* [v3 PATCH] arm64: replace read_lock to rcu lock in call_break_hook
@ 2015-10-05 21:32 ` Yang Shi
0 siblings, 0 replies; 8+ messages in thread
From: Yang Shi @ 2015-10-05 21:32 UTC (permalink / raw)
To: rostedt, catalin.marinas, will.deacon, paulmck, dave.long, panand
Cc: linux-kernel, linux-rt-users, linux-arm-kernel, linaro-kernel, yang.shi
BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
in_atomic(): 0, irqs_disabled(): 128, pid: 342, name: perf
1 lock held by perf/342:
#0: (break_hook_lock){+.+...}, at: [<ffffffc0000851ac>] call_break_hook+0x34/0xd0
irq event stamp: 62224
hardirqs last enabled at (62223): [<ffffffc00010b7bc>] __call_rcu.constprop.59+0x104/0x270
hardirqs last disabled at (62224): [<ffffffc0000fbe20>] vprintk_emit+0x68/0x640
softirqs last enabled at (0): [<ffffffc000097928>] copy_process.part.8+0x428/0x17f8
softirqs last disabled at (0): [< (null)>] (null)
CPU: 0 PID: 342 Comm: perf Not tainted 4.1.6-rt5 #4
Hardware name: linux,dummy-virt (DT)
Call trace:
[<ffffffc000089968>] dump_backtrace+0x0/0x128
[<ffffffc000089ab0>] show_stack+0x20/0x30
[<ffffffc0007030d0>] dump_stack+0x7c/0xa0
[<ffffffc0000c878c>] ___might_sleep+0x174/0x260
[<ffffffc000708ac8>] __rt_spin_lock+0x28/0x40
[<ffffffc000708db0>] rt_read_lock+0x60/0x80
[<ffffffc0000851a8>] call_break_hook+0x30/0xd0
[<ffffffc000085a70>] brk_handler+0x30/0x98
[<ffffffc000082248>] do_debug_exception+0x50/0xb8
Exception stack(0xffffffc00514fe30 to 0xffffffc00514ff50)
fe20: 00000000 00000000 c1594680 0000007f
fe40: ffffffff ffffffff 92063940 0000007f 0550dcd8 ffffffc0 00000000 00000000
fe60: 0514fe70 ffffffc0 000be1f8 ffffffc0 0514feb0 ffffffc0 0008948c ffffffc0
fe80: 00000004 00000000 0514fed0 ffffffc0 ffffffff ffffffff 9282a948 0000007f
fea0: 00000000 00000000 9282b708 0000007f c1592820 0000007f 00083914 ffffffc0
fec0: 00000000 00000000 00000010 00000000 00000064 00000000 00000001 00000000
fee0: 005101e0 00000000 c1594680 0000007f c1594740 0000007f ffffffd8 ffffff80
ff00: 00000000 00000000 00000000 00000000 c1594770 0000007f c1594770 0000007f
ff20: 00665e10 00000000 7f7f7f7f 7f7f7f7f 01010101 01010101 00000000 00000000
ff40: 928e4cc0 0000007f 91ff11e8 0000007f
call_break_hook is called in atomic context (hard irq disabled), so replace
the sleepable lock to rcu lock, replace relevant list operations to rcu
version and call synchronize_rcu() in unregister_break_hook().
And, replace write lock to spinlock in {un}register_break_hook.
Signed-off-by: Yang Shi <yang.shi@linaro.org>
---
v2 -> v3
Add synchronize_rcu() in ungister_break_hook()
Replace write lock to spinlock
v1 -> v2
Replace list operations to rcu version.
arch/arm64/kernel/debug-monitors.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index cebf786..13ca9cd 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -271,20 +271,21 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
* Use reader/writer locks instead of plain spinlock.
*/
static LIST_HEAD(break_hook);
-static DEFINE_RWLOCK(break_hook_lock);
+static DEFINE_SPINLOCK(break_hook_lock);
void register_break_hook(struct break_hook *hook)
{
- write_lock(&break_hook_lock);
- list_add(&hook->node, &break_hook);
- write_unlock(&break_hook_lock);
+ spin_lock(&break_hook_lock);
+ list_add_rcu(&hook->node, &break_hook);
+ spin_unlock(&break_hook_lock);
}
void unregister_break_hook(struct break_hook *hook)
{
- write_lock(&break_hook_lock);
- list_del(&hook->node);
- write_unlock(&break_hook_lock);
+ spin_lock(&break_hook_lock);
+ list_del_rcu(&hook->node);
+ spin_unlock(&break_hook_lock);
+ synchronize_rcu();
}
static int call_break_hook(struct pt_regs *regs, unsigned int esr)
@@ -292,11 +293,11 @@ static int call_break_hook(struct pt_regs *regs, unsigned int esr)
struct break_hook *hook;
int (*fn)(struct pt_regs *regs, unsigned int esr) = NULL;
- read_lock(&break_hook_lock);
- list_for_each_entry(hook, &break_hook, node)
+ rcu_read_lock();
+ list_for_each_entry_rcu(hook, &break_hook, node)
if ((esr & hook->esr_mask) == hook->esr_val)
fn = hook->fn;
- read_unlock(&break_hook_lock);
+ rcu_read_unlock();
return fn ? fn(regs, esr) : DBG_HOOK_ERROR;
}
--
2.0.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [v3 PATCH] arm64: replace read_lock to rcu lock in call_break_hook
@ 2015-10-05 21:32 ` Yang Shi
0 siblings, 0 replies; 8+ messages in thread
From: Yang Shi @ 2015-10-05 21:32 UTC (permalink / raw)
To: linux-arm-kernel
BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
in_atomic(): 0, irqs_disabled(): 128, pid: 342, name: perf
1 lock held by perf/342:
#0: (break_hook_lock){+.+...}, at: [<ffffffc0000851ac>] call_break_hook+0x34/0xd0
irq event stamp: 62224
hardirqs last enabled at (62223): [<ffffffc00010b7bc>] __call_rcu.constprop.59+0x104/0x270
hardirqs last disabled at (62224): [<ffffffc0000fbe20>] vprintk_emit+0x68/0x640
softirqs last enabled at (0): [<ffffffc000097928>] copy_process.part.8+0x428/0x17f8
softirqs last disabled at (0): [< (null)>] (null)
CPU: 0 PID: 342 Comm: perf Not tainted 4.1.6-rt5 #4
Hardware name: linux,dummy-virt (DT)
Call trace:
[<ffffffc000089968>] dump_backtrace+0x0/0x128
[<ffffffc000089ab0>] show_stack+0x20/0x30
[<ffffffc0007030d0>] dump_stack+0x7c/0xa0
[<ffffffc0000c878c>] ___might_sleep+0x174/0x260
[<ffffffc000708ac8>] __rt_spin_lock+0x28/0x40
[<ffffffc000708db0>] rt_read_lock+0x60/0x80
[<ffffffc0000851a8>] call_break_hook+0x30/0xd0
[<ffffffc000085a70>] brk_handler+0x30/0x98
[<ffffffc000082248>] do_debug_exception+0x50/0xb8
Exception stack(0xffffffc00514fe30 to 0xffffffc00514ff50)
fe20: 00000000 00000000 c1594680 0000007f
fe40: ffffffff ffffffff 92063940 0000007f 0550dcd8 ffffffc0 00000000 00000000
fe60: 0514fe70 ffffffc0 000be1f8 ffffffc0 0514feb0 ffffffc0 0008948c ffffffc0
fe80: 00000004 00000000 0514fed0 ffffffc0 ffffffff ffffffff 9282a948 0000007f
fea0: 00000000 00000000 9282b708 0000007f c1592820 0000007f 00083914 ffffffc0
fec0: 00000000 00000000 00000010 00000000 00000064 00000000 00000001 00000000
fee0: 005101e0 00000000 c1594680 0000007f c1594740 0000007f ffffffd8 ffffff80
ff00: 00000000 00000000 00000000 00000000 c1594770 0000007f c1594770 0000007f
ff20: 00665e10 00000000 7f7f7f7f 7f7f7f7f 01010101 01010101 00000000 00000000
ff40: 928e4cc0 0000007f 91ff11e8 0000007f
call_break_hook is called in atomic context (hard irq disabled), so replace
the sleepable lock to rcu lock, replace relevant list operations to rcu
version and call synchronize_rcu() in unregister_break_hook().
And, replace write lock to spinlock in {un}register_break_hook.
Signed-off-by: Yang Shi <yang.shi@linaro.org>
---
v2 -> v3
Add synchronize_rcu() in ungister_break_hook()
Replace write lock to spinlock
v1 -> v2
Replace list operations to rcu version.
arch/arm64/kernel/debug-monitors.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index cebf786..13ca9cd 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -271,20 +271,21 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
* Use reader/writer locks instead of plain spinlock.
*/
static LIST_HEAD(break_hook);
-static DEFINE_RWLOCK(break_hook_lock);
+static DEFINE_SPINLOCK(break_hook_lock);
void register_break_hook(struct break_hook *hook)
{
- write_lock(&break_hook_lock);
- list_add(&hook->node, &break_hook);
- write_unlock(&break_hook_lock);
+ spin_lock(&break_hook_lock);
+ list_add_rcu(&hook->node, &break_hook);
+ spin_unlock(&break_hook_lock);
}
void unregister_break_hook(struct break_hook *hook)
{
- write_lock(&break_hook_lock);
- list_del(&hook->node);
- write_unlock(&break_hook_lock);
+ spin_lock(&break_hook_lock);
+ list_del_rcu(&hook->node);
+ spin_unlock(&break_hook_lock);
+ synchronize_rcu();
}
static int call_break_hook(struct pt_regs *regs, unsigned int esr)
@@ -292,11 +293,11 @@ static int call_break_hook(struct pt_regs *regs, unsigned int esr)
struct break_hook *hook;
int (*fn)(struct pt_regs *regs, unsigned int esr) = NULL;
- read_lock(&break_hook_lock);
- list_for_each_entry(hook, &break_hook, node)
+ rcu_read_lock();
+ list_for_each_entry_rcu(hook, &break_hook, node)
if ((esr & hook->esr_mask) == hook->esr_val)
fn = hook->fn;
- read_unlock(&break_hook_lock);
+ rcu_read_unlock();
return fn ? fn(regs, esr) : DBG_HOOK_ERROR;
}
--
2.0.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [v3 PATCH] arm64: replace read_lock to rcu lock in call_break_hook
2015-10-05 21:32 ` Yang Shi
@ 2015-10-08 23:55 ` Paul E. McKenney
-1 siblings, 0 replies; 8+ messages in thread
From: Paul E. McKenney @ 2015-10-08 23:55 UTC (permalink / raw)
To: Yang Shi
Cc: rostedt, catalin.marinas, will.deacon, dave.long, panand,
linux-kernel, linux-rt-users, linux-arm-kernel, linaro-kernel
On Mon, Oct 05, 2015 at 02:32:51PM -0700, Yang Shi wrote:
> BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
> in_atomic(): 0, irqs_disabled(): 128, pid: 342, name: perf
> 1 lock held by perf/342:
> #0: (break_hook_lock){+.+...}, at: [<ffffffc0000851ac>] call_break_hook+0x34/0xd0
> irq event stamp: 62224
> hardirqs last enabled at (62223): [<ffffffc00010b7bc>] __call_rcu.constprop.59+0x104/0x270
> hardirqs last disabled at (62224): [<ffffffc0000fbe20>] vprintk_emit+0x68/0x640
> softirqs last enabled at (0): [<ffffffc000097928>] copy_process.part.8+0x428/0x17f8
> softirqs last disabled at (0): [< (null)>] (null)
> CPU: 0 PID: 342 Comm: perf Not tainted 4.1.6-rt5 #4
> Hardware name: linux,dummy-virt (DT)
> Call trace:
> [<ffffffc000089968>] dump_backtrace+0x0/0x128
> [<ffffffc000089ab0>] show_stack+0x20/0x30
> [<ffffffc0007030d0>] dump_stack+0x7c/0xa0
> [<ffffffc0000c878c>] ___might_sleep+0x174/0x260
> [<ffffffc000708ac8>] __rt_spin_lock+0x28/0x40
> [<ffffffc000708db0>] rt_read_lock+0x60/0x80
> [<ffffffc0000851a8>] call_break_hook+0x30/0xd0
> [<ffffffc000085a70>] brk_handler+0x30/0x98
> [<ffffffc000082248>] do_debug_exception+0x50/0xb8
> Exception stack(0xffffffc00514fe30 to 0xffffffc00514ff50)
> fe20: 00000000 00000000 c1594680 0000007f
> fe40: ffffffff ffffffff 92063940 0000007f 0550dcd8 ffffffc0 00000000 00000000
> fe60: 0514fe70 ffffffc0 000be1f8 ffffffc0 0514feb0 ffffffc0 0008948c ffffffc0
> fe80: 00000004 00000000 0514fed0 ffffffc0 ffffffff ffffffff 9282a948 0000007f
> fea0: 00000000 00000000 9282b708 0000007f c1592820 0000007f 00083914 ffffffc0
> fec0: 00000000 00000000 00000010 00000000 00000064 00000000 00000001 00000000
> fee0: 005101e0 00000000 c1594680 0000007f c1594740 0000007f ffffffd8 ffffff80
> ff00: 00000000 00000000 00000000 00000000 c1594770 0000007f c1594770 0000007f
> ff20: 00665e10 00000000 7f7f7f7f 7f7f7f7f 01010101 01010101 00000000 00000000
> ff40: 928e4cc0 0000007f 91ff11e8 0000007f
>
> call_break_hook is called in atomic context (hard irq disabled), so replace
> the sleepable lock to rcu lock, replace relevant list operations to rcu
> version and call synchronize_rcu() in unregister_break_hook().
>
> And, replace write lock to spinlock in {un}register_break_hook.
>
> Signed-off-by: Yang Shi <yang.shi@linaro.org>
Looks more plausible to me. Does it look OK to you, Steven?
Thanx, Paul
> ---
> v2 -> v3
> Add synchronize_rcu() in ungister_break_hook()
> Replace write lock to spinlock
>
> v1 -> v2
> Replace list operations to rcu version.
>
> arch/arm64/kernel/debug-monitors.c | 21 +++++++++++----------
> 1 file changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
> index cebf786..13ca9cd 100644
> --- a/arch/arm64/kernel/debug-monitors.c
> +++ b/arch/arm64/kernel/debug-monitors.c
> @@ -271,20 +271,21 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
> * Use reader/writer locks instead of plain spinlock.
> */
> static LIST_HEAD(break_hook);
> -static DEFINE_RWLOCK(break_hook_lock);
> +static DEFINE_SPINLOCK(break_hook_lock);
>
> void register_break_hook(struct break_hook *hook)
> {
> - write_lock(&break_hook_lock);
> - list_add(&hook->node, &break_hook);
> - write_unlock(&break_hook_lock);
> + spin_lock(&break_hook_lock);
> + list_add_rcu(&hook->node, &break_hook);
> + spin_unlock(&break_hook_lock);
> }
>
> void unregister_break_hook(struct break_hook *hook)
> {
> - write_lock(&break_hook_lock);
> - list_del(&hook->node);
> - write_unlock(&break_hook_lock);
> + spin_lock(&break_hook_lock);
> + list_del_rcu(&hook->node);
> + spin_unlock(&break_hook_lock);
> + synchronize_rcu();
> }
>
> static int call_break_hook(struct pt_regs *regs, unsigned int esr)
> @@ -292,11 +293,11 @@ static int call_break_hook(struct pt_regs *regs, unsigned int esr)
> struct break_hook *hook;
> int (*fn)(struct pt_regs *regs, unsigned int esr) = NULL;
>
> - read_lock(&break_hook_lock);
> - list_for_each_entry(hook, &break_hook, node)
> + rcu_read_lock();
> + list_for_each_entry_rcu(hook, &break_hook, node)
> if ((esr & hook->esr_mask) == hook->esr_val)
> fn = hook->fn;
> - read_unlock(&break_hook_lock);
> + rcu_read_unlock();
>
> return fn ? fn(regs, esr) : DBG_HOOK_ERROR;
> }
> --
> 2.0.2
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* [v3 PATCH] arm64: replace read_lock to rcu lock in call_break_hook
@ 2015-10-08 23:55 ` Paul E. McKenney
0 siblings, 0 replies; 8+ messages in thread
From: Paul E. McKenney @ 2015-10-08 23:55 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, Oct 05, 2015 at 02:32:51PM -0700, Yang Shi wrote:
> BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
> in_atomic(): 0, irqs_disabled(): 128, pid: 342, name: perf
> 1 lock held by perf/342:
> #0: (break_hook_lock){+.+...}, at: [<ffffffc0000851ac>] call_break_hook+0x34/0xd0
> irq event stamp: 62224
> hardirqs last enabled at (62223): [<ffffffc00010b7bc>] __call_rcu.constprop.59+0x104/0x270
> hardirqs last disabled at (62224): [<ffffffc0000fbe20>] vprintk_emit+0x68/0x640
> softirqs last enabled at (0): [<ffffffc000097928>] copy_process.part.8+0x428/0x17f8
> softirqs last disabled at (0): [< (null)>] (null)
> CPU: 0 PID: 342 Comm: perf Not tainted 4.1.6-rt5 #4
> Hardware name: linux,dummy-virt (DT)
> Call trace:
> [<ffffffc000089968>] dump_backtrace+0x0/0x128
> [<ffffffc000089ab0>] show_stack+0x20/0x30
> [<ffffffc0007030d0>] dump_stack+0x7c/0xa0
> [<ffffffc0000c878c>] ___might_sleep+0x174/0x260
> [<ffffffc000708ac8>] __rt_spin_lock+0x28/0x40
> [<ffffffc000708db0>] rt_read_lock+0x60/0x80
> [<ffffffc0000851a8>] call_break_hook+0x30/0xd0
> [<ffffffc000085a70>] brk_handler+0x30/0x98
> [<ffffffc000082248>] do_debug_exception+0x50/0xb8
> Exception stack(0xffffffc00514fe30 to 0xffffffc00514ff50)
> fe20: 00000000 00000000 c1594680 0000007f
> fe40: ffffffff ffffffff 92063940 0000007f 0550dcd8 ffffffc0 00000000 00000000
> fe60: 0514fe70 ffffffc0 000be1f8 ffffffc0 0514feb0 ffffffc0 0008948c ffffffc0
> fe80: 00000004 00000000 0514fed0 ffffffc0 ffffffff ffffffff 9282a948 0000007f
> fea0: 00000000 00000000 9282b708 0000007f c1592820 0000007f 00083914 ffffffc0
> fec0: 00000000 00000000 00000010 00000000 00000064 00000000 00000001 00000000
> fee0: 005101e0 00000000 c1594680 0000007f c1594740 0000007f ffffffd8 ffffff80
> ff00: 00000000 00000000 00000000 00000000 c1594770 0000007f c1594770 0000007f
> ff20: 00665e10 00000000 7f7f7f7f 7f7f7f7f 01010101 01010101 00000000 00000000
> ff40: 928e4cc0 0000007f 91ff11e8 0000007f
>
> call_break_hook is called in atomic context (hard irq disabled), so replace
> the sleepable lock to rcu lock, replace relevant list operations to rcu
> version and call synchronize_rcu() in unregister_break_hook().
>
> And, replace write lock to spinlock in {un}register_break_hook.
>
> Signed-off-by: Yang Shi <yang.shi@linaro.org>
Looks more plausible to me. Does it look OK to you, Steven?
Thanx, Paul
> ---
> v2 -> v3
> Add synchronize_rcu() in ungister_break_hook()
> Replace write lock to spinlock
>
> v1 -> v2
> Replace list operations to rcu version.
>
> arch/arm64/kernel/debug-monitors.c | 21 +++++++++++----------
> 1 file changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
> index cebf786..13ca9cd 100644
> --- a/arch/arm64/kernel/debug-monitors.c
> +++ b/arch/arm64/kernel/debug-monitors.c
> @@ -271,20 +271,21 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
> * Use reader/writer locks instead of plain spinlock.
> */
> static LIST_HEAD(break_hook);
> -static DEFINE_RWLOCK(break_hook_lock);
> +static DEFINE_SPINLOCK(break_hook_lock);
>
> void register_break_hook(struct break_hook *hook)
> {
> - write_lock(&break_hook_lock);
> - list_add(&hook->node, &break_hook);
> - write_unlock(&break_hook_lock);
> + spin_lock(&break_hook_lock);
> + list_add_rcu(&hook->node, &break_hook);
> + spin_unlock(&break_hook_lock);
> }
>
> void unregister_break_hook(struct break_hook *hook)
> {
> - write_lock(&break_hook_lock);
> - list_del(&hook->node);
> - write_unlock(&break_hook_lock);
> + spin_lock(&break_hook_lock);
> + list_del_rcu(&hook->node);
> + spin_unlock(&break_hook_lock);
> + synchronize_rcu();
> }
>
> static int call_break_hook(struct pt_regs *regs, unsigned int esr)
> @@ -292,11 +293,11 @@ static int call_break_hook(struct pt_regs *regs, unsigned int esr)
> struct break_hook *hook;
> int (*fn)(struct pt_regs *regs, unsigned int esr) = NULL;
>
> - read_lock(&break_hook_lock);
> - list_for_each_entry(hook, &break_hook, node)
> + rcu_read_lock();
> + list_for_each_entry_rcu(hook, &break_hook, node)
> if ((esr & hook->esr_mask) == hook->esr_val)
> fn = hook->fn;
> - read_unlock(&break_hook_lock);
> + rcu_read_unlock();
>
> return fn ? fn(regs, esr) : DBG_HOOK_ERROR;
> }
> --
> 2.0.2
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [v3 PATCH] arm64: replace read_lock to rcu lock in call_break_hook
2015-10-08 23:55 ` Paul E. McKenney
@ 2015-10-09 9:05 ` Will Deacon
-1 siblings, 0 replies; 8+ messages in thread
From: Will Deacon @ 2015-10-09 9:05 UTC (permalink / raw)
To: Paul E. McKenney
Cc: Yang Shi, rostedt, catalin.marinas, dave.long, panand,
linux-kernel, linux-rt-users, linux-arm-kernel, linaro-kernel
On Thu, Oct 08, 2015 at 04:55:38PM -0700, Paul E. McKenney wrote:
> On Mon, Oct 05, 2015 at 02:32:51PM -0700, Yang Shi wrote:
> > BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
> > in_atomic(): 0, irqs_disabled(): 128, pid: 342, name: perf
> > 1 lock held by perf/342:
> > #0: (break_hook_lock){+.+...}, at: [<ffffffc0000851ac>] call_break_hook+0x34/0xd0
> > irq event stamp: 62224
> > hardirqs last enabled at (62223): [<ffffffc00010b7bc>] __call_rcu.constprop.59+0x104/0x270
> > hardirqs last disabled at (62224): [<ffffffc0000fbe20>] vprintk_emit+0x68/0x640
> > softirqs last enabled at (0): [<ffffffc000097928>] copy_process.part.8+0x428/0x17f8
> > softirqs last disabled at (0): [< (null)>] (null)
> > CPU: 0 PID: 342 Comm: perf Not tainted 4.1.6-rt5 #4
> > Hardware name: linux,dummy-virt (DT)
> > Call trace:
> > [<ffffffc000089968>] dump_backtrace+0x0/0x128
> > [<ffffffc000089ab0>] show_stack+0x20/0x30
> > [<ffffffc0007030d0>] dump_stack+0x7c/0xa0
> > [<ffffffc0000c878c>] ___might_sleep+0x174/0x260
> > [<ffffffc000708ac8>] __rt_spin_lock+0x28/0x40
> > [<ffffffc000708db0>] rt_read_lock+0x60/0x80
> > [<ffffffc0000851a8>] call_break_hook+0x30/0xd0
> > [<ffffffc000085a70>] brk_handler+0x30/0x98
> > [<ffffffc000082248>] do_debug_exception+0x50/0xb8
> > Exception stack(0xffffffc00514fe30 to 0xffffffc00514ff50)
> > fe20: 00000000 00000000 c1594680 0000007f
> > fe40: ffffffff ffffffff 92063940 0000007f 0550dcd8 ffffffc0 00000000 00000000
> > fe60: 0514fe70 ffffffc0 000be1f8 ffffffc0 0514feb0 ffffffc0 0008948c ffffffc0
> > fe80: 00000004 00000000 0514fed0 ffffffc0 ffffffff ffffffff 9282a948 0000007f
> > fea0: 00000000 00000000 9282b708 0000007f c1592820 0000007f 00083914 ffffffc0
> > fec0: 00000000 00000000 00000010 00000000 00000064 00000000 00000001 00000000
> > fee0: 005101e0 00000000 c1594680 0000007f c1594740 0000007f ffffffd8 ffffff80
> > ff00: 00000000 00000000 00000000 00000000 c1594770 0000007f c1594770 0000007f
> > ff20: 00665e10 00000000 7f7f7f7f 7f7f7f7f 01010101 01010101 00000000 00000000
> > ff40: 928e4cc0 0000007f 91ff11e8 0000007f
> >
> > call_break_hook is called in atomic context (hard irq disabled), so replace
> > the sleepable lock to rcu lock, replace relevant list operations to rcu
> > version and call synchronize_rcu() in unregister_break_hook().
> >
> > And, replace write lock to spinlock in {un}register_break_hook.
> >
> > Signed-off-by: Yang Shi <yang.shi@linaro.org>
>
> Looks more plausible to me. Does it look OK to you, Steven?
This is already in mainline as a fix, so please shout loudly if you think
it's broken (it looked ok to me and didn't cause any regressions in my
testing).
Will
^ permalink raw reply [flat|nested] 8+ messages in thread
* [v3 PATCH] arm64: replace read_lock to rcu lock in call_break_hook
@ 2015-10-09 9:05 ` Will Deacon
0 siblings, 0 replies; 8+ messages in thread
From: Will Deacon @ 2015-10-09 9:05 UTC (permalink / raw)
To: linux-arm-kernel
On Thu, Oct 08, 2015 at 04:55:38PM -0700, Paul E. McKenney wrote:
> On Mon, Oct 05, 2015 at 02:32:51PM -0700, Yang Shi wrote:
> > BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
> > in_atomic(): 0, irqs_disabled(): 128, pid: 342, name: perf
> > 1 lock held by perf/342:
> > #0: (break_hook_lock){+.+...}, at: [<ffffffc0000851ac>] call_break_hook+0x34/0xd0
> > irq event stamp: 62224
> > hardirqs last enabled at (62223): [<ffffffc00010b7bc>] __call_rcu.constprop.59+0x104/0x270
> > hardirqs last disabled at (62224): [<ffffffc0000fbe20>] vprintk_emit+0x68/0x640
> > softirqs last enabled at (0): [<ffffffc000097928>] copy_process.part.8+0x428/0x17f8
> > softirqs last disabled at (0): [< (null)>] (null)
> > CPU: 0 PID: 342 Comm: perf Not tainted 4.1.6-rt5 #4
> > Hardware name: linux,dummy-virt (DT)
> > Call trace:
> > [<ffffffc000089968>] dump_backtrace+0x0/0x128
> > [<ffffffc000089ab0>] show_stack+0x20/0x30
> > [<ffffffc0007030d0>] dump_stack+0x7c/0xa0
> > [<ffffffc0000c878c>] ___might_sleep+0x174/0x260
> > [<ffffffc000708ac8>] __rt_spin_lock+0x28/0x40
> > [<ffffffc000708db0>] rt_read_lock+0x60/0x80
> > [<ffffffc0000851a8>] call_break_hook+0x30/0xd0
> > [<ffffffc000085a70>] brk_handler+0x30/0x98
> > [<ffffffc000082248>] do_debug_exception+0x50/0xb8
> > Exception stack(0xffffffc00514fe30 to 0xffffffc00514ff50)
> > fe20: 00000000 00000000 c1594680 0000007f
> > fe40: ffffffff ffffffff 92063940 0000007f 0550dcd8 ffffffc0 00000000 00000000
> > fe60: 0514fe70 ffffffc0 000be1f8 ffffffc0 0514feb0 ffffffc0 0008948c ffffffc0
> > fe80: 00000004 00000000 0514fed0 ffffffc0 ffffffff ffffffff 9282a948 0000007f
> > fea0: 00000000 00000000 9282b708 0000007f c1592820 0000007f 00083914 ffffffc0
> > fec0: 00000000 00000000 00000010 00000000 00000064 00000000 00000001 00000000
> > fee0: 005101e0 00000000 c1594680 0000007f c1594740 0000007f ffffffd8 ffffff80
> > ff00: 00000000 00000000 00000000 00000000 c1594770 0000007f c1594770 0000007f
> > ff20: 00665e10 00000000 7f7f7f7f 7f7f7f7f 01010101 01010101 00000000 00000000
> > ff40: 928e4cc0 0000007f 91ff11e8 0000007f
> >
> > call_break_hook is called in atomic context (hard irq disabled), so replace
> > the sleepable lock to rcu lock, replace relevant list operations to rcu
> > version and call synchronize_rcu() in unregister_break_hook().
> >
> > And, replace write lock to spinlock in {un}register_break_hook.
> >
> > Signed-off-by: Yang Shi <yang.shi@linaro.org>
>
> Looks more plausible to me. Does it look OK to you, Steven?
This is already in mainline as a fix, so please shout loudly if you think
it's broken (it looked ok to me and didn't cause any regressions in my
testing).
Will
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [v3 PATCH] arm64: replace read_lock to rcu lock in call_break_hook
2015-10-09 9:05 ` Will Deacon
@ 2015-10-09 17:02 ` Steven Rostedt
-1 siblings, 0 replies; 8+ messages in thread
From: Steven Rostedt @ 2015-10-09 17:02 UTC (permalink / raw)
To: Will Deacon
Cc: Paul E. McKenney, Yang Shi, catalin.marinas, dave.long, panand,
linux-kernel, linux-rt-users, linux-arm-kernel, linaro-kernel
On Fri, 9 Oct 2015 10:05:50 +0100
Will Deacon <will.deacon@arm.com> wrote:
> > Looks more plausible to me. Does it look OK to you, Steven?
>
> This is already in mainline as a fix, so please shout loudly if you think
> it's broken (it looked ok to me and didn't cause any regressions in my
> testing).
Looks good to me.
-- Steve
^ permalink raw reply [flat|nested] 8+ messages in thread
* [v3 PATCH] arm64: replace read_lock to rcu lock in call_break_hook
@ 2015-10-09 17:02 ` Steven Rostedt
0 siblings, 0 replies; 8+ messages in thread
From: Steven Rostedt @ 2015-10-09 17:02 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, 9 Oct 2015 10:05:50 +0100
Will Deacon <will.deacon@arm.com> wrote:
> > Looks more plausible to me. Does it look OK to you, Steven?
>
> This is already in mainline as a fix, so please shout loudly if you think
> it's broken (it looked ok to me and didn't cause any regressions in my
> testing).
Looks good to me.
-- Steve
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2015-10-09 17:02 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-10-05 21:32 [v3 PATCH] arm64: replace read_lock to rcu lock in call_break_hook Yang Shi
2015-10-05 21:32 ` Yang Shi
2015-10-08 23:55 ` Paul E. McKenney
2015-10-08 23:55 ` Paul E. McKenney
2015-10-09 9:05 ` Will Deacon
2015-10-09 9:05 ` Will Deacon
2015-10-09 17:02 ` Steven Rostedt
2015-10-09 17:02 ` Steven Rostedt
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