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Ingo Molnar authored
Fix a potential deadlock scenario introduced by io_apic.c's new vector_lock on i386 and x86_64. Found by the locking correctness validator. The patch was boot-tested on x86. For details of the deadlock scenario, see the validator output: ====================================================== [ BUG: hard-safe -> hard-unsafe lock order detected! ] ------------------------------------------------------ idle/1 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: (msi_lock){....}, at: [<c04ff8d2>] startup_msi_irq_wo_maskbit+0x10/0x35 and this task is already holding: (&irq_desc[i].lock){++..}, at: [<c015b924>] probe_irq_on+0x36/0x107 which would create a new lock dependency: (&irq_desc[i].lock){++..} -> (msi_lock){....} but this new dependency connects a hard-irq-safe lock: (&irq_desc[i].lock){++..} ... which became hard-irq-safe at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10485e9>] _spin_lock+0x21/0x2f [<c015aff5>] __do_IRQ+0x3d/0x113 [<c01062d3>] do_IRQ+0x8c/0xad to a hard-irq-unsafe lock: (vector_lock){--..} ... which became hard-irq-unsafe at: ... [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10485e9>] _spin_lock+0x21/0x2f [<c011b5e8>] assign_irq_vector+0x34/0xc8 [<c1aa82fa>] setup_IO_APIC+0x45a/0xcff [<c1aa56e3>] smp_prepare_cpus+0x5ea/0x8aa [<c010033f>] init+0x32/0x2cb [<c0102005>] kernel_thread_helper+0x5/0xb which could potentially lead to deadlocks! other info that might help us debug this: 3 locks held by idle/1: #0: (port_mutex){--..}, at: [<c067070d>] uart_add_one_port+0x61/0x289 #1: (&state->mutex){--..}, at: [<c067071f>] uart_add_one_port+0x73/0x289 #2: (&irq_desc[i].lock){++..}, at: [<c015b924>] probe_irq_on+0x36/0x107 the hard-irq-safe lock's dependencies: -> (&irq_desc[i].lock){++..} ops: 9861 { initial-use at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c015b415>] setup_irq+0x9b/0x14d [<c1aaa4c4>] time_init_hook+0xf/0x11 [<c1a9f320>] time_init+0x44/0x46 [<c1a9955f>] start_kernel+0x191/0x38f [<c0100210>] 0xc0100210 in-hardirq-W at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10485e9>] _spin_lock+0x21/0x2f [<c015aff5>] __do_IRQ+0x3d/0x113 [<c01062d3>] do_IRQ+0x8c/0xad in-softirq-W at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10485e9>] _spin_lock+0x21/0x2f [<c015aff5>] __do_IRQ+0x3d/0x113 [<c01062d3>] do_IRQ+0x8c/0xad } ... key at: [<c1ea31e0>] irq_desc_lock_type+0x0/0x20 -> (i8259A_lock){++..} ops: 5149 { initial-use at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c0108090>] init_8259A+0x11/0x8f [<c1aa0d22>] init_ISA_irqs+0x12/0x4d [<c1aaa4f0>] pre_intr_init_hook+0x8/0xa [<c1aa0cb9>] init_IRQ+0xe/0x65 [<c1a99546>] start_kernel+0x178/0x38f [<c0100210>] 0xc0100210 in-hardirq-W at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c0107fb0>] mask_and_ack_8259A+0x1b/0xcc [<c015b007>] __do_IRQ+0x4f/0x113 [<c01062d3>] do_IRQ+0x8c/0xad in-softirq-W at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c0107fb0>] mask_and_ack_8259A+0x1b/0xcc [<c015b007>] __do_IRQ+0x4f/0x113 [<c01062d3>] do_IRQ+0x8c/0xad } ... key at: [<c142f174>] i8259A_lock+0x14/0x40 ... acquired at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c0107eb2>] enable_8259A_irq+0x10/0x47 [<c0107f12>] startup_8259A_irq+0x8/0xc [<c015b45e>] setup_irq+0xe4/0x14d [<c1aaa4c4>] time_init_hook+0xf/0x11 [<c1a9f320>] time_init+0x44/0x46 [<c1a9955f>] start_kernel+0x191/0x38f [<c0100210>] 0xc0100210 -> (ioapic_lock){+...} ops: 122 { initial-use at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c1aa71db>] io_apic_get_version+0x16/0x55 [<c1aa5c73>] mp_register_ioapic+0xc6/0x127 [<c1aa382e>] acpi_parse_ioapic+0x2d/0x39 [<c1abe031>] acpi_table_parse_madt_family+0xb4/0x100 [<c1abe093>] acpi_table_parse_madt+0x16/0x18 [<c1aa3c8a>] acpi_boot_init+0x132/0x251 [<c1aa08ea>] setup_arch+0xd36/0xe37 [<c1a99434>] start_kernel+0x66/0x38f [<c0100210>] 0xc0100210 in-hardirq-W at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c011bce1>] mask_IO_APIC_irq+0x11/0x31 [<c011c5cc>] ack_edge_ioapic_vector+0x31/0x41 [<c015b007>] __do_IRQ+0x4f/0x113 [<c01062d3>] do_IRQ+0x8c/0xad } ... key at: [<c1432514>] ioapic_lock+0x14/0x3c -> (i8259A_lock){++..} ops: 5149 { initial-use at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c0108090>] init_8259A+0x11/0x8f [<c1aa0d22>] init_ISA_irqs+0x12/0x4d [<c1aaa4f0>] pre_intr_init_hook+0x8/0xa [<c1aa0cb9>] init_IRQ+0xe/0x65 [<c1a99546>] start_kernel+0x178/0x38f [<c0100210>] 0xc0100210 in-hardirq-W at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c0107fb0>] mask_and_ack_8259A+0x1b/0xcc [<c015b007>] __do_IRQ+0x4f/0x113 [<c01062d3>] do_IRQ+0x8c/0xad in-softirq-W at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c0107fb0>] mask_and_ack_8259A+0x1b/0xcc [<c015b007>] __do_IRQ+0x4f/0x113 [<c01062d3>] do_IRQ+0x8c/0xad } ... key at: [<c142f174>] i8259A_lock+0x14/0x40 ... acquired at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c0107e6b>] disable_8259A_irq+0x10/0x47 [<c011bdbd>] startup_edge_ioapic_vector+0x31/0x58 [<c015b45e>] setup_irq+0xe4/0x14d [<c015b5a1>] request_irq+0xda/0xf9 [<c1ac983a>] rtc_init+0x6a/0x1a7 [<c0100457>] init+0x14a/0x2cb [<c0102005>] kernel_thread_helper+0x5/0xb ... acquired at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c011bce1>] mask_IO_APIC_irq+0x11/0x31 [<c011c5cc>] ack_edge_ioapic_vector+0x31/0x41 [<c015b007>] __do_IRQ+0x4f/0x113 [<c01062d3>] do_IRQ+0x8c/0xad the hard-irq-unsafe lock's dependencies: -> (vector_lock){--..} ops: 31 { initial-use at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10485e9>] _spin_lock+0x21/0x2f [<c011b5e8>] assign_irq_vector+0x34/0xc8 [<c1aa82fa>] setup_IO_APIC+0x45a/0xcff [<c1aa56e3>] smp_prepare_cpus+0x5ea/0x8aa [<c010033f>] init+0x32/0x2cb [<c0102005>] kernel_thread_helper+0x5/0xb softirq-on-W at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10485e9>] _spin_lock+0x21/0x2f [<c011b5e8>] assign_irq_vector+0x34/0xc8 [<c1aa82fa>] setup_IO_APIC+0x45a/0xcff [<c1aa56e3>] smp_prepare_cpus+0x5ea/0x8aa [<c010033f>] init+0x32/0x2cb [<c0102005>] kernel_thread_helper+0x5/0xb hardirq-on-W at: [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10485e9>] _spin_lock+0x21/0x2f [<c011b5e8>] assign_irq_vector+0x34/0xc8 [<c1aa82fa>] setup_IO_APIC+0x45a/0xcff [<c1aa56e3>] smp_prepare_cpus+0x5ea/0x8aa [<c010033f>] init+0x32/0x2cb [<c0102005>] kernel_thread_helper+0x5/0xb } ... key at: [<c1432574>] vector_lock+0x14/0x3c stack backtrace: [<c0104f36>] show_trace+0xd/0xf [<c010543e>] dump_stack+0x17/0x19 [<c0144e34>] check_usage+0x1f6/0x203 [<c0146395>] __lockdep_acquire+0x8c2/0xaa5 [<c01468c4>] lockdep_acquire+0x68/0x84 [<c10487f4>] _spin_lock_irqsave+0x2a/0x3a [<c04ff8d2>] startup_msi_irq_wo_maskbit+0x10/0x35 [<c015b932>] probe_irq_on+0x44/0x107 [<c0673d58>] serial8250_config_port+0x84b/0x986 [<c06707b1>] uart_add_one_port+0x105/0x289 [<c1ace54b>] serial8250_init+0xc3/0x10a [<c0100457>] init+0x14a/0x2cb [<c0102005>] kernel_thread_helper+0x5/0xb Signed-off-by:Ingo Molnar <mingo@elte.hu> Cc: Jan Beulich <jbeulich@novell.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Andi Kleen <ak@suse.de> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
26a3c49c
