linux - 在linux内核中查找锁统计信息

标签 linux linux-kernel

最近研究Linux锁机制，想看看锁的持有和等待时间。

因此，我通过 make menuconfig 打开 .config 文件中的 CONFIG_LOCK_STAT 标志，并在重新编译内核后运行命令:

# less /proc/lock_stat

我收到以下消息:

*WARNING* lock debugging disabled!! - possibly due to a lockdep warning.

只是不知道为什么，因为我已经打开了内核 hack->lock session 中的所有标志。

附注我使用的环境:kernel 3.12.6(by uname -a)。

更新:dmesg 与 __debug_locks_off() 和 dump_stack() 打开

[    0.000000]  [<ffffffff817516a2>] _raw_write_lock+0x72/0x80
[    0.000000]  [<ffffffff81392718>] ? irqsafe4_soft_wlock_213+0x98/0xf0
[    0.000000]  [<ffffffff81392718>] irqsafe4_soft_wlock_213+0x98/0xf0
[    0.000000]  [<ffffffff817481f5>] dotest+0x43/0x5a7
[    0.000000]  [<ffffffff81399cd6>] locking_selftest+0x1286/0x2100
[    0.000000]  [<ffffffff81f1aca9>] start_kernel+0x2d2/0x427
[    0.000000]  [<ffffffff81f1a120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff81f1a4c7>] x86_64_start_reservations+0x2a/0x2c
[    0.000000]  [<ffffffff81f1a5d6>] x86_64_start_kernel+0x10d/0x11c
[    0.000000]   ok  |  ok  |
[    0.000000]     hard-safe-A + unsafe-B #2/231:### __debug_locks_off called!
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.6 #13
[    0.000000] Hardware name: Sony Corporation VGN-Z25TN_B/VAIO, BIOS R2140M3 08/26/2008
[    0.000000]  0000000000000002 ffffffff81c01c38 ffffffff81747f7c ffffffff81c15c98
[    0.000000]  ffffffff81c01c48 ffffffff81383d27 ffffffff81c01d60 ffffffff810d9d1e
[    0.000000]  ffffffff81c01ff8 ffffffff81c00000 ffffffff81c01fe8 ffffffff824d2d58
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff81747f7c>] dump_stack+0x54/0x74
[    0.000000]  [<ffffffff81383d27>] debug_locks_off+0x17/0x50
[    0.000000]  [<ffffffff810d9d1e>] check_usage+0x10e/0x550
[    0.000000]  [<ffffffff810170f4>] ? dump_trace+0x194/0x2f0
[    0.000000]  [<ffffffff810d6a54>] ? __bfs+0x24/0x240
[    0.000000]  [<ffffffff810da1af>] check_irq_usage+0x4f/0xc0
[    0.000000]  [<ffffffff810dd1ae>] __lock_acquire+0x1bce/0x2190
[    0.000000]  [<ffffffff817511e7>] ? _raw_spin_unlock_irqrestore+0x67/0x70
[    0.000000]  [<ffffffff810c13b6>] ? vprintk_emit+0x1d6/0x630
[    0.000000]  [<ffffffff810de882>] lock_acquire+0xb2/0x160
[    0.000000]  [<ffffffff8138b936>] ? irqsafe4_hard_spin_231+0xc6/0x110
[    0.000000]  [<ffffffff8138b870>] ? irqsafe4_hard_rlock_231+0x110/0x110
[    0.000000]  [<ffffffff81750e96>] _raw_spin_lock+0x46/0x80
[    0.000000]  [<ffffffff8138b936>] ? irqsafe4_hard_spin_231+0xc6/0x110
[    0.000000]  [<ffffffff8138b936>] irqsafe4_hard_spin_231+0xc6/0x110
[    0.000000]  [<ffffffff817481f5>] dotest+0x43/0x5a7
[    0.000000]  [<ffffffff81399d22>] locking_selftest+0x12d2/0x2100
[    0.000000]  [<ffffffff81f1aca9>] start_kernel+0x2d2/0x427
[    0.000000]  [<ffffffff81f1a120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff81f1a4c7>] x86_64_start_reservations+0x2a/0x2c
[    0.000000]  [<ffffffff81f1a5d6>] x86_64_start_kernel+0x10d/0x11c
[    0.000000] ### __debug_locks_off called!
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.6 #13
[    0.000000] Hardware name: Sony Corporation VGN-Z25TN_B/VAIO, BIOS R2140M3 08/26/2008
[    0.000000]  ffffffff81c15580 ffffffff81c01e78 ffffffff81747f7c ffffffff81cab258
[    0.000000]  ffffffff81c01e88 ffffffff81383d27 ffffffff81c01ed8 ffffffff810df539
[    0.000000]  0000000000000082 ffffffff8138b936 0000000000000092 ffffffff81cab258
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff81747f7c>] dump_stack+0x54/0x74
[    0.000000]  [<ffffffff81383d27>] debug_locks_off+0x17/0x50
[    0.000000]  [<ffffffff810df539>] lock_acquired+0x2f9/0x4d0
[    0.000000]  [<ffffffff8138b936>] ? irqsafe4_hard_spin_231+0xc6/0x110
[    0.000000]  [<ffffffff8138b870>] ? irqsafe4_hard_rlock_231+0x110/0x110
[    0.000000]  [<ffffffff81750ec2>] _raw_spin_lock+0x72/0x80
[    0.000000]  [<ffffffff8138b936>] ? irqsafe4_hard_spin_231+0xc6/0x110
[    0.000000]  [<ffffffff8138b936>] irqsafe4_hard_spin_231+0xc6/0x110
[    0.000000]  [<ffffffff817481f5>] dotest+0x43/0x5a7
[    0.000000]  [<ffffffff81399d22>] locking_selftest+0x12d2/0x2100
[    0.000000]  [<ffffffff81f1aca9>] start_kernel+0x2d2/0x427
[    0.000000]  [<ffffffff81f1a120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff81f1a4c7>] x86_64_start_reservations+0x2a/0x2c
[    0.000000]  [<ffffffff81f1a5d6>] x86_64_start_kernel+0x10d/0x11c
[    0.000000]   ok  |### __debug_locks_off called!
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.6 #13
[    0.000000] Hardware name: Sony Corporation VGN-Z25TN_B/VAIO, BIOS R2140M3 08/26/2008
[    0.000000]  0000000000000002 ffffffff81c01c38 ffffffff81747f7c ffffffff81c15c98
[    0.000000]  ffffffff81c01c48 ffffffff81383d27 ffffffff81c01d60 ffffffff810d9d1e
[    0.000000]  ffffffff81c01ff8 ffffffff81c00000 ffffffff81c01fe8 ffffffff824d3138
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff81747f7c>] dump_stack+0x54/0x74
[    0.000000]  [<ffffffff81383d27>] debug_locks_off+0x17/0x50
[    0.000000]  [<ffffffff810d9d1e>] check_usage+0x10e/0x550
[    0.000000]  [<ffffffff810170f4>] ? dump_trace+0x194/0x2f0
[    0.000000]  [<ffffffff810d6a54>] ? __bfs+0x24/0x240
[    0.000000]  [<ffffffff810da1af>] check_irq_usage+0x4f/0xc0
[    0.000000]  [<ffffffff810dd1ae>] __lock_acquire+0x1bce/0x2190
[    0.000000]  [<ffffffff810d80e8>] ? lockdep_init_map+0x68/0x6d0
[    0.000000]  [<ffffffff810de882>] lock_acquire+0xb2/0x160
[    0.000000]  [<ffffffff81392636>] ? irqsafe4_hard_wlock_231+0xc6/0x110
[    0.000000]  [<ffffffff81392570>] ? irqsafe4_soft_wlock_231+0xf0/0xf0
[    0.000000]  [<ffffffff81751676>] _raw_write_lock+0x46/0x80
[    0.000000]  [<ffffffff81392636>] ? irqsafe4_hard_wlock_231+0xc6/0x110
[    0.000000]  [<ffffffff81392636>] irqsafe4_hard_wlock_231+0xc6/0x110
[    0.000000]  [<ffffffff817481f5>] dotest+0x43/0x5a7
[    0.000000]  [<ffffffff81399d35>] locking_selftest+0x12e5/0x2100
[    0.000000]  [<ffffffff81f1aca9>] start_kernel+0x2d2/0x427
[    0.000000]  [<ffffffff81f1a120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff81f1a4c7>] x86_64_start_reservations+0x2a/0x2c
[    0.000000]  [<ffffffff81f1a5d6>] x86_64_start_kernel+0x10d/0x11c
[    0.000000] ### __debug_locks_off called!
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.6 #13
[    0.000000] Hardware name: Sony Corporation VGN-Z25TN_B/VAIO, BIOS R2140M3 08/26/2008
[    0.000000]  ffffffff81c15580 ffffffff81c01e78 ffffffff81747f7c ffffffff81cab058
[    0.000000]  ffffffff81c01e88 ffffffff81383d27 ffffffff81c01ed8 ffffffff810df539
[    0.000000]  0000000000000082 ffffffff81392636 0000000000000092 ffffffff81cab058
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff81747f7c>] dump_stack+0x54/0x74
[    0.000000]  [<ffffffff81383d27>] debug_locks_off+0x17/0x50
[    0.000000]  [<ffffffff810df539>] lock_acquired+0x2f9/0x4d0
[    0.000000]  [<ffffffff81392636>] ? irqsafe4_hard_wlock_231+0xc6/0x110
[    0.000000]  [<ffffffff81392570>] ? irqsafe4_soft_wlock_231+0xf0/0xf0
[    0.000000]  [<ffffffff817516a2>] _raw_write_lock+0x72/0x80
[    0.000000]  [<ffffffff81392636>] ? irqsafe4_hard_wlock_231+0xc6/0x110
[    0.000000]  [<ffffffff81392636>] irqsafe4_hard_wlock_231+0xc6/0x110
[    0.000000]  [<ffffffff817481f5>] dotest+0x43/0x5a7
[    0.000000]  [<ffffffff81399d35>] locking_selftest+0x12e5/0x2100
[    0.000000]  [<ffffffff81f1aca9>] start_kernel+0x2d2/0x427
[    0.000000]  [<ffffffff81f1a120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff81f1a4c7>] x86_64_start_reservations+0x2a/0x2c
[    0.000000]  [<ffffffff81f1a5d6>] x86_64_start_kernel+0x10d/0x11c
[    0.000000]   ok  |  ok  |
[    0.000000]     soft-safe-A + unsafe-B #2/231:### __debug_locks_off called!
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.6 #13
[    0.000000] Hardware name: Sony Corporation VGN-Z25TN_B/VAIO, BIOS R2140M3 08/26/2008
[    0.000000]  0000000000000006 ffffffff81c01c38 ffffffff81747f7c ffffffff81c15c98
[    0.000000]  ffffffff81c01c48 ffffffff81383d27 ffffffff81c01d60 ffffffff810d9d1e
[    0.000000]  ffffffff81c01cd8 0000000081c00000 ffffffff81c01fe8 0000000000000001
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff81747f7c>] dump_stack+0x54/0x74
[    0.000000]  [<ffffffff81383d27>] debug_locks_off+0x17/0x50
[    0.000000]  [<ffffffff810d9d1e>] check_usage+0x10e/0x550
[    0.000000]  [<ffffffff810d9ac2>] ? check_usage_backwards+0x72/0x1c0
[    0.000000]  [<ffffffff810d6a54>] ? __bfs+0x24/0x240
[    0.000000]  [<ffffffff810da1af>] check_irq_usage+0x4f/0xc0
[    0.000000]  [<ffffffff810dd1cd>] __lock_acquire+0x1bed/0x2190
[    0.000000]  [<ffffffff817511e7>] ? _raw_spin_unlock_irqrestore+0x67/0x70
[    0.000000]  [<ffffffff810c13b6>] ? vprintk_emit+0x1d6/0x630
[    0.000000]  [<ffffffff810de882>] lock_acquire+0xb2/0x160
[    0.000000]  [<ffffffff8138d6f8>] ? irqsafe4_soft_spin_231+0xa8/0xf0
[    0.000000]  [<ffffffff8138d650>] ? irqsafe4_soft_rlock_231+0xf0/0xf0
[    0.000000]  [<ffffffff81750e96>] _raw_spin_lock+0x46/0x80
[    0.000000]  [<ffffffff8138d6f8>] ? irqsafe4_soft_spin_231+0xa8/0xf0
[    0.000000]  [<ffffffff8138d6f8>] irqsafe4_soft_spin_231+0xa8/0xf0
[    0.000000]  [<ffffffff817481f5>] dotest+0x43/0x5a7
[    0.000000]  [<ffffffff81399d81>] locking_selftest+0x1331/0x2100
[    0.000000]  [<ffffffff81f1aca9>] start_kernel+0x2d2/0x427
[    0.000000]  [<ffffffff81f1a120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff81f1a4c7>] x86_64_start_reservations+0x2a/0x2c
[    0.000000]  [<ffffffff81f1a5d6>] x86_64_start_kernel+0x10d/0x11c
[    0.000000] ### __debug_locks_off called!
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.6 #13
[    0.000000] Hardware name: Sony Corporation VGN-Z25TN_B/VAIO, BIOS R2140M3 08/26/2008
[    0.000000]  ffffffff81c15580 ffffffff81c01e78 ffffffff81747f7c ffffffff81cab258
[    0.000000]  ffffffff81c01e88 ffffffff81383d27 ffffffff81c01ed8 ffffffff810df539
[    0.000000]  0000000000000282 ffffffff8138d6f8 0000000000000292 ffffffff81cab258
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff81747f7c>] dump_stack+0x54/0x74
[    0.000000]  [<ffffffff81383d27>] debug_locks_off+0x17/0x50
[    0.000000]  [<ffffffff810df539>] lock_acquired+0x2f9/0x4d0
[    0.000000]  [<ffffffff8138d6f8>] ? irqsafe4_soft_spin_231+0xa8/0xf0
[    0.000000]  [<ffffffff8138d650>] ? irqsafe4_soft_rlock_231+0xf0/0xf0
[    0.000000]  [<ffffffff81750ec2>] _raw_spin_lock+0x72/0x80
[    0.000000]  [<ffffffff8138d6f8>] ? irqsafe4_soft_spin_231+0xa8/0xf0
[    0.000000]  [<ffffffff8138d6f8>] irqsafe4_soft_spin_231+0xa8/0xf0
[    0.000000]  [<ffffffff817481f5>] dotest+0x43/0x5a7
[    0.000000]  [<ffffffff81399d81>] locking_selftest+0x1331/0x2100
[    0.000000]  [<ffffffff81f1aca9>] start_kernel+0x2d2/0x427
[    0.000000]  [<ffffffff81f1a120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff81f1a4c7>] x86_64_start_reservations+0x2a/0x2c
[    0.000000]  [<ffffffff81f1a5d6>] x86_64_start_kernel+0x10d/0x11c
[    0.000000]   ok  |### __debug_locks_off called!
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.6 #13
[    0.000000] Hardware name: Sony Corporation VGN-Z25TN_B/VAIO, BIOS R2140M3 08/26/2008
[    0.000000]  0000000000000006 ffffffff81c01c38 ffffffff81747f7c ffffffff81c15c98
[    0.000000]  ffffffff81c01c48 ffffffff81383d27 ffffffff81c01d60 ffffffff810d9d1e
[    0.000000]  ffffffff81c01cd8 0000000081c00000 ffffffff81c01fe8 0000000000000001
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff81747f7c>] dump_stack+0x54/0x74
[    0.000000]  [<ffffffff81383d27>] debug_locks_off+0x17/0x50
[    0.000000]  [<ffffffff810d9d1e>] check_usage+0x10e/0x550
[    0.000000]  [<ffffffff810d9ac2>] ? check_usage_backwards+0x72/0x1c0
[    0.000000]  [<ffffffff810d6a54>] ? __bfs+0x24/0x240
[    0.000000]  [<ffffffff810da1af>] check_irq_usage+0x4f/0xc0
[    0.000000]  [<ffffffff810dd1cd>] __lock_acquire+0x1bed/0x2190
[    0.000000]  [<ffffffff810d80e8>] ? lockdep_init_map+0x68/0x6d0
[    0.000000]  [<ffffffff810de882>] lock_acquire+0xb2/0x160
[    0.000000]  [<ffffffff81392528>] ? irqsafe4_soft_wlock_231+0xa8/0xf0
[    0.000000]  [<ffffffff81392480>] ? irqsafe4_hard_wlock_312+0x110/0x110
[    0.000000]  [<ffffffff81751676>] _raw_write_lock+0x46/0x80
[    0.000000]  [<ffffffff81392528>] ? irqsafe4_soft_wlock_231+0xa8/0xf0
[    0.000000]  [<ffffffff81392528>] irqsafe4_soft_wlock_231+0xa8/0xf0
[    0.000000]  [<ffffffff817481f5>] dotest+0x43/0x5a7
[    0.000000]  [<ffffffff81399d94>] locking_selftest+0x1344/0x2100
[    0.000000]  [<ffffffff81f1aca9>] start_kernel+0x2d2/0x427
[    0.000000]  [<ffffffff81f1a120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff81f1a4c7>] x86_64_start_reservations+0x2a/0x2c
[    0.000000]  [<ffffffff81f1a5d6>] x86_64_start_kernel+0x10d/0x11c
[    0.000000] ### __debug_locks_off called!
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.6 #13
[    0.000000] Hardware name: Sony Corporation VGN-Z25TN_B/VAIO, BIOS R2140M3 08/26/2008
[    0.000000]  ffffffff81c15580 ffffffff81c01e78 ffffffff81747f7c ffffffff81cab058
[    0.000000]  ffffffff81c01e88 ffffffff81383d27 ffffffff81c01ed8 ffffffff810df539
[    0.000000]  0000000000000282 ffffffff81392528 0000000000000292 ffffffff81cab058
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff81747f7c>] dump_stack+0x54/0x74
[    0.000000]  [<ffffffff81383d27>] debug_locks_off+0x17/0x50
[    0.000000]  [<ffffffff810df539>] lock_acquired+0x2f9/0x4d0
[    0.000000]  [<ffffffff81392528>] ? irqsafe4_soft_wlock_231+0xa8/0xf0
[    0.000000]  [<ffffffff81392480>] ? irqsafe4_hard_wlock_312+0x110/0x110
[    0.000000]  [<ffffffff817516a2>] _raw_write_lock+0x72/0x80
[    0.000000]  [<ffffffff81392528>] ? irqsafe4_soft_wlock_231+0xa8/0xf0
[    0.000000]  [<ffffffff81392528>] irqsafe4_soft_wlock_231+0xa8/0xf0
[    0.000000]  [<ffffffff817481f5>] dotest+0x43/0x5a7
[    0.000000]  [<ffffffff81399d94>] locking_selftest+0x1344/0x2100
[    0.000000]  [<ffffffff81f1aca9>] start_kernel+0x2d2/0x427
[    0.000000]  [<ffffffff81f1a120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff81f1a4c7>] x86_64_start_reservations+0x2a/0x2c
[    0.000000]  [<ffffffff81f1a5d6>] x86_64_start_kernel+0x10d/0x11c
[    0.000000]   ok  |  ok  |
[    0.000000]     hard-safe-A + unsafe-B #2/312:### __debug_locks_off called!
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.6 #13
[    0.000000] Hardware name: Sony Corporation VGN-Z25TN_B/VAIO, BIOS R2140M3 08/26/2008
[    0.000000]  0000000000000000 ffffffff81c01cb0 ffffffff81747f7c ffffffff81c15c98
[    0.000000]  ffffffff81c01cc0 ffffffff81383d27 ffffffff81c01d50 ffffffff810d9adf
[    0.000000]  0000000000000000 ffffffff8288dec0 ffffffff824d43a8 0000000081c01d60
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff81747f7c>] dump_stack+0x54/0x74
[    0.000000]  [<ffffffff81383d27>] debug_locks_off+0x17/0x50
[    0.000000]  [<ffffffff810d9adf>] check_usage_backwards+0x8f/0x1c0
[    0.000000]  [<ffffffff810da9c2>] mark_lock+0x412/0x820
[    0.000000]  [<ffffffff810d9a50>] ? check_usage_forwards+0x1c0/0x1c0
[    0.000000]  [<ffffffff810dbf68>] __lock_acquire+0x988/0x2190
[    0.000000]  [<ffffffff817511e7>] ? _raw_spin_unlock_irqrestore+0x67/0x70
[    0.000000]  [<ffffffff810c13b6>] ? vprintk_emit+0x1d6/0x630
[    0.000000]  [<ffffffff810de882>] lock_acquire+0xb2/0x160
[    0.000000]  [<ffffffff8138b72e>] ? irqsafe4_hard_spin_312+0xde/0x110
[    0.000000]  [<ffffffff8138b650>] ? irqsafe4_hard_rlock_312+0x110/0x110
[    0.000000]  [<ffffffff81750e96>] _raw_spin_lock+0x46/0x80
[    0.000000]  [<ffffffff8138b72e>] ? irqsafe4_hard_spin_312+0xde/0x110
[    0.000000]  [<ffffffff8138b72e>] irqsafe4_hard_spin_312+0xde/0x110
[    0.000000]  [<ffffffff817481f5>] dotest+0x43/0x5a7
[    0.000000]  [<ffffffff81399de0>] locking_selftest+0x1390/0x2100
[    0.000000]  [<ffffffff81f1aca9>] start_kernel+0x2d2/0x427
[    0.000000]  [<ffffffff81f1a120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff81f1a4c7>] x86_64_start_reservations+0x2a/0x2c
[    0.000000]  [<ffffffff81f1a5d6>] x86_64_start_kernel+0x10d/0x11c
[    0.000000] ### __debug_locks_off called!
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.6 #13
[    0.000000] Hardware name: Sony Corporation VGN-Z25TN_B/VAIO, BIOS R2140M3 08/26/2008
[    0.000000]  ffffffff81c15580 ffffffff81c01e78 ffffffff81747f7c ffffffff81cab258
[    0.000000]  ffffffff81c01e88 ffffffff81383d27 ffffffff81c01ed8 ffffffff810df595
[    0.000000]  0000000000000282 ffffffff8138b72e 0000000000000292 ffffffff81cab258
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff81747f7c>] dump_stack+0x54/0x74
[    0.000000]  [<ffffffff81383d27>] debug_locks_off+0x17/0x50
[    0.000000]  [<ffffffff810df595>] lock_acquired+0x355/0x4d0
[    0.000000]  [<ffffffff8138b72e>] ? irqsafe4_hard_spin_312+0xde/0x110
[    0.000000]  [<ffffffff8138b650>] ? irqsafe4_hard_rlock_312+0x110/0x110
[    0.000000]  [<ffffffff81750ec2>] _raw_spin_lock+0x72/0x80
[    0.000000]  [<ffffffff8138b72e>] ? irqsafe4_hard_spin_312+0xde/0x110
[    0.000000]  [<ffffffff8138b72e>] irqsafe4_hard_spin_312+0xde/0x110
[    0.000000]  [<ffffffff817481f5>] dotest+0x43/0x5a7
[    0.000000]  [<ffffffff81399de0>] locking_selftest+0x1390/0x2100
[    0.000000]  [<ffffffff81f1aca9>] start_kernel+0x2d2/0x427
[    0.000000]  [<ffffffff81f1a120>] ? early_idt_handlers+0x120/0x120
[    0.000000]  [<ffffffff81f1a4c7>] 
[    0.000000]  [<ffffffff81f1a5d6>] x86_64_start_kernel+0x10d/0x11c
[    0.000000]   ok  |
[    0.000000] -------------------------------------------------------
[    0.000000] Good, all 253 testcases passed! |
[    0.000000] ---------------------------------
[    0.000000] hpet clockevent registered

最佳答案

启用锁统计

首先请确保启用锁统计信息收集。来自 Documentation/locking/lockstat.txt :

  • CONFIGURATION

Lock statistics are enabled via CONFIG_LOCK_STAT.

  • USAGE

Enable collection of statistics:

# echo 1 >/proc/sys/kernel/lock_stat

Disable collection of statistics:

# echo 0 >/proc/sys/kernel/lock_stat

Look at the current lock statistics:

( line numbers not part of actual output, done for clarity in the explanation below )

# less /proc/lock_stat

因此，请务必首先启用锁统计信息的收集。

检查内核日志中的 lockdep 警告

现在，让我们看一下打印警告消息的代码:

kernel/locking/lockdep_proc.c : seq_header() :

if (unlikely(!debug_locks))
    seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");

这个debug_locks变量被 debug_locks_off() 设置为 0(禁用)函数，而该函数又可以从很多地方调用。我们看一下这个变量定义的地方:

lib/debug_locks.c :

/*
 * We want to turn all lock-debugging facilities on/off at once,
 * via a global flag. The reason is that once a single bug has been
 * detected and reported, there might be cascade of followup bugs
 * that would just muddy the log. So we report the first one and
 * shut up after that.
 */
int debug_locks = 1;
EXPORT_SYMBOL_GPL(debug_locks);

对该变量的评论解释了您看到该警告的原因。

因此请检查您的内核日志(通过 dmesg 命令)以了解 lockdep 实际发现的错误机制。您可能会找到一个，这将解释为什么锁定调试被禁用。

更新

关于此消息:

[ 0.084000] SMP alternatives: lockdep: fixing up alternatives

这似乎与您的实际问题无关。此消息由下一个代码打印:

arch/x86/kernel/alternative.c : alternatives_enable_smp() :

#ifdef CONFIG_LOCKDEP
   /*
    * Older binutils section handling bug prevented
    * alternatives-replacement from working reliably.
    *
    * If this still occurs then you should see a hang
    * or crash shortly after this line:
    */
   pr_info("lockdep: fixing up alternatives\n");
#endif

此代码是旧的且过时的，并且通过此提交将其删除到较新的内核版本中:

lockdep, x86/alternatives: Drop ancient lockdep fixup message

所以我认为还有其他原因导致禁用锁定统计信息的收集。但很难说清楚到底是什么。我唯一能想到的就是修改内核，以便您可以看到导致禁用锁调试的原因，重建内核并查看内核日志以找出调用锁调试禁用的位置。

所以，如果您能做到这一点，请修改 __debug_locks_off()功能如下:

static inline int __debug_locks_off(void)
{
    /* ---- Add this code ---- */
    pr_err("### __debug_locks_off() called!\n");
    dump_stack();
    /* ----------------------- */

    return xchg(&debug_locks, 0);
}

此外，添加#include <linux/printk.h>以防万一，在该文件的顶部添加一行。

然后重建你的内核，运行它并提供整个dmesg输出。它应该足以告诉它在哪里被禁用。

更新2

正如我从您提供的回溯中看到的，所有 dump_stack()调用(您添加到 __debug_locks_off() 函数)——它们从 locking_selftest() 调用函数，这又只是一些单元测试例程。我们来看一下:locking_selftest() 。这里需要注意的是这段代码:

} else {
    printk("-------------------------------------------------------\n");
    printk("Good, all %3d testcases passed! |\n",
        testcase_successes);
    printk("---------------------------------\n");
    debug_locks = 1;
}

所以你可以看到，在你的情况下，你有 debug_locks locking_selftest() 末尾启用变量(“on”) 。考虑到您提供的所有消息实际上都是从locking_selftest()触发的我可以说这些消息不会导致您的问题(已禁用 debug_locks 变量)。

所以你仍然需要弄清楚，在哪里以及为什么(在你的情况下)这个 debug_locks变量被禁用。让我们从这里开始:请分享完整的dmesg与我们一起输出(您可以使用一些pastebin服务，只需将链接添加到您的问题或作为新评论)。你可能忽略了一些__debug_locks_off()调用您的dmesg实际相关的输出(不是从该自测试例程中调用的)。

关于linux - 在linux内核中查找锁统计信息，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32443393/

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