock#2){-.-.}-{2:2}: local_lock_acquire include/linux/local_lock_internal.h:42 [inline] free_unref_page+0x1bf/0x690 mm/page_alloc.c:3439 mm_free_pgd kernel/fork.c:636 [inline] __mmdrop+0xcb/0x3f0 kernel/fork.c:687 mmdrop include/linux/sched/mm.h:49 [inline] finish_task_switch.isra.0+0x6da/0xa50 kernel/sched/core.c:4582 context_switch kernel/sched/core.c:4686 [inline] __schedule+0x93c/0x2710 kernel/sched/core.c:5940 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6328 irqentry_exit+0x31/0x80 kernel/entry/common.c:427 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 variable_test_bit arch/x86/include/asm/bitops.h:214 [inline] test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [inline] cpumask_test_cpu include/linux/cpumask.h:344 [inline] cpu_online include/linux/cpumask.h:895 [inline] trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0xa9/0x720 kernel/locking/lockdep.c:5636 might_alloc include/linux/sched/mm.h:199 [inline] slab_pre_alloc_hook mm/slab.h:485 [inline] slab_alloc_node mm/slub.c:2891 [inline] __kmalloc_node_track_caller+0x65/0x360 mm/slub.c:4654 kmalloc_reserve net/core/skbuff.c:355 [inline] __alloc_skb+0xde/0x340 net/core/skbuff.c:426 alloc_skb include/linux/skbuff.h:1112 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1186 [inline] netlink_sendmsg+0x954/0xda0 net/netlink/af_netlink.c:1904 sock_sendmsg_nosec net/socket.c:703 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:723 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2392 ___sys_sendmsg+0xf3/0x170 net/socket.c:2446 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2475 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (fs_reclaim){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __fs_reclaim_acquire mm/page_alloc.c:4564 [inline] fs_reclaim_acquire+0x117/0x160 mm/page_alloc.c:4578 prepare_alloc_pages+0x15c/0x580 mm/page_alloc.c:5176 __alloc_pages+0x12f/0x500 mm/page_alloc.c:5375 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2272 stack_depot_save+0x39d/0x4e0 lib/stackdepot.c:303 save_stack+0x15e/0x1e0 mm/page_owner.c:120 __set_page_owner+0x50/0x290 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2445 [inline] __alloc_pages_bulk+0x8b9/0x1870 mm/page_alloc.c:5313 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline] vm_area_alloc_pages mm/vmalloc.c:2775 [inline] __vmalloc_area_node mm/vmalloc.c:2845 [inline] __vmalloc_node_range+0x39d/0x960 mm/vmalloc.c:2947 __vmalloc_node mm/vmalloc.c:2996 [inline] vzalloc+0x67/0x80 mm/vmalloc.c:3066 n_tty_open+0x16/0x170 drivers/tty/n_tty.c:1914 tty_ldisc_open+0x9b/0x110 drivers/tty/tty_ldisc.c:464 tty_ldisc_setup+0x43/0x100 drivers/tty/tty_ldisc.c:781 tty_init_dev.part.0+0x1f4/0x610 drivers/tty/tty_io.c:1461 tty_init_dev+0x5b/0x80 drivers/tty/tty_io.c:1427 ptmx_open drivers/tty/pty.c:851 [inline] ptmx_open+0x112/0x360 drivers/tty/pty.c:817 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4c8/0x11c0 fs/open.c:826 do_open fs/namei.c:3361 [inline] path_openat+0x1c0e/0x27e0 fs/namei.c:3494 do_filp_open+0x190/0x3d0 fs/namei.c:3521 do_sys_openat2+0x16d/0x420 fs/open.c:1195 do_sys_open fs/open.c:1211 [inline] __do_sys_openat fs/open.c:1227 [inline] __se_sys_openat fs/open.c:1222 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1222 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(lock#2); lock(fs_reclaim); lock(lock#2); lock(fs_reclaim); *** DEADLOCK *** 4 locks held by syz-fuzzer/8452: #0: ffffffff8cb6fce8 (tty_mutex){+.+.}-{3:3}, at: ptmx_open drivers/tty/pty.c:850 [inline] #0: ffffffff8cb6fce8 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0x103/0x360 drivers/tty/pty.c:817 #1: ffff8880354d01c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock+0xbd/0x120 drivers/tty/tty_mutex.c:20 #2: ffff8880354d0098 (&tty->ldisc_sem){++++}-{0:0}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:315 [inline] #2: ffff8880354d0098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock+0x61/0xb0 drivers/tty/tty_ldisc.c:339 #3: ffff8880b9c31620 (lock#2){-.-.}-{2:2}, at: __alloc_pages_bulk+0x4ad/0x1870 mm/page_alloc.c:5291 stack backtrace: CPU: 0 PID: 8452 Comm: syz-fuzzer Not tainted 5.13.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:96 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2131 check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __fs_reclaim_acquire mm/page_alloc.c:4564 [inline] fs_reclaim_acquire+0x117/0x160 mm/page_alloc.c:4578 prepare_alloc_pages+0x15c/0x580 mm/page_alloc.c:5176 __alloc_pages+0x12f/0x500 mm/page_alloc.c:5375 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2272 stack_depot_save+0x39d/0x4e0 lib/stackdepot.c:303 save_stack+0x15e/0x1e0 mm/page_owner.c:120 __set_page_owner+0x50/0x290 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2445 [inline] __alloc_pages_bulk+0x8b9/0x1870 mm/page_alloc.c:5313 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline] vm_area_alloc_pages mm/vmalloc.c:2775 [inline] __vmalloc_area_node mm/vmalloc.c:2845 [inline] __vmalloc_node_range+0x39d/0x960 mm/vmalloc.c:2947 __vmalloc_node mm/vmalloc.c:2996 [inline] vzalloc+0x67/0x80 mm/vmalloc.c:3066 n_tty_open+0x16/0x170 drivers/tty/n_tty.c:1914 tty_ldisc_open+0x9b/0x110 drivers/tty/tty_ldisc.c:464 tty_ldisc_setup+0x43/0x100 drivers/tty/tty_ldisc.c:781 tty_init_dev.part.0+0x1f4/0x610 drivers/tty/tty_io.c:1461 tty_init_dev+0x5b/0x80 drivers/tty/tty_io.c:1427 ptmx_open drivers/tty/pty.c:851 [inline] ptmx_open+0x112/0x360 drivers/tty/pty.c:817 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4c8/0x11c0 fs/open.c:826 do_open fs/namei.c:3361 [inline] path_openat+0x1c0e/0x27e0 fs/namei.c:3494 do_filp_open+0x190/0x3d0 fs/namei.c:3521 do_sys_openat2+0x16d/0x420 fs/open.c:1195 do_sys_open fs/open.c:1211 [inline] __do_sys_openat fs/open.c:1227 [inline] __se_sys_openat fs/open.c:1222 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1222 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4af20a Code: e8 3b 82 fb ff 48 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 4c 8b 54 24 28 4c 8b 44 24 30 4c 8b 4c 24 38 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 40 ff ff ff ff 48 c7 44 24 48 RSP: 002b:000000c0003793f8 EFLAGS: 00000216 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000000c00001e800 RCX: 00000000004af20a RDX: 0000000000000000 RSI: 000000c0001e58b0 RDI: ffffffffffffff9c RBP: 000000c000379470 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000216 R12: 000000000000018c R13: 000000000000018b R14: 0000000000000200 R15: 000000c0004b4000 BUG: sleeping function called from invalid context at mm/page_alloc.c:5179 in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 8452, name: syz-fuzzer INFO: lockdep is turned off. irq event stamp: 149170 hardirqs last enabled at (149169): [] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] hardirqs last enabled at (149169): [] _raw_spin_unlock_irqrestore+0x50/0x70 kernel/locking/spinlock.c:191 hardirqs last disabled at (149170): [] __alloc_pages_bulk+0x1017/0x1870 mm/page_alloc.c:5291 softirqs last enabled at (146440): [] invoke_softirq kernel/softirq.c:432 [inline] softirqs last enabled at (146440): [] __irq_exit_rcu+0x16e/0x1c0 kernel/softirq.c:636 softirqs last disabled at (146431): [] invoke_softirq kernel/softirq.c:432 [inline] softirqs last disabled at (146431): [] __irq_exit_rcu+0x16e/0x1c0 kernel/softirq.c:636 CPU: 0 PID: 8452 Comm: syz-fuzzer Not tainted 5.13.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:96 ___might_sleep.cold+0x1f1/0x237 kernel/sched/core.c:9153 prepare_alloc_pages+0x3da/0x580 mm/page_alloc.c:5179 __alloc_pages+0x12f/0x500 mm/page_alloc.c:5375 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2272 stack_depot_save+0x39d/0x4e0 lib/stackdepot.c:303 save_stack+0x15e/0x1e0 mm/page_owner.c:120 __set_page_owner+0x50/0x290 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2445 [inline] __alloc_pages_bulk+0x8b9/0x1870 mm/page_alloc.c:5313 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline] vm_area_alloc_pages mm/vmalloc.c:2775 [inline] __vmalloc_area_node mm/vmalloc.c:2845 [inline] __vmalloc_node_range+0x39d/0x960 mm/vmalloc.c:2947 __vmalloc_node mm/vmalloc.c:2996 [inline] vzalloc+0x67/0x80 mm/vmalloc.c:3066 n_tty_open+0x16/0x170 drivers/tty/n_tty.c:1914 tty_ldisc_open+0x9b/0x110 drivers/tty/tty_ldisc.c:464 tty_ldisc_setup+0x43/0x100 drivers/tty/tty_ldisc.c:781 tty_init_dev.part.0+0x1f4/0x610 drivers/tty/tty_io.c:1461 tty_init_dev+0x5b/0x80 drivers/tty/tty_io.c:1427 ptmx_open drivers/tty/pty.c:851 [inline] ptmx_open+0x112/0x360 drivers/tty/pty.c:817 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4c8/0x11c0 fs/open.c:826 do_open fs/namei.c:3361 [inline] path_openat+0x1c0e/0x27e0 fs/namei.c:3494 do_filp_open+0x190/0x3d0 fs/namei.c:3521 do_sys_openat2+0x16d/0x420 fs/open.c:1195 do_sys_open fs/open.c:1211 [inline] __do_sys_openat fs/open.c:1227 [inline] __se_sys_openat fs/open.c:1222 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1222 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4af20a Code: e8 3b 82 fb ff 48 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 4c 8b 54 24 28 4c 8b 44 24 30 4c 8b 4c 24 38 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 40 ff ff ff ff 48 c7 44 24 48 RSP: 002b:000000c0003793f8 EFLAGS: 00000216 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000000c00001e800 RCX: 00000000004af20a RDX: 0000000000000000 RSI: 000000c0001e58b0 RDI: ffffffffffffff9c RBP: 000000c000379470 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000216 R12: 000000000000018c R13: 000000000000018b R14: 0000000000000200 R15: 000000c0004b4000 can: request_module (can-proto-0) failed. can: request_module (can-proto-0) failed. can: request_module (can-proto-0) failed. base_sock_release(ffff88803ae38fc0) sk=ffff8880392ab000