+++ /dev/null
-From 24904eeb4c8c9b2f4b03b5335af926e208a3120e Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Fri, 15 Dec 2023 22:34:24 +0100
-Subject: pinctrl: at91-pio4: use dedicated lock class for IRQ
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-
-From: Alexis Lothoré <alexis.lothore@bootlin.com>
-
-[ Upstream commit 14694179e561b5f2f7e56a0f590e2cb49a9cc7ab ]
-
-Trying to suspend to RAM on SAMA5D27 EVK leads to the following lockdep
-warning:
-
- ============================================
- WARNING: possible recursive locking detected
- 6.7.0-rc5-wt+ #532 Not tainted
- --------------------------------------------
- sh/92 is trying to acquire lock:
- c3cf306c (&irq_desc_lock_class){-.-.}-{2:2}, at: __irq_get_desc_lock+0xe8/0x100
-
- but task is already holding lock:
- c3d7c46c (&irq_desc_lock_class){-.-.}-{2:2}, at: __irq_get_desc_lock+0xe8/0x100
-
- other info that might help us debug this:
- Possible unsafe locking scenario:
-
- CPU0
- ----
- lock(&irq_desc_lock_class);
- lock(&irq_desc_lock_class);
-
- *** DEADLOCK ***
-
- May be due to missing lock nesting notation
-
- 6 locks held by sh/92:
- #0: c3aa0258 (sb_writers#6){.+.+}-{0:0}, at: ksys_write+0xd8/0x178
- #1: c4c2df44 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x138/0x284
- #2: c32684a0 (kn->active){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x148/0x284
- #3: c232b6d4 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend+0x13c/0x4e8
- #4: c387b088 (&dev->mutex){....}-{3:3}, at: __device_suspend+0x1e8/0x91c
- #5: c3d7c46c (&irq_desc_lock_class){-.-.}-{2:2}, at: __irq_get_desc_lock+0xe8/0x100
-
- stack backtrace:
- CPU: 0 PID: 92 Comm: sh Not tainted 6.7.0-rc5-wt+ #532
- Hardware name: Atmel SAMA5
- unwind_backtrace from show_stack+0x18/0x1c
- show_stack from dump_stack_lvl+0x34/0x48
- dump_stack_lvl from __lock_acquire+0x19ec/0x3a0c
- __lock_acquire from lock_acquire.part.0+0x124/0x2d0
- lock_acquire.part.0 from _raw_spin_lock_irqsave+0x5c/0x78
- _raw_spin_lock_irqsave from __irq_get_desc_lock+0xe8/0x100
- __irq_get_desc_lock from irq_set_irq_wake+0xa8/0x204
- irq_set_irq_wake from atmel_gpio_irq_set_wake+0x58/0xb4
- atmel_gpio_irq_set_wake from irq_set_irq_wake+0x100/0x204
- irq_set_irq_wake from gpio_keys_suspend+0xec/0x2b8
- gpio_keys_suspend from dpm_run_callback+0xe4/0x248
- dpm_run_callback from __device_suspend+0x234/0x91c
- __device_suspend from dpm_suspend+0x224/0x43c
- dpm_suspend from dpm_suspend_start+0x9c/0xa8
- dpm_suspend_start from suspend_devices_and_enter+0x1e0/0xa84
- suspend_devices_and_enter from pm_suspend+0x460/0x4e8
- pm_suspend from state_store+0x78/0xe4
- state_store from kernfs_fop_write_iter+0x1a0/0x284
- kernfs_fop_write_iter from vfs_write+0x38c/0x6f4
- vfs_write from ksys_write+0xd8/0x178
- ksys_write from ret_fast_syscall+0x0/0x1c
- Exception stack(0xc52b3fa8 to 0xc52b3ff0)
- 3fa0: 00000004 005a0ae8 00000001 005a0ae8 00000004 00000001
- 3fc0: 00000004 005a0ae8 00000001 00000004 00000004 b6c616c0 00000020 0059d190
- 3fe0: 00000004 b6c61678 aec5a041 aebf1a26
-
-This warning is raised because pinctrl-at91-pio4 uses chained IRQ. Whenever
-a wake up source configures an IRQ through irq_set_irq_wake, it will
-lock the corresponding IRQ desc, and then call irq_set_irq_wake on "parent"
-IRQ which will do the same on its own IRQ desc, but since those two locks
-share the same class, lockdep reports this as an issue.
-
-Fix lockdep false positive by setting a different class for parent and
-children IRQ
-
-Fixes: 776180848b57 ("pinctrl: introduce driver for Atmel PIO4 controller")
-Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
-Link: https://lore.kernel.org/r/20231215-lockdep_warning-v1-1-8137b2510ed5@bootlin.com
-Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- drivers/pinctrl/pinctrl-at91-pio4.c | 8 ++++++++
- 1 file changed, 8 insertions(+)
-
-diff --git a/drivers/pinctrl/pinctrl-at91-pio4.c b/drivers/pinctrl/pinctrl-at91-pio4.c
-index 8f18a35b66b61..5ef7dd8c9ccf0 100644
---- a/drivers/pinctrl/pinctrl-at91-pio4.c
-+++ b/drivers/pinctrl/pinctrl-at91-pio4.c
-@@ -899,6 +899,13 @@ static const struct of_device_id atmel_pctrl_of_match[] = {
- }
- };
-
-+/*
-+ * This lock class allows to tell lockdep that parent IRQ and children IRQ do
-+ * not share the same class so it does not raise false positive
-+ */
-+static struct lock_class_key atmel_lock_key;
-+static struct lock_class_key atmel_request_key;
-+
- static int atmel_pinctrl_probe(struct platform_device *pdev)
- {
- struct device *dev = &pdev->dev;
-@@ -1044,6 +1051,7 @@ static int atmel_pinctrl_probe(struct platform_device *pdev)
- irq_set_chip_and_handler(irq, &atmel_gpio_irq_chip,
- handle_simple_irq);
- irq_set_chip_data(irq, atmel_pioctrl);
-+ irq_set_lockdep_class(irq, &atmel_lock_key, &atmel_request_key);
- dev_dbg(dev,
- "atmel gpio irq domain: hwirq: %d, linux irq: %d\n",
- i, irq);
---
-2.43.0
-
projects / thirdparty / kernel / stable-queue.git / commitdiff
