Hello, syzbot found the following issue on: HEAD commit: f31817cbcf48 Add linux-next specific files for 20231116 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=17d0aca7680000 kernel config: https://syzkaller.appspot.com/x/.config?x=f59345f1d0a928c dashboard link: https://syzkaller.appspot.com/bug?extid=cef555184e66963dabc2 compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/987488cb251e/disk-f31817cb.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/6d4a82d8bd4b/vmlinux-f31817cb.xz kernel image: https://storage.googleapis.com/syzbot-assets/fc43dee9cb86/bzImage-f31817cb.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+cef555184e66963dabc2@xxxxxxxxxxxxxxxxxxxxxxxxx ===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 6.7.0-rc1-next-20231116-syzkaller #0 Not tainted ----------------------------------------------------- syz-executor.3/8188 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffff88801f641298 (&sighand->siglock){+.+.}-{2:2}, at: __lock_task_sighand+0xc2/0x340 kernel/signal.c:1422 and this task is already holding: ffffffff8cff86b8 (css_set_lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:376 [inline] ffffffff8cff86b8 (css_set_lock){..-.}-{2:2}, at: cgroup_migrate_execute+0xd8/0x1230 kernel/cgroup/cgroup.c:2566 which would create a new lock dependency: (css_set_lock){..-.}-{2:2} -> (&sighand->siglock){+.+.}-{2:2} but this new dependency connects a SOFTIRQ-irq-safe lock: (css_set_lock){..-.}-{2:2} ... which became SOFTIRQ-irq-safe at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 put_css_set kernel/cgroup/cgroup-internal.h:208 [inline] put_css_set kernel/cgroup/cgroup-internal.h:196 [inline] cgroup_free+0x7c/0x1d0 kernel/cgroup/cgroup.c:6748 __put_task_struct+0x10b/0x3d0 kernel/fork.c:992 put_task_struct include/linux/sched/task.h:136 [inline] put_task_struct include/linux/sched/task.h:123 [inline] delayed_put_task_struct+0x22c/0x2d0 kernel/exit.c:227 rcu_do_batch kernel/rcu/tree.c:2158 [inline] rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2431 __do_softirq+0x216/0x8d5 kernel/softirq.c:553 invoke_softirq kernel/softirq.c:427 [inline] __irq_exit_rcu kernel/softirq.c:632 [inline] irq_exit_rcu+0xb5/0x120 kernel/softirq.c:644 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1076 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 lock_acquire+0x1f2/0x530 kernel/locking/lockdep.c:5721 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] lockref_put_or_lock+0x18/0x80 lib/lockref.c:147 fast_dput fs/dcache.c:775 [inline] fast_dput fs/dcache.c:765 [inline] dput+0x4c4/0xd90 fs/dcache.c:900 shmem_unlink+0x1bc/0x310 mm/shmem.c:3373 shmem_rename2+0x1ff/0x3b0 mm/shmem.c:3451 vfs_rename+0xe20/0x1c30 fs/namei.c:4844 do_renameat2+0xc3c/0xdc0 fs/namei.c:4996 __do_sys_rename fs/namei.c:5042 [inline] __se_sys_rename fs/namei.c:5040 [inline] __x64_sys_rename+0x81/0xa0 fs/namei.c:5040 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a to a SOFTIRQ-irq-unsafe lock: (&sighand->siglock){+.+.}-{2:2} ... which became SOFTIRQ-irq-unsafe at: ... lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] class_spinlock_constructor include/linux/spinlock.h:530 [inline] ptrace_set_stopped kernel/ptrace.c:391 [inline] ptrace_attach+0x401/0x650 kernel/ptrace.c:478 __do_sys_ptrace+0x204/0x230 kernel/ptrace.c:1290 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sighand->siglock); local_irq_disable(); lock(css_set_lock); lock(&sighand->siglock); <Interrupt> lock(css_set_lock); *** DEADLOCK *** 8 locks held by syz-executor.3/8188: #0: ffff88801d0e0d48 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe7/0x170 fs/file.c:1177 #1: ffff888014b44420 (sb_writers#10){.+.+}-{0:0}, at: ksys_write+0x12f/0x250 fs/read_write.c:637 #2: ffff88807ad7f088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x27d/0x500 fs/kernfs/file.c:325 #3: ffffffff8cff8768 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:368 [inline] #3: ffffffff8cff8768 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock_and_drain_offline+0xad/0x6d0 kernel/cgroup/cgroup.c:3092 #4: ffffffff8ce51f70 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2413 [inline] #4: ffffffff8ce51f70 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_update_dfl_csses+0x2fb/0x640 kernel/cgroup/cgroup.c:3050 #5: ffffffff8cff8530 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2415 [inline] #5: ffffffff8cff8530 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2411 [inline] #5: ffffffff8cff8530 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_update_dfl_csses+0x3d1/0x640 kernel/cgroup/cgroup.c:3050 #6: ffffffff8cff86b8 (css_set_lock){..-.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:376 [inline] #6: ffffffff8cff86b8 (css_set_lock){..-.}-{2:2}, at: cgroup_migrate_execute+0xd8/0x1230 kernel/cgroup/cgroup.c:2566 #7: ffffffff8cfad060 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:301 [inline] #7: ffffffff8cfad060 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline] #7: ffffffff8cfad060 (rcu_read_lock){....}-{1:2}, at: __lock_task_sighand+0x3f/0x340 kernel/signal.c:1405 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (css_set_lock){..-.}-{2:2} { IN-SOFTIRQ-W at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 put_css_set kernel/cgroup/cgroup-internal.h:208 [inline] put_css_set kernel/cgroup/cgroup-internal.h:196 [inline] cgroup_free+0x7c/0x1d0 kernel/cgroup/cgroup.c:6748 __put_task_struct+0x10b/0x3d0 kernel/fork.c:992 put_task_struct include/linux/sched/task.h:136 [inline] put_task_struct include/linux/sched/task.h:123 [inline] delayed_put_task_struct+0x22c/0x2d0 kernel/exit.c:227 rcu_do_batch kernel/rcu/tree.c:2158 [inline] rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2431 __do_softirq+0x216/0x8d5 kernel/softirq.c:553 invoke_softirq kernel/softirq.c:427 [inline] __irq_exit_rcu kernel/softirq.c:632 [inline] irq_exit_rcu+0xb5/0x120 kernel/softirq.c:644 sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1076 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 lock_acquire+0x1f2/0x530 kernel/locking/lockdep.c:5721 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] lockref_put_or_lock+0x18/0x80 lib/lockref.c:147 fast_dput fs/dcache.c:775 [inline] fast_dput fs/dcache.c:765 [inline] dput+0x4c4/0xd90 fs/dcache.c:900 shmem_unlink+0x1bc/0x310 mm/shmem.c:3373 shmem_rename2+0x1ff/0x3b0 mm/shmem.c:3451 vfs_rename+0xe20/0x1c30 fs/namei.c:4844 do_renameat2+0xc3c/0xdc0 fs/namei.c:4996 __do_sys_rename fs/namei.c:5042 [inline] __se_sys_rename fs/namei.c:5040 [inline] __x64_sys_rename+0x81/0xa0 fs/namei.c:5040 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:376 [inline] cgroup_setup_root+0x62c/0xa00 kernel/cgroup/cgroup.c:2138 cgroup_init+0x23f/0x1100 kernel/cgroup/cgroup.c:6120 start_kernel+0x385/0x480 init/main.c:1063 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:555 x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x166/0x16b } ... key at: [<ffffffff8cff86b8>] css_set_lock+0x18/0x60 the dependencies between the lock to be acquired and SOFTIRQ-irq-unsafe lock: -> (&sighand->siglock){+.+.}-{2:2} { HARDIRQ-ON-W at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] class_spinlock_constructor include/linux/spinlock.h:530 [inline] ptrace_set_stopped kernel/ptrace.c:391 [inline] ptrace_attach+0x401/0x650 kernel/ptrace.c:478 __do_sys_ptrace+0x204/0x230 kernel/ptrace.c:1290 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a SOFTIRQ-ON-W at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] class_spinlock_constructor include/linux/spinlock.h:530 [inline] ptrace_set_stopped kernel/ptrace.c:391 [inline] ptrace_attach+0x401/0x650 kernel/ptrace.c:478 __do_sys_ptrace+0x204/0x230 kernel/ptrace.c:1290 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:376 [inline] calculate_sigpending+0x44/0xa0 kernel/signal.c:197 ret_from_fork+0x23/0x80 arch/x86/kernel/process.c:143 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 } ... key at: [<ffffffff90b49f80>] __key.341+0x0/0x40 ... acquired at: lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 __lock_task_sighand+0xc2/0x340 kernel/signal.c:1422 lock_task_sighand include/linux/sched/signal.h:748 [inline] cgroup_freeze_task+0x80/0x190 kernel/cgroup/freezer.c:160 cgroup_freezer_migrate_task+0x1b7/0x3a0 kernel/cgroup/freezer.c:257 cgroup_migrate_execute+0x2d3/0x1230 kernel/cgroup/cgroup.c:2580 cgroup_update_dfl_csses+0x51b/0x640 kernel/cgroup/cgroup.c:3068 cgroup_apply_control kernel/cgroup/cgroup.c:3308 [inline] cgroup_subtree_control_write+0xb94/0xed0 kernel/cgroup/cgroup.c:3453 cgroup_file_write+0x209/0x7c0 kernel/cgroup/cgroup.c:4092 kernfs_fop_write_iter+0x33f/0x500 fs/kernfs/file.c:334 call_write_iter include/linux/fs.h:2021 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x64d/0xdf0 fs/read_write.c:584 ksys_write+0x12f/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a stack backtrace: CPU: 1 PID: 8188 Comm: syz-executor.3 Not tainted 6.7.0-rc1-next-20231116-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_bad_irq_dependency kernel/locking/lockdep.c:2626 [inline] check_irq_usage+0xe18/0x1470 kernel/locking/lockdep.c:2865 check_prev_add kernel/locking/lockdep.c:3138 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x247c/0x3b10 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1b1/0x530 kernel/locking/lockdep.c:5718 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 __lock_task_sighand+0xc2/0x340 kernel/signal.c:1422 lock_task_sighand include/linux/sched/signal.h:748 [inline] cgroup_freeze_task+0x80/0x190 kernel/cgroup/freezer.c:160 cgroup_freezer_migrate_task+0x1b7/0x3a0 kernel/cgroup/freezer.c:257 cgroup_migrate_execute+0x2d3/0x1230 kernel/cgroup/cgroup.c:2580 cgroup_update_dfl_csses+0x51b/0x640 kernel/cgroup/cgroup.c:3068 cgroup_apply_control kernel/cgroup/cgroup.c:3308 [inline] cgroup_subtree_control_write+0xb94/0xed0 kernel/cgroup/cgroup.c:3453 cgroup_file_write+0x209/0x7c0 kernel/cgroup/cgroup.c:4092 kernfs_fop_write_iter+0x33f/0x500 fs/kernfs/file.c:334 call_write_iter include/linux/fs.h:2021 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x64d/0xdf0 fs/read_write.c:584 ksys_write+0x12f/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x62/0x6a RIP: 0033:0x7f83f387cae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f83f466d0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f83f399bf80 RCX: 00007f83f387cae9 RDX: 0000000000000006 RSI: 0000000020000100 RDI: 0000000000000004 RBP: 00007f83f38c847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f83f399bf80 R15: 00007ffdda059fd8 </TASK> --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
