Hello, The following program triggers deadlock warnings on genl_mutex:
https://gist.githubusercontent.com/dvyukov/65e33d053e507d2ab0bf6ae83d989585/raw/b3c640ec58e894b50bcbf255c471406466cfa5d0/gistfile1.txt On commit 16ae16c6e5616c084168740990fc508bda6655d4 (Nov 24). BUG: sleeping function called from invalid context at kernel/locking/mutex.c:620 in_atomic(): 1, irqs_disabled(): 0, pid: 32289, name: syz-executor CPU: 0 PID: 32289 Comm: syz-executor Not tainted 4.9.0-rc5+ #54 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 ffff88003ec06420 ffffffff834c2e39 ffffffff00000000 1ffff10007d80c17 ffffed0007d80c0f 0000000041b58ab3 ffffffff89575550 ffffffff834c2b4b ffffffff8baab1a0 dffffc0000000000 0000000000000000 ffff880068f794e0 Call Trace: <IRQ> [ 287.394552] [< inline >] __dump_stack lib/dump_stack.c:15 <IRQ> [ 287.394552] [<ffffffff834c2e39>] dump_stack+0x2ee/0x3f5 lib/dump_stack.c:51 [<ffffffff814b6ac3>] ___might_sleep+0x483/0x660 kernel/sched/core.c:7761 [<ffffffff814b6d3a>] __might_sleep+0x9a/0x1a0 kernel/sched/core.c:7720 [<ffffffff88139aaa>] mutex_lock_nested+0x1ea/0xf20 kernel/locking/mutex.c:620 [< inline >] genl_lock net/netlink/genetlink.c:31 [<ffffffff86cb5a11>] genl_lock_done+0x71/0xd0 net/netlink/genetlink.c:531 [<ffffffff86ca5458>] netlink_sock_destruct+0xf8/0x400 net/netlink/af_netlink.c:331 [<ffffffff86a7b234>] __sk_destruct+0xf4/0x7f0 net/core/sock.c:1423 [<ffffffff86a87d6c>] sk_destruct+0x4c/0x80 net/core/sock.c:1453 [<ffffffff86a87dfc>] __sk_free+0x5c/0x230 net/core/sock.c:1461 [<ffffffff86a87ff8>] sk_free+0x28/0x30 net/core/sock.c:1472 [< inline >] sock_put include/net/sock.h:1591 [<ffffffff86ca6cd1>] deferred_put_nlk_sk+0x31/0x40 net/netlink/af_netlink.c:652 [< inline >] __rcu_reclaim kernel/rcu/rcu.h:118 [<ffffffff815cbc9d>] rcu_do_batch.isra.70+0x9ed/0xe20 kernel/rcu/tree.c:2776 [< inline >] invoke_rcu_callbacks kernel/rcu/tree.c:3040 [< inline >] __rcu_process_callbacks kernel/rcu/tree.c:3007 [<ffffffff815cc55c>] rcu_process_callbacks+0x48c/0xd70 kernel/rcu/tree.c:3024 [<ffffffff8814d53b>] __do_softirq+0x32b/0xca8 kernel/softirq.c:284 [< inline >] invoke_softirq kernel/softirq.c:364 [<ffffffff8141a941>] irq_exit+0x1d1/0x210 kernel/softirq.c:405 [< inline >] exiting_irq arch/x86/include/asm/apic.h:659 [<ffffffff8814ca30>] smp_apic_timer_interrupt+0x80/0xa0 arch/x86/kernel/apic/apic.c:960 [<ffffffff8814badc>] apic_timer_interrupt+0x8c/0xa0 arch/x86/entry/entry_64.S:489 <EOI> [ 287.403717] [<ffffffff8155c987>] ? lock_is_held+0x247/0x310 [<ffffffff814b6bde>] ___might_sleep+0x59e/0x660 kernel/sched/core.c:7729 [<ffffffff814b6d3a>] __might_sleep+0x9a/0x1a0 kernel/sched/core.c:7720 [<ffffffff88142d08>] down_read+0x78/0x160 kernel/locking/rwsem.c:21 [< inline >] anon_vma_lock_read include/linux/rmap.h:127 [<ffffffff81968295>] validate_mm+0xe5/0x880 mm/mmap.c:347 [<ffffffff8196bf0b>] vma_link+0x11b/0x180 mm/mmap.c:605 [<ffffffff81977f46>] mmap_region+0x1076/0x1880 mm/mmap.c:1692 [<ffffffff81978e4f>] do_mmap+0x6ff/0xe80 mm/mmap.c:1450 [< inline >] do_mmap_pgoff include/linux/mm.h:2039 [<ffffffff818fd527>] vm_mmap_pgoff+0x1b7/0x210 mm/util.c:305 [< inline >] SYSC_mmap_pgoff mm/mmap.c:1500 [<ffffffff8196f961>] SyS_mmap_pgoff+0x231/0x5e0 mm/mmap.c:1458 [< inline >] SYSC_mmap arch/x86/kernel/sys_x86_64.c:95 [<ffffffff8124bf4b>] SyS_mmap+0x1b/0x30 arch/x86/kernel/sys_x86_64.c:86 [<ffffffff88149dc5>] entry_SYSCALL_64_fastpath+0x23/0xc6 ================================= [ INFO: inconsistent lock state ] 4.9.0-rc5+ #54 Tainted: G W --------------------------------- inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. syz-executor/32289 [HC0[0]:SC1[1]:HE1:SE0] takes: ([ 287.580014] genl_mutex [< inline >] genl_lock net/netlink/genetlink.c:31 [<ffffffff86cb5a11>] genl_lock_done+0x71/0xd0 net/netlink/genetlink.c:531 {SOFTIRQ-ON-W} state was registered at: [ 287.580014] [< inline >] mark_irqflags kernel/locking/lockdep.c:2938 [ 287.580014] [<ffffffff81567ad7>] __lock_acquire+0x6e7/0x3380 kernel/locking/lockdep.c:3292 [ 287.580014] [<ffffffff8156b642>] lock_acquire+0x2a2/0x790 kernel/locking/lockdep.c:3746 [ 287.580014] [< inline >] __mutex_lock_common kernel/locking/mutex.c:521 [ 287.580014] [<ffffffff88139aff>] mutex_lock_nested+0x23f/0xf20 kernel/locking/mutex.c:621 [ 287.580014] [< inline >] genl_lock net/netlink/genetlink.c:31 [ 287.580014] [< inline >] genl_lock_all net/netlink/genetlink.c:52 [ 287.580014] [<ffffffff86cba52e>] __genl_register_family+0x2ce/0x1870 net/netlink/genetlink.c:374 [ 287.580014] [< inline >] _genl_register_family_with_ops_grps include/net/genetlink.h:173 [ 287.580014] [<ffffffff8ab90c02>] genl_init+0x11d/0x185 net/netlink/genetlink.c:1084 [ 287.580014] [<ffffffff8100244b>] do_one_initcall+0xfb/0x3f0 init/main.c:778 [ 287.580014] [< inline >] do_initcall_level init/main.c:844 [ 287.580014] [< inline >] do_initcalls init/main.c:852 [ 287.580014] [< inline >] do_basic_setup init/main.c:870 [ 287.580014] [<ffffffff8aa3d03d>] kernel_init_freeable+0x5c4/0x69e init/main.c:1017 [ 287.580014] [<ffffffff88129c88>] kernel_init+0x18/0x180 init/main.c:943 [ 287.580014] [<ffffffff8814a05a>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433 [ 78.258919] [ INFO: inconsistent lock state ] [ 78.258919] 4.9.0-rc5+ #54 Tainted: G W [ 78.258919] --------------------------------- [ 78.258919] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [ 78.258919] syz-fuzzer/5211 [HC0[0]:SC1[1]:HE1:SE0] takes: [ 78.258919] ([ 78.258919] genl_mutex ){+.?.+.}[ 78.258919] , at: [ 78.258919] [<ffffffff86cb5a11>] genl_lock_done+0x71/0xd0 [ 78.258919] {SOFTIRQ-ON-W} state was registered at: [ 78.258919] [ 78.258919] [<ffffffff81567ad7>] __lock_acquire+0x6e7/0x3380 [ 78.258919] [ 78.258919] [<ffffffff8156b642>] lock_acquire+0x2a2/0x790 [ 78.258919] [ 78.258919] [<ffffffff88139aff>] mutex_lock_nested+0x23f/0xf20 [ 78.258919] [ 78.258919] [<ffffffff86cba52e>] __genl_register_family+0x2ce/0x1870 [ 78.258919] [ 78.258919] [<ffffffff8ab90c02>] genl_init+0x11d/0x185 [ 78.258919] [ 78.258919] [<ffffffff8100244b>] do_one_initcall+0xfb/0x3f0 [ 78.258919] [ 78.258919] [<ffffffff8aa3d03d>] kernel_init_freeable+0x5c4/0x69e [ 78.258919] [ 78.258919] [<ffffffff88129c88>] kernel_init+0x18/0x180 [ 78.258919] [ 78.258919] [<ffffffff8814a05a>] ret_from_fork+0x2a/0x40 [ 78.258919] irq event stamp: 149484 [ 78.258919] hardirqs last enabled at (149484): [ 78.258919] [<ffffffff8814a7df>] restore_regs_and_iret+0x0/0x1d [ 78.258919] hardirqs last disabled at (149483): [ 78.258919] [<ffffffff8814bad7>] apic_timer_interrupt+0x87/0xa0 [ 78.258919] softirqs last enabled at (149302): [ 78.258919] [<ffffffff8814da39>] __do_softirq+0x829/0xca8 [ 78.258919] softirqs last disabled at (149437): [ 78.258919] [<ffffffff8141a941>] irq_exit+0x1d1/0x210 [ 78.258919] [ 78.258919] other info that might help us debug this: [ 78.258919] Possible unsafe locking scenario: [ 78.258919] [ 78.258919] CPU0 [ 78.258919] ---- [ 78.258919] lock([ 78.258919] genl_mutex [ 78.258919] ); [ 78.258919] <Interrupt> [ 78.258919] lock([ 78.258919] genl_mutex [ 78.258919] ); [ 78.258919] [ 78.258919] *** DEADLOCK *** [ 78.258919] [ 78.258919] 1 lock held by syz-fuzzer/5211: [ 78.258919] #0: [ 78.258919] ( rcu_callback[ 78.258919] ){......} , at: [ 78.258919] [<ffffffff815cbc43>] rcu_do_batch.isra.70+0x993/0xe20 [ 78.258919] [ 78.258919] stack backtrace: CPU: 0 PID: 32289 Comm: syz-executor Tainted: G W 4.9.0-rc5+ #54 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 ffff88003ec05db8 ffffffff834c2e39 ffffffff00000000 1ffff10007d80b4a ffffed0007d80b42 0000000041b58ab3 ffffffff89575550 ffffffff834c2b4b ffff88003948a340 ffff88003ec22cc0 ffff8800384dd280 0000000041b58ab3 Call Trace: <IRQ> [ 287.580014] [< inline >] __dump_stack lib/dump_stack.c:15 <IRQ> [ 287.580014] [<ffffffff834c2e39>] dump_stack+0x2ee/0x3f5 lib/dump_stack.c:51 [<ffffffff815648df>] print_usage_bug+0x3ef/0x450 kernel/locking/lockdep.c:2388 [< inline >] valid_state kernel/locking/lockdep.c:2401 [< inline >] mark_lock_irq kernel/locking/lockdep.c:2599 [<ffffffff81565870>] mark_lock+0xf30/0x1410 kernel/locking/lockdep.c:3062 [< inline >] mark_irqflags kernel/locking/lockdep.c:2920 [<ffffffff8156811e>] __lock_acquire+0xd2e/0x3380 kernel/locking/lockdep.c:3292 [<ffffffff8156b642>] lock_acquire+0x2a2/0x790 kernel/locking/lockdep.c:3746 [< inline >] __mutex_lock_common kernel/locking/mutex.c:521 [<ffffffff88139aff>] mutex_lock_nested+0x23f/0xf20 kernel/locking/mutex.c:621 [< inline >] genl_lock net/netlink/genetlink.c:31 [<ffffffff86cb5a11>] genl_lock_done+0x71/0xd0 net/netlink/genetlink.c:531 [<ffffffff86ca5458>] netlink_sock_destruct+0xf8/0x400 net/netlink/af_netlink.c:331 [<ffffffff86a7b234>] __sk_destruct+0xf4/0x7f0 net/core/sock.c:1423 [<ffffffff86a87d6c>] sk_destruct+0x4c/0x80 net/core/sock.c:1453 [<ffffffff86a87dfc>] __sk_free+0x5c/0x230 net/core/sock.c:1461 [<ffffffff86a87ff8>] sk_free+0x28/0x30 net/core/sock.c:1472 [< inline >] sock_put include/net/sock.h:1591 [<ffffffff86ca6cd1>] deferred_put_nlk_sk+0x31/0x40 net/netlink/af_netlink.c:652 [< inline >] __rcu_reclaim kernel/rcu/rcu.h:118 [<ffffffff815cbc9d>] rcu_do_batch.isra.70+0x9ed/0xe20 kernel/rcu/tree.c:2776 [< inline >] invoke_rcu_callbacks kernel/rcu/tree.c:3040 [< inline >] __rcu_process_callbacks kernel/rcu/tree.c:3007 [<ffffffff815cc55c>] rcu_process_callbacks+0x48c/0xd70 kernel/rcu/tree.c:3024 [<ffffffff8814d53b>] __do_softirq+0x32b/0xca8 kernel/softirq.c:284 [< inline >] invoke_softirq kernel/softirq.c:364 [<ffffffff8141a941>] irq_exit+0x1d1/0x210 kernel/softirq.c:405 [< inline >] exiting_irq arch/x86/include/asm/apic.h:659 [<ffffffff8814ca30>] smp_apic_timer_interrupt+0x80/0xa0 arch/x86/kernel/apic/apic.c:960 [<ffffffff8814badc>] apic_timer_interrupt+0x8c/0xa0 arch/x86/entry/entry_64.S:489 <EOI> [ 287.580014] [<ffffffff8155c987>] ? lock_is_held+0x247/0x310 [<ffffffff814b6bde>] ___might_sleep+0x59e/0x660 kernel/sched/core.c:7729 [<ffffffff814b6d3a>] __might_sleep+0x9a/0x1a0 kernel/sched/core.c:7720 [<ffffffff88142d08>] down_read+0x78/0x160 kernel/locking/rwsem.c:21 [< inline >] anon_vma_lock_read include/linux/rmap.h:127 [<ffffffff81968295>] validate_mm+0xe5/0x880 mm/mmap.c:347 [<ffffffff8196bf0b>] vma_link+0x11b/0x180 mm/mmap.c:605 [<ffffffff81977f46>] mmap_region+0x1076/0x1880 mm/mmap.c:1692 [<ffffffff81978e4f>] do_mmap+0x6ff/0xe80 mm/mmap.c:1450 [< inline >] do_mmap_pgoff include/linux/mm.h:2039 [<ffffffff818fd527>] vm_mmap_pgoff+0x1b7/0x210 mm/util.c:305 [< inline >] SYSC_mmap_pgoff mm/mmap.c:1500 [<ffffffff8196f961>] SyS_mmap_pgoff+0x231/0x5e0 mm/mmap.c:1458 [< inline >] SYSC_mmap arch/x86/kernel/sys_x86_64.c:95 [<ffffffff8124bf4b>] SyS_mmap+0x1b/0x30 arch/x86/kernel/sys_x86_64.c:86 [<ffffffff88149dc5>] entry_SYSCALL_64_fastpath+0x23/0xc6
