[PATCH AUTOSEL for 4.4 162/162] irqchip/gic-v3: Change pr_debug message to pr_devel

2018-04-08 Thread Sasha Levin 
From: Mark Salter 

[ Upstream commit b6dd4d83dc2f78cebc9a7e6e7e4bc2be4d29b94d ]

The pr_debug() in gic-v3 gic_send_sgi() can trigger a circular locking
warning:

 GICv3: CPU10: ICC_SGI1R_EL1 5000400
 ==
 WARNING: possible circular locking dependency detected
 4.15.0+ #1 Tainted: GW
 --
 dynamic_debug01/1873 is trying to acquire lock:
  ((console_sem).lock){-...}, at: [<99c891ec>] down_trylock+0x20/0x4c

 but task is already holding lock:
  (>lock){-.-.}, at: [<842e1587>] __task_rq_lock+0x54/0xdc

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #2 (>lock){-.-.}:
__lock_acquire+0x3b4/0x6e0
lock_acquire+0xf4/0x2a8
_raw_spin_lock+0x4c/0x60
task_fork_fair+0x3c/0x148
sched_fork+0x10c/0x214
copy_process.isra.32.part.33+0x4e8/0x14f0
_do_fork+0xe8/0x78c
kernel_thread+0x48/0x54
rest_init+0x34/0x2a4
start_kernel+0x45c/0x488

 -> #1 (>pi_lock){-.-.}:
__lock_acquire+0x3b4/0x6e0
lock_acquire+0xf4/0x2a8
_raw_spin_lock_irqsave+0x58/0x70
try_to_wake_up+0x48/0x600
wake_up_process+0x28/0x34
__up.isra.0+0x60/0x6c
up+0x60/0x68
__up_console_sem+0x4c/0x7c
console_unlock+0x328/0x634
vprintk_emit+0x25c/0x390
dev_vprintk_emit+0xc4/0x1fc
dev_printk_emit+0x88/0xa8
__dev_printk+0x58/0x9c
_dev_info+0x84/0xa8
usb_new_device+0x100/0x474
hub_port_connect+0x280/0x92c
hub_event+0x740/0xa84
process_one_work+0x240/0x70c
worker_thread+0x60/0x400
kthread+0x110/0x13c
ret_from_fork+0x10/0x18

 -> #0 ((console_sem).lock){-...}:
validate_chain.isra.34+0x6e4/0xa20
__lock_acquire+0x3b4/0x6e0
lock_acquire+0xf4/0x2a8
_raw_spin_lock_irqsave+0x58/0x70
down_trylock+0x20/0x4c
__down_trylock_console_sem+0x3c/0x9c
console_trylock+0x20/0xb0
vprintk_emit+0x254/0x390
vprintk_default+0x58/0x90
vprintk_func+0xbc/0x164
printk+0x80/0xa0
__dynamic_pr_debug+0x84/0xac
gic_raise_softirq+0x184/0x18c
smp_cross_call+0xac/0x218
smp_send_reschedule+0x3c/0x48
resched_curr+0x60/0x9c
check_preempt_curr+0x70/0xdc
wake_up_new_task+0x310/0x470
_do_fork+0x188/0x78c
SyS_clone+0x44/0x50
__sys_trace_return+0x0/0x4

 other info that might help us debug this:

 Chain exists of:
   (console_sem).lock --> >pi_lock --> >lock

  Possible unsafe locking scenario:

CPU0CPU1

   lock(>lock);
lock(>pi_lock);
lock(>lock);
   lock((console_sem).lock);

  *** DEADLOCK ***

 2 locks held by dynamic_debug01/1873:
  #0:  (>pi_lock){-.-.}, at: [<1366df53>] wake_up_new_task+0x40/0x470
  #1:  (>lock){-.-.}, at: [<842e1587>] __task_rq_lock+0x54/0xdc

 stack backtrace:
 CPU: 10 PID: 1873 Comm: dynamic_debug01 Tainted: GW4.15.0+ #1
 Hardware name: GIGABYTE R120-T34-00/MT30-GS2-00, BIOS T48 10/02/2017
 Call trace:
  dump_backtrace+0x0/0x188
  show_stack+0x24/0x2c
  dump_stack+0xa4/0xe0
  print_circular_bug.isra.31+0x29c/0x2b8
  check_prev_add.constprop.39+0x6c8/0x6dc
  validate_chain.isra.34+0x6e4/0xa20
  __lock_acquire+0x3b4/0x6e0
  lock_acquire+0xf4/0x2a8
  _raw_spin_lock_irqsave+0x58/0x70
  down_trylock+0x20/0x4c
  __down_trylock_console_sem+0x3c/0x9c
  console_trylock+0x20/0xb0
  vprintk_emit+0x254/0x390
  vprintk_default+0x58/0x90
  vprintk_func+0xbc/0x164
  printk+0x80/0xa0
  __dynamic_pr_debug+0x84/0xac
  gic_raise_softirq+0x184/0x18c
  smp_cross_call+0xac/0x218
  smp_send_reschedule+0x3c/0x48
  resched_curr+0x60/0x9c
  check_preempt_curr+0x70/0xdc
  wake_up_new_task+0x310/0x470
  _do_fork+0x188/0x78c
  SyS_clone+0x44/0x50
  __sys_trace_return+0x0/0x4
 GICv3: CPU0: ICC_SGI1R_EL1 12000

This could be fixed with printk_deferred() but that might lessen its
usefulness for debugging. So change it to pr_devel to keep it out of
production kernels. Developers working on gic-v3 can enable it as
needed in their kernels.

Signed-off-by: Mark Salter 
Signed-off-by: Marc Zyngier 
Signed-off-by: Sasha Levin 
---
 drivers/irqchip/irq-gic-v3.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index eed31f9bee05..cb0d0caadc3f 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -589,7 +589,7 @@ static void gic_send_sgi(u64 cluster_id, u16 tlist, 
unsigned int irq)
   MPIDR_TO_SGI_AFFINITY(cluster_id, 1) |
   tlist << ICC_SGI1R_TARGET_LIST_SHIFT);

[PATCH AUTOSEL for 4.4 162/162] irqchip/gic-v3: Change pr_debug message to pr_devel

2018-04-08 Thread Sasha Levin 
From: Mark Salter 

[ Upstream commit b6dd4d83dc2f78cebc9a7e6e7e4bc2be4d29b94d ]

The pr_debug() in gic-v3 gic_send_sgi() can trigger a circular locking
warning:

 GICv3: CPU10: ICC_SGI1R_EL1 5000400
 ==
 WARNING: possible circular locking dependency detected
 4.15.0+ #1 Tainted: GW
 --
 dynamic_debug01/1873 is trying to acquire lock:
  ((console_sem).lock){-...}, at: [<99c891ec>] down_trylock+0x20/0x4c

 but task is already holding lock:
  (>lock){-.-.}, at: [<842e1587>] __task_rq_lock+0x54/0xdc

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #2 (>lock){-.-.}:
__lock_acquire+0x3b4/0x6e0
lock_acquire+0xf4/0x2a8
_raw_spin_lock+0x4c/0x60
task_fork_fair+0x3c/0x148
sched_fork+0x10c/0x214
copy_process.isra.32.part.33+0x4e8/0x14f0
_do_fork+0xe8/0x78c
kernel_thread+0x48/0x54
rest_init+0x34/0x2a4
start_kernel+0x45c/0x488

 -> #1 (>pi_lock){-.-.}:
__lock_acquire+0x3b4/0x6e0
lock_acquire+0xf4/0x2a8
_raw_spin_lock_irqsave+0x58/0x70
try_to_wake_up+0x48/0x600
wake_up_process+0x28/0x34
__up.isra.0+0x60/0x6c
up+0x60/0x68
__up_console_sem+0x4c/0x7c
console_unlock+0x328/0x634
vprintk_emit+0x25c/0x390
dev_vprintk_emit+0xc4/0x1fc
dev_printk_emit+0x88/0xa8
__dev_printk+0x58/0x9c
_dev_info+0x84/0xa8
usb_new_device+0x100/0x474
hub_port_connect+0x280/0x92c
hub_event+0x740/0xa84
process_one_work+0x240/0x70c
worker_thread+0x60/0x400
kthread+0x110/0x13c
ret_from_fork+0x10/0x18

 -> #0 ((console_sem).lock){-...}:
validate_chain.isra.34+0x6e4/0xa20
__lock_acquire+0x3b4/0x6e0
lock_acquire+0xf4/0x2a8
_raw_spin_lock_irqsave+0x58/0x70
down_trylock+0x20/0x4c
__down_trylock_console_sem+0x3c/0x9c
console_trylock+0x20/0xb0
vprintk_emit+0x254/0x390
vprintk_default+0x58/0x90
vprintk_func+0xbc/0x164
printk+0x80/0xa0
__dynamic_pr_debug+0x84/0xac
gic_raise_softirq+0x184/0x18c
smp_cross_call+0xac/0x218
smp_send_reschedule+0x3c/0x48
resched_curr+0x60/0x9c
check_preempt_curr+0x70/0xdc
wake_up_new_task+0x310/0x470
_do_fork+0x188/0x78c
SyS_clone+0x44/0x50
__sys_trace_return+0x0/0x4

 other info that might help us debug this:

 Chain exists of:
   (console_sem).lock --> >pi_lock --> >lock

  Possible unsafe locking scenario:

CPU0CPU1

   lock(>lock);
lock(>pi_lock);
lock(>lock);
   lock((console_sem).lock);

  *** DEADLOCK ***

 2 locks held by dynamic_debug01/1873:
  #0:  (>pi_lock){-.-.}, at: [<1366df53>] wake_up_new_task+0x40/0x470
  #1:  (>lock){-.-.}, at: [<842e1587>] __task_rq_lock+0x54/0xdc

 stack backtrace:
 CPU: 10 PID: 1873 Comm: dynamic_debug01 Tainted: GW4.15.0+ #1
 Hardware name: GIGABYTE R120-T34-00/MT30-GS2-00, BIOS T48 10/02/2017
 Call trace:
  dump_backtrace+0x0/0x188
  show_stack+0x24/0x2c
  dump_stack+0xa4/0xe0
  print_circular_bug.isra.31+0x29c/0x2b8
  check_prev_add.constprop.39+0x6c8/0x6dc
  validate_chain.isra.34+0x6e4/0xa20
  __lock_acquire+0x3b4/0x6e0
  lock_acquire+0xf4/0x2a8
  _raw_spin_lock_irqsave+0x58/0x70
  down_trylock+0x20/0x4c
  __down_trylock_console_sem+0x3c/0x9c
  console_trylock+0x20/0xb0
  vprintk_emit+0x254/0x390
  vprintk_default+0x58/0x90
  vprintk_func+0xbc/0x164
  printk+0x80/0xa0
  __dynamic_pr_debug+0x84/0xac
  gic_raise_softirq+0x184/0x18c
  smp_cross_call+0xac/0x218
  smp_send_reschedule+0x3c/0x48
  resched_curr+0x60/0x9c
  check_preempt_curr+0x70/0xdc
  wake_up_new_task+0x310/0x470
  _do_fork+0x188/0x78c
  SyS_clone+0x44/0x50
  __sys_trace_return+0x0/0x4
 GICv3: CPU0: ICC_SGI1R_EL1 12000

This could be fixed with printk_deferred() but that might lessen its
usefulness for debugging. So change it to pr_devel to keep it out of
production kernels. Developers working on gic-v3 can enable it as
needed in their kernels.

Signed-off-by: Mark Salter 
Signed-off-by: Marc Zyngier 
Signed-off-by: Sasha Levin 
---
 drivers/irqchip/irq-gic-v3.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index eed31f9bee05..cb0d0caadc3f 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -589,7 +589,7 @@ static void gic_send_sgi(u64 cluster_id, u16 tlist, 
unsigned int irq)
   MPIDR_TO_SGI_AFFINITY(cluster_id, 1) |
   tlist << ICC_SGI1R_TARGET_LIST_SHIFT);
 
-   pr_debug("CPU%d: ICC_SGI1R_EL1 %llx\n", smp_processor_id(), val);
+