linux/arch/powerpc/platforms/powernv
Alistair Popple 036592fbbe powerpc/opal-irqchip: Fix deadlock introduced by "Fix double endian conversion"
Commit 25642e1459 ("powerpc/opal-irqchip: Fix double endian
conversion") fixed an endian bug by calling opal_handle_events() in
opal_event_unmask().

However this introduced a deadlock if we find an event is active
during unmasking and call opal_handle_events() again. The bad call
sequence is:

  opal_interrupt()
  -> opal_handle_events()
     -> generic_handle_irq()
        -> handle_level_irq()
           -> raw_spin_lock(&desc->lock)
              handle_irq_event(desc)
              unmask_irq(desc)
              -> opal_event_unmask()
                 -> opal_handle_events()
                    -> generic_handle_irq()
                       -> handle_level_irq()
                          -> raw_spin_lock(&desc->lock)	(BOOM)

When generating multiple opal events in quick succession this would lead
to the following stall warnings:

EEH: Fenced PHB#0 detected, location: U78C9.001.WZS09XA-P1-C32
INFO: rcu_sched detected stalls on CPUs/tasks:

         12-...: (1 GPs behind) idle=68f/140000000000001/0 softirq=860/861 fqs=2065
         15-...: (1 GPs behind) idle=be5/140000000000001/0 softirq=1142/1143 fqs=2065
         (detected by 13, t=2102 jiffies, g=1325, c=1324, q=602)
NMI watchdog: BUG: soft lockup - CPU#18 stuck for 22s! [irqbalance:2696]
INFO: rcu_sched detected stalls on CPUs/tasks:
         12-...: (1 GPs behind) idle=68f/140000000000001/0 softirq=860/861 fqs=8371
         15-...: (1 GPs behind) idle=be5/140000000000001/0 softirq=1142/1143 fqs=8371
         (detected by 20, t=8407 jiffies, g=1325, c=1324, q=1290)

This patch corrects the problem by queuing the work if an event is
active during unmasking, which is similar to the pre-endian fix
behaviour.

Fixes: 25642e1459 ("powerpc/opal-irqchip: Fix double endian conversion")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Reported-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-12-18 22:24:15 +11:00
..
eeh-powernv.c powerpc/eeh: Fix recursive fenced PHB on Broadcom shiner adapter 2015-10-21 20:42:16 +11:00
idle.c powerpc/powernv: pnv_init_idle_states() should only run on powernv 2015-06-15 16:45:12 +10:00
Kconfig powerpc/powernv: Add opal-prd channel 2015-06-05 08:32:21 +10:00
Makefile powerpc/powernv: Add opal-prd channel 2015-06-05 08:32:21 +10:00
opal-async.c powerpc/powernv: Reorder OPAL subsystem initialisation 2015-05-22 15:14:37 +10:00
opal-dump.c powernv/opal-dump: Convert to irq domain 2015-05-22 15:14:38 +10:00
opal-elog.c powerpc/powernv: Fix opal-elog interrupt handler 2015-07-06 20:24:36 +10:00
opal-flash.c powerpc/powernv: Add interfaces for flash device access 2015-04-11 20:49:21 +10:00
opal-hmi.c powerpc/powernv: Invoke opal_cec_reboot2() on unrecoverable HMI. 2015-08-06 15:10:19 +10:00
opal-irqchip.c powerpc/opal-irqchip: Fix deadlock introduced by "Fix double endian conversion" 2015-12-18 22:24:15 +11:00
opal-lpc.c powerpc/powernv: Properly fix LPC debugfs endianness 2014-10-31 17:09:04 +11:00
opal-memory-errors.c powerpc/powernv: Reorder OPAL subsystem initialisation 2015-05-22 15:14:37 +10:00
opal-msglog.c powerpc/powernv: Fix reading of OPAL msglog 2014-06-11 17:03:36 +10:00
opal-nvram.c powerpc/powernv: Add pstore support on powernv 2015-03-23 14:06:10 +11:00
opal-power.c powerpc/powernv: Add poweroff (EPOW, DPO) events support for PowerNV platform 2015-07-16 13:34:36 +10:00
opal-prd.c powerpc/powernv: Fix vma page prot flags in opal-prd driver 2015-07-06 12:06:42 +10:00
opal-rtc.c rtc/tpo: Driver to support rtc and wakeup on PowerNV platform 2014-11-17 18:04:01 +11:00
opal-sensor.c powerpc/powernv: Reorder OPAL subsystem initialisation 2015-05-22 15:14:37 +10:00
opal-sysparam.c powerpc/powernv: convert OPAL codes returned by sysparam calls 2015-06-04 22:27:56 +10:00
opal-tracepoints.c powerpc: Replace __get_cpu_var uses 2014-11-03 12:12:32 +11:00
opal-wrappers.S powerpc/powernv: Add OPAL interfaces for accessing and modifying system LED states 2015-08-20 18:19:07 +10:00
opal-xscom.c powerpc/powernv: Switch powernv drivers to use machine_xxx_initcall() 2014-07-28 14:11:26 +10:00
opal.c powerpc/powernv: pr_warn_once on unsupported OPAL_MSG type 2015-12-17 20:42:13 +11:00
pci-ioda.c powerpc/powernv/pci-ioda: fix kdump with non-power-of-2 crashkernel= 2015-09-07 20:14:18 +10:00
pci-p5ioc2.c vfio: powerpc/spapr: powerpc/powernv/ioda: Define and implement DMA windows API 2015-06-11 15:16:52 +10:00
pci.c powerpc/MSI: Fix race condition in tearing down MSI interrupts 2015-09-10 17:27:08 +10:00
pci.h powerpc/powernv: move dma_get_required_mask from pnv_phb to pci_controller_ops 2015-08-18 19:32:11 +10:00
powernv.h powerpc/powernv: move dma_get_required_mask from pnv_phb to pci_controller_ops 2015-08-18 19:32:11 +10:00
rng.c powerpc: Use hardware RNG for arch_get_random_seed_* not arch_get_random_* 2015-07-23 19:52:03 +10:00
setup.c powerpc/kexec: Wait 1s for secondaries to enter OPAL 2015-10-06 21:57:42 +11:00
smp.c powerpc/powernv: Handle irq_happened flag correctly in off-line loop 2015-10-21 20:52:49 +11:00
subcore-asm.S powerpc/powernv: Add support for POWER8 split core on powernv 2014-05-28 13:35:37 +10:00
subcore.c powerpc: Add an inline function to update POWER8 HID0 2015-08-14 15:58:28 +10:00
subcore.h powernv/powerpc: Add winkle support for offline cpus 2014-12-15 10:46:41 +11:00