| Message ID | 1454971764-30720-1-git-send-email-yang.shi@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
* Yang Shi | 2016-02-08 14:49:24 [-0800]: >BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 … >This issue is similar with 62c6c61("arm64: replace read_lock to rcu lock in >call_break_hook"), but comes to single_step_handler. > >This also solves kgdbts boot test silent hang issue on 4.4 -rt kernel. I am going to apply this for -RT. Sebastian
On Mon, Feb 08, 2016 at 02:49:24PM -0800, Yang Shi wrote: > BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 > in_atomic(): 1, irqs_disabled(): 128, pid: 383, name: sh > Preemption disabled at:[<ffff800000124c18>] kgdb_cpu_enter+0x158/0x6b8 > > CPU: 3 PID: 383 Comm: sh Tainted: G W 4.1.13-rt13 #2 > Hardware name: Freescale Layerscape 2085a RDB Board (DT) > Call trace: > [<ffff8000000885e8>] dump_backtrace+0x0/0x128 > [<ffff800000088734>] show_stack+0x24/0x30 > [<ffff80000079a7c4>] dump_stack+0x80/0xa0 > [<ffff8000000bd324>] ___might_sleep+0x18c/0x1a0 > [<ffff8000007a20ac>] __rt_spin_lock+0x2c/0x40 > [<ffff8000007a2268>] rt_read_lock+0x40/0x58 > [<ffff800000085328>] single_step_handler+0x38/0xd8 > [<ffff800000082368>] do_debug_exception+0x58/0xb8 > Exception stack(0xffff80834a1e7c80 to 0xffff80834a1e7da0) > 7c80: ffffff9c ffffffff 92c23ba0 0000ffff 4a1e7e40 ffff8083 001bfcc4 ffff8000 > 7ca0: f2000400 00000000 00000000 00000000 4a1e7d80 ffff8083 0049501c ffff8000 > 7cc0: 00005402 00000000 00aaa210 ffff8000 4a1e7ea0 ffff8083 000833f4 ffff8000 > 7ce0: ffffff9c ffffffff 92c23ba0 0000ffff 4a1e7ea0 ffff8083 001bfcc0 ffff8000 > 7d00: 4a0fc400 ffff8083 00005402 00000000 4a1e7d40 ffff8083 00490324 ffff8000 > 7d20: ffffff9c 00000000 92c23ba0 0000ffff 000a0000 00000000 00000000 00000000 > 7d40: 00000008 00000000 00080000 00000000 92c23b8b 0000ffff 92c23b8e 0000ffff > 7d60: 00000038 00000000 00001cb2 00000000 00000005 00000000 92d7b498 0000ffff > 7d80: 01010101 01010101 92be9000 0000ffff 00000000 00000000 00000030 00000000 > [<ffff8000000833f4>] el1_dbg+0x18/0x6c > > This issue is similar with 62c6c61("arm64: replace read_lock to rcu lock in > call_break_hook"), but comes to single_step_handler. > > This also solves kgdbts boot test silent hang issue on 4.4 -rt kernel. > > Signed-off-by: Yang Shi <yang.shi@linaro.org> Acked-by: Will Deacon <will.deacon@arm.com> Will
On Tue, 9 Feb 2016 14:54:26 +0000
Will Deacon <will.deacon@arm.com> wrote:
> Acked-by: Will Deacon <will.deacon@arm.com>
Will,
The patch looks good to me. Do you want to take it through your tree?
It benefits mainline too as a rcu_read_lock() is more efficient than
rwlocks. Although I will say this is a slow path anyway.
-- Steve
On Tue, Feb 09, 2016 at 10:07:58AM -0500, Steven Rostedt wrote: > On Tue, 9 Feb 2016 14:54:26 +0000 > Will Deacon <will.deacon@arm.com> wrote: > > > > Acked-by: Will Deacon <will.deacon@arm.com> > > Will, Hi Steve, > The patch looks good to me. Do you want to take it through your tree? > > It benefits mainline too as a rcu_read_lock() is more efficient than > rwlocks. Although I will say this is a slow path anyway. I was thinking that Catalin would queue it for 4.6 in the arm64 tree, since that's probably easiest in case any unlikely conflicts crop up. Will
On Tue, 9 Feb 2016 16:04:42 +0000 Will Deacon <will.deacon@arm.com> wrote: > > The patch looks good to me. Do you want to take it through your tree? > > > > It benefits mainline too as a rcu_read_lock() is more efficient than > > rwlocks. Although I will say this is a slow path anyway. > > I was thinking that Catalin would queue it for 4.6 in the arm64 tree, > since that's probably easiest in case any unlikely conflicts crop up. Oh, OK. That's fine. I just didn't want you to think that the RT folks were going to pull it in for mainline. -- Steve
On Tue, Feb 09, 2016 at 04:04:42PM +0000, Will Deacon wrote: > On Tue, Feb 09, 2016 at 10:07:58AM -0500, Steven Rostedt wrote: > > On Tue, 9 Feb 2016 14:54:26 +0000 > > Will Deacon <will.deacon@arm.com> wrote: > > > > > > > Acked-by: Will Deacon <will.deacon@arm.com> > > > The patch looks good to me. Do you want to take it through your tree? > > > > It benefits mainline too as a rcu_read_lock() is more efficient than > > rwlocks. Although I will say this is a slow path anyway. > > I was thinking that Catalin would queue it for 4.6 in the arm64 tree, > since that's probably easiest in case any unlikely conflicts crop up. Queued.
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index 8aee3ae..c1492ba 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -186,20 +186,21 @@ static void clear_regs_spsr_ss(struct pt_regs *regs) /* EL1 Single Step Handler hooks */ static LIST_HEAD(step_hook); -static DEFINE_RWLOCK(step_hook_lock); +static DEFINE_SPINLOCK(step_hook_lock); void register_step_hook(struct step_hook *hook) { - write_lock(&step_hook_lock); - list_add(&hook->node, &step_hook); - write_unlock(&step_hook_lock); + spin_lock(&step_hook_lock); + list_add_rcu(&hook->node, &step_hook); + spin_unlock(&step_hook_lock); } void unregister_step_hook(struct step_hook *hook) { - write_lock(&step_hook_lock); - list_del(&hook->node); - write_unlock(&step_hook_lock); + spin_lock(&step_hook_lock); + list_del_rcu(&hook->node); + spin_unlock(&step_hook_lock); + synchronize_rcu(); } /* @@ -213,15 +214,15 @@ static int call_step_hook(struct pt_regs *regs, unsigned int esr) struct step_hook *hook; int retval = DBG_HOOK_ERROR; - read_lock(&step_hook_lock); + rcu_read_lock(); - list_for_each_entry(hook, &step_hook, node) { + list_for_each_entry_rcu(hook, &step_hook, node) { retval = hook->fn(regs, esr); if (retval == DBG_HOOK_HANDLED) break; } - read_unlock(&step_hook_lock); + rcu_read_unlock(); return retval; }
BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 in_atomic(): 1, irqs_disabled(): 128, pid: 383, name: sh Preemption disabled at:[<ffff800000124c18>] kgdb_cpu_enter+0x158/0x6b8 CPU: 3 PID: 383 Comm: sh Tainted: G W 4.1.13-rt13 #2 Hardware name: Freescale Layerscape 2085a RDB Board (DT) Call trace: [<ffff8000000885e8>] dump_backtrace+0x0/0x128 [<ffff800000088734>] show_stack+0x24/0x30 [<ffff80000079a7c4>] dump_stack+0x80/0xa0 [<ffff8000000bd324>] ___might_sleep+0x18c/0x1a0 [<ffff8000007a20ac>] __rt_spin_lock+0x2c/0x40 [<ffff8000007a2268>] rt_read_lock+0x40/0x58 [<ffff800000085328>] single_step_handler+0x38/0xd8 [<ffff800000082368>] do_debug_exception+0x58/0xb8 Exception stack(0xffff80834a1e7c80 to 0xffff80834a1e7da0) 7c80: ffffff9c ffffffff 92c23ba0 0000ffff 4a1e7e40 ffff8083 001bfcc4 ffff8000 7ca0: f2000400 00000000 00000000 00000000 4a1e7d80 ffff8083 0049501c ffff8000 7cc0: 00005402 00000000 00aaa210 ffff8000 4a1e7ea0 ffff8083 000833f4 ffff8000 7ce0: ffffff9c ffffffff 92c23ba0 0000ffff 4a1e7ea0 ffff8083 001bfcc0 ffff8000 7d00: 4a0fc400 ffff8083 00005402 00000000 4a1e7d40 ffff8083 00490324 ffff8000 7d20: ffffff9c 00000000 92c23ba0 0000ffff 000a0000 00000000 00000000 00000000 7d40: 00000008 00000000 00080000 00000000 92c23b8b 0000ffff 92c23b8e 0000ffff 7d60: 00000038 00000000 00001cb2 00000000 00000005 00000000 92d7b498 0000ffff 7d80: 01010101 01010101 92be9000 0000ffff 00000000 00000000 00000030 00000000 [<ffff8000000833f4>] el1_dbg+0x18/0x6c This issue is similar with 62c6c61("arm64: replace read_lock to rcu lock in call_break_hook"), but comes to single_step_handler. This also solves kgdbts boot test silent hang issue on 4.4 -rt kernel. Signed-off-by: Yang Shi <yang.shi@linaro.org> --- arch/arm64/kernel/debug-monitors.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-)