| From acba3ca0949e9d5841542363b96bca728efafe9e Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 4 Jun 2020 13:23:17 +0200 |
| Subject: um: change sigio_spinlock to a mutex |
| |
| From: Johannes Berg <johannes.berg@intel.com> |
| |
| [ Upstream commit f2d05059e15af3f70502074f4e3a504530af504a ] |
| |
| Lockdep complains at boot: |
| |
| ============================= |
| [ BUG: Invalid wait context ] |
| 5.7.0-05093-g46d91ecd597b #98 Not tainted |
| ----------------------------- |
| swapper/1 is trying to lock: |
| 0000000060931b98 (&desc[i].request_mutex){+.+.}-{3:3}, at: __setup_irq+0x11d/0x623 |
| other info that might help us debug this: |
| context-{4:4} |
| 1 lock held by swapper/1: |
| #0: 000000006074fed8 (sigio_spinlock){+.+.}-{2:2}, at: sigio_lock+0x1a/0x1c |
| stack backtrace: |
| CPU: 0 PID: 1 Comm: swapper Not tainted 5.7.0-05093-g46d91ecd597b #98 |
| Stack: |
| 7fa4fab0 6028dfd1 0000002a 6008bea5 |
| 7fa50700 7fa50040 7fa4fac0 6028e016 |
| 7fa4fb50 6007f6da 60959c18 00000000 |
| Call Trace: |
| [<60023a0e>] show_stack+0x13b/0x155 |
| [<6028e016>] dump_stack+0x2a/0x2c |
| [<6007f6da>] __lock_acquire+0x515/0x15f2 |
| [<6007eb50>] lock_acquire+0x245/0x273 |
| [<6050d9f1>] __mutex_lock+0xbd/0x325 |
| [<6050dc76>] mutex_lock_nested+0x1d/0x1f |
| [<6008e27e>] __setup_irq+0x11d/0x623 |
| [<6008e8ed>] request_threaded_irq+0x169/0x1a6 |
| [<60021eb0>] um_request_irq+0x1ee/0x24b |
| [<600234ee>] write_sigio_irq+0x3b/0x76 |
| [<600383ca>] sigio_broken+0x146/0x2e4 |
| [<60020bd8>] do_one_initcall+0xde/0x281 |
| |
| Because we hold sigio_spinlock and then get into requesting |
| an interrupt with a mutex. |
| |
| Change the spinlock to a mutex to avoid that. |
| |
| Signed-off-by: Johannes Berg <johannes.berg@intel.com> |
| Signed-off-by: Richard Weinberger <richard@nod.at> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| arch/um/kernel/sigio.c | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| diff --git a/arch/um/kernel/sigio.c b/arch/um/kernel/sigio.c |
| index 10c99e058fcae..d1cffc2a7f212 100644 |
| --- a/arch/um/kernel/sigio.c |
| +++ b/arch/um/kernel/sigio.c |
| @@ -35,14 +35,14 @@ int write_sigio_irq(int fd) |
| } |
| |
| /* These are called from os-Linux/sigio.c to protect its pollfds arrays. */ |
| -static DEFINE_SPINLOCK(sigio_spinlock); |
| +static DEFINE_MUTEX(sigio_mutex); |
| |
| void sigio_lock(void) |
| { |
| - spin_lock(&sigio_spinlock); |
| + mutex_lock(&sigio_mutex); |
| } |
| |
| void sigio_unlock(void) |
| { |
| - spin_unlock(&sigio_spinlock); |
| + mutex_unlock(&sigio_mutex); |
| } |
| -- |
| 2.27.0 |
| |