====================================================== WARNING: possible circular locking dependency detected 6.11.0-rc6-syzkaller-00308-gb31c44928842 #0 Not tainted ------------------------------------------------------ syz.2.11/5436 is trying to acquire lock: ffff888030a178b0 (&htab->lockdep_key#2){-.-.}-{2:2}, at: htab_lock_bucket kernel/bpf/hashtab.c:167 [inline] ffff888030a178b0 (&htab->lockdep_key#2){-.-.}-{2:2}, at: htab_map_delete_elem+0x1c8/0x730 kernel/bpf/hashtab.c:1426 but task is already holding lock: ffff8881052058b0 (&htab->lockdep_key){-.-.}-{2:2}, at: htab_lock_bucket kernel/bpf/hashtab.c:167 [inline] ffff8881052058b0 (&htab->lockdep_key){-.-.}-{2:2}, at: htab_map_delete_elem+0x1c8/0x730 kernel/bpf/hashtab.c:1426 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&htab->lockdep_key){-.-.}-{2:2}: __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 htab_lock_bucket kernel/bpf/hashtab.c:167 [inline] htab_map_delete_elem+0x1c8/0x730 kernel/bpf/hashtab.c:1426 bpf_prog_1a158c95e143a564+0x45/0x4e bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2406 [inline] bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2447 __bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122 __traceiter_contention_end+0x5a/0xa0 include/trace/events/lock.h:122 trace_contention_end.constprop.0+0xea/0x170 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x27e/0xc90 kernel/locking/qspinlock.c:557 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x210/0x2c0 kernel/locking/spinlock_debug.c:116 htab_lock_bucket kernel/bpf/hashtab.c:167 [inline] htab_map_delete_elem+0x1c8/0x730 kernel/bpf/hashtab.c:1426 bpf_prog_1a158c95e143a564+0x45/0x4e bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2406 [inline] bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2447 __bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122 __traceiter_contention_end+0x5a/0xa0 include/trace/events/lock.h:122 trace_contention_end+0xce/0x140 include/trace/events/lock.h:122 __mutex_lock_common kernel/locking/mutex.c:617 [inline] __mutex_lock+0x19c/0x9c0 kernel/locking/mutex.c:752 rng_dev_read+0x128/0x720 drivers/char/hw_random/core.c:218 do_loop_readv_writev fs/read_write.c:761 [inline] do_loop_readv_writev fs/read_write.c:749 [inline] vfs_readv+0x6cb/0x8a0 fs/read_write.c:934 do_preadv fs/read_write.c:1049 [inline] __do_sys_preadv fs/read_write.c:1099 [inline] __se_sys_preadv fs/read_write.c:1094 [inline] __x64_sys_preadv+0x22b/0x310 fs/read_write.c:1094 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&htab->lockdep_key#2){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3133 [inline] check_prevs_add kernel/locking/lockdep.c:3252 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142 lock_acquire kernel/locking/lockdep.c:5759 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 htab_lock_bucket kernel/bpf/hashtab.c:167 [inline] htab_map_delete_elem+0x1c8/0x730 kernel/bpf/hashtab.c:1426 bpf_prog_1a158c95e143a564+0x45/0x4e bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2406 [inline] bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2447 __bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122 __traceiter_contention_end+0x5a/0xa0 include/trace/events/lock.h:122 trace_contention_end.constprop.0+0xea/0x170 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x27e/0xc90 kernel/locking/qspinlock.c:557 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x210/0x2c0 kernel/locking/spinlock_debug.c:116 htab_lock_bucket kernel/bpf/hashtab.c:167 [inline] htab_map_delete_elem+0x1c8/0x730 kernel/bpf/hashtab.c:1426 bpf_prog_1a158c95e143a564+0x45/0x4e bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2406 [inline] bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2447 __bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122 __traceiter_contention_end+0x5a/0xa0 include/trace/events/lock.h:122 trace_contention_end+0xce/0x140 include/trace/events/lock.h:122 __mutex_lock_common kernel/locking/mutex.c:617 [inline] __mutex_lock+0x19c/0x9c0 kernel/locking/mutex.c:752 __kernfs_iattrs fs/kernfs/inode.c:32 [inline] kernfs_iattrs_noalloc fs/kernfs/inode.c:65 [inline] kernfs_xattr_get+0x29/0xa0 fs/kernfs/inode.c:298 selinux_kernfs_init_security+0x11a/0x4d0 security/selinux/hooks.c:3560 security_kernfs_init_security+0x6d/0xc0 security/security.c:2698 __kernfs_new_node+0x564/0x890 fs/kernfs/dir.c:663 kernfs_new_node+0x186/0x240 fs/kernfs/dir.c:700 __kernfs_create_file+0x53/0x350 fs/kernfs/file.c:1034 sysfs_add_file_mode_ns+0x1ff/0x3b0 fs/sysfs/file.c:307 create_files fs/sysfs/group.c:76 [inline] internal_create_group+0x565/0xe50 fs/sysfs/group.c:180 internal_create_groups+0x9d/0x150 fs/sysfs/group.c:220 device_add_groups drivers/base/core.c:2829 [inline] device_add_attrs drivers/base/core.c:2893 [inline] device_add+0x6d3/0x1a70 drivers/base/core.c:3636 netdev_register_kobject+0x187/0x3f0 net/core/net-sysfs.c:2136 register_netdevice+0x1473/0x1e90 net/core/dev.c:10444 register_netdev+0x2f/0x50 net/core/dev.c:10581 ip6gre_init_net+0x2fe/0x450 net/ipv6/ip6_gre.c:1628 ops_init+0xb9/0x650 net/core/net_namespace.c:139 setup_net+0x435/0xb40 net/core/net_namespace.c:343 copy_net_ns+0x2fb/0x700 net/core/net_namespace.c:508 create_new_namespaces+0x3ea/0xad0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:228 ksys_unshare+0x419/0x970 kernel/fork.c:3309 __do_sys_unshare kernel/fork.c:3380 [inline] __se_sys_unshare kernel/fork.c:3378 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3378 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&htab->lockdep_key); lock(&htab->lockdep_key#2); lock(&htab->lockdep_key); lock(&htab->lockdep_key#2); *** DEADLOCK *** 6 locks held by syz.2.11/5436: #0: ffffffff8fa201d0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2d6/0x700 net/core/net_namespace.c:504 #1: ffffffff8fa35be8 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x13/0x50 net/core/dev.c:10579 #2: ffffffff8e007728 (iattr_mutex){+.+.}-{3:3}, at: __kernfs_iattrs fs/kernfs/inode.c:32 [inline] #2: ffffffff8e007728 (iattr_mutex){+.+.}-{3:3}, at: kernfs_iattrs_noalloc fs/kernfs/inode.c:65 [inline] #2: ffffffff8e007728 (iattr_mutex){+.+.}-{3:3}, at: kernfs_xattr_get+0x29/0xa0 fs/kernfs/inode.c:298 #3: ffffffff8ddb9fe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline] #3: ffffffff8ddb9fe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #3: ffffffff8ddb9fe0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2405 [inline] #3: ffffffff8ddb9fe0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1c2/0x590 kernel/trace/bpf_trace.c:2447 #4: ffff8881052058b0 (&htab->lockdep_key){-.-.}-{2:2}, at: htab_lock_bucket kernel/bpf/hashtab.c:167 [inline] #4: ffff8881052058b0 (&htab->lockdep_key){-.-.}-{2:2}, at: htab_map_delete_elem+0x1c8/0x730 kernel/bpf/hashtab.c:1426 #5: ffffffff8ddb9fe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:326 [inline] #5: ffffffff8ddb9fe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #5: ffffffff8ddb9fe0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2405 [inline] #5: ffffffff8ddb9fe0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1c2/0x590 kernel/trace/bpf_trace.c:2447 stack backtrace: CPU: 1 UID: 0 PID: 5436 Comm: syz.2.11 Not tainted 6.11.0-rc6-syzkaller-00308-gb31c44928842 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2186 check_prev_add kernel/locking/lockdep.c:3133 [inline] check_prevs_add kernel/locking/lockdep.c:3252 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142 lock_acquire kernel/locking/lockdep.c:5759 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 htab_lock_bucket kernel/bpf/hashtab.c:167 [inline] htab_map_delete_elem+0x1c8/0x730 kernel/bpf/hashtab.c:1426 bpf_prog_1a158c95e143a564+0x45/0x4e bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2406 [inline] bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2447 __bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122 __traceiter_contention_end+0x5a/0xa0 include/trace/events/lock.h:122 trace_contention_end.constprop.0+0xea/0x170 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x27e/0xc90 kernel/locking/qspinlock.c:557 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x210/0x2c0 kernel/locking/spinlock_debug.c:116 htab_lock_bucket kernel/bpf/hashtab.c:167 [inline] htab_map_delete_elem+0x1c8/0x730 kernel/bpf/hashtab.c:1426 bpf_prog_1a158c95e143a564+0x45/0x4e bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run include/linux/filter.h:698 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2406 [inline] bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2447 __bpf_trace_contention_end+0xca/0x110 include/trace/events/lock.h:122 __traceiter_contention_end+0x5a/0xa0 include/trace/events/lock.h:122 trace_contention_end+0xce/0x140 include/trace/events/lock.h:122 __mutex_lock_common kernel/locking/mutex.c:617 [inline] __mutex_lock+0x19c/0x9c0 kernel/locking/mutex.c:752 __kernfs_iattrs fs/kernfs/inode.c:32 [inline] kernfs_iattrs_noalloc fs/kernfs/inode.c:65 [inline] kernfs_xattr_get+0x29/0xa0 fs/kernfs/inode.c:298 selinux_kernfs_init_security+0x11a/0x4d0 security/selinux/hooks.c:3560 security_kernfs_init_security+0x6d/0xc0 security/security.c:2698 __kernfs_new_node+0x564/0x890 fs/kernfs/dir.c:663 kernfs_new_node+0x186/0x240 fs/kernfs/dir.c:700 __kernfs_create_file+0x53/0x350 fs/kernfs/file.c:1034 sysfs_add_file_mode_ns+0x1ff/0x3b0 fs/sysfs/file.c:307 create_files fs/sysfs/group.c:76 [inline] internal_create_group+0x565/0xe50 fs/sysfs/group.c:180 internal_create_groups+0x9d/0x150 fs/sysfs/group.c:220 device_add_groups drivers/base/core.c:2829 [inline] device_add_attrs drivers/base/core.c:2893 [inline] device_add+0x6d3/0x1a70 drivers/base/core.c:3636 netdev_register_kobject+0x187/0x3f0 net/core/net-sysfs.c:2136 register_netdevice+0x1473/0x1e90 net/core/dev.c:10444 register_netdev+0x2f/0x50 net/core/dev.c:10581 ip6gre_init_net+0x2fe/0x450 net/ipv6/ip6_gre.c:1628 ops_init+0xb9/0x650 net/core/net_namespace.c:139 setup_net+0x435/0xb40 net/core/net_namespace.c:343 copy_net_ns+0x2fb/0x700 net/core/net_namespace.c:508 create_new_namespaces+0x3ea/0xad0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:228 ksys_unshare+0x419/0x970 kernel/fork.c:3309 __do_sys_unshare kernel/fork.c:3380 [inline] __se_sys_unshare kernel/fork.c:3378 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3378 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe29437cef9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe2951ca038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007fe294536058 RCX: 00007fe29437cef9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000068040200 RBP: 00007fe2943ef046 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fe294536058 R15: 00007ffe42250e58