linux-kernel - [tip: timers/clocksource] clocksource/drivers/exynos

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Message-ID: <175343950142.1420.14962601224328068105.tip-bot2@tip-bot2>
Date: Fri, 25 Jul 2025 10:31:41 -0000
From: "tip-bot2 for Will McVicker" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Will McVicker <willmcvicker@...gle.com>,
 Daniel Lezcano <daniel.lezcano@...aro.org>, Ingo Molnar <mingo@...nel.org>,
 Youngmin Nam <youngmin.nam@...sung.com>,
 Peter Griffin <peter.griffin@...aro.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: timers/clocksource] clocksource/drivers/exynos_mct: Fix
 uninitialized IRQ name warning

The following commit has been merged into the timers/clocksource branch of tip:

Commit-ID:     32abb4c011457219ee7cd5188efba65ea7030187
Gitweb:        https://git.kernel.org/tip/32abb4c011457219ee7cd5188efba65ea7030187
Author:        Will McVicker <willmcvicker@...gle.com>
AuthorDate:    Fri, 20 Jun 2025 11:17:07 -07:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Fri, 25 Jul 2025 12:06:04 +02:00

clocksource/drivers/exynos_mct: Fix uninitialized IRQ name warning

The Exynos MCT driver doesn't set the clocksource name until the CPU
hotplug state is setup which happens after the IRQs are requested. This
results in an empty IRQ name which leads to the below warning at
proc_create() time. When this happens, the userdata partition fails to
mount and the device gets stuck in an endless loop printing the error:

  root '/dev/disk/by-partlabel/userdata' doesn't exist or does not contain a /dev.

To fix this, we just need to initialize the name before requesting the
IRQs.

Warning from Pixel 6 kernel log:

[  T430] name len 0
[  T430] WARNING: CPU: 6 PID: 430 at fs/proc/generic.c:407 __proc_create+0x258/0x2b4
[  T430] Modules linked in: dwc3_exynos(E+)
[  T430]  ufs_exynos(E+) phy_exynos_ufs(E)
[  T430]  phy_exynos5_usbdrd(E) exynos_usi(E+) exynos_mct(E+) s3c2410_wdt(E)
[  T430]  arm_dsu_pmu(E) simplefb(E)
[  T430] CPU: 6 UID: 0 PID: 430 Comm: (udev-worker) Tainted:
         ... 6.14.0-next-20250331-4k-00008-g59adf909e40e #1 ...
[  T430] Tainted: [W]=WARN, [E]=UNSIGNED_MODULE
[  T430] Hardware name: Raven (DT)
[...]
[  T430] Call trace:
[  T430]  __proc_create+0x258/0x2b4 (P)
[  T430]  proc_mkdir+0x40/0xa0
[  T430]  register_handler_proc+0x118/0x140
[  T430]  __setup_irq+0x460/0x6d0
[  T430]  request_threaded_irq+0xcc/0x1b0
[  T430]  mct_init_dt+0x244/0x604 [exynos_mct ...]
[  T430]  mct_init_spi+0x18/0x34 [exynos_mct ...]
[  T430]  exynos4_mct_probe+0x30/0x4c [exynos_mct ...]
[  T430]  platform_probe+0x6c/0xe4
[  T430]  really_probe+0xf4/0x38c
[...]
[  T430]  driver_register+0x6c/0x140
[  T430]  __platform_driver_register+0x28/0x38
[  T430]  exynos4_mct_driver_init+0x24/0xfe8 [exynos_mct ...]
[  T430]  do_one_initcall+0x84/0x3c0
[  T430]  do_init_module+0x58/0x208
[  T430]  load_module+0x1de0/0x2500
[  T430]  init_module_from_file+0x8c/0xdc

Signed-off-by: Will McVicker <willmcvicker@...gle.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Tested-by: Youngmin Nam <youngmin.nam@...sung.com>
Reviewed-by: Peter Griffin <peter.griffin@...aro.org>
Reviewed-by: Youngmin Nam <youngmin.nam@...sung.com>
Link: https://lore.kernel.org/r/20250620181719.1399856-5-willmcvicker@google.com
---
 drivers/clocksource/exynos_mct.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index a5ef7d6..62febeb 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -465,8 +465,6 @@ static int exynos4_mct_starting_cpu(unsigned int cpu)
 		per_cpu_ptr(&percpu_mct_tick, cpu);
 	struct clock_event_device *evt = &mevt->evt;
 
-	snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu);
-
 	evt->name = mevt->name;
 	evt->cpumask = cpumask_of(cpu);
 	evt->set_next_event = exynos4_tick_set_next_event;
@@ -567,6 +565,14 @@ static int __init exynos4_timer_interrupts(struct device_node *np,
 	for (i = MCT_L0_IRQ; i < nr_irqs; i++)
 		mct_irqs[i] = irq_of_parse_and_map(np, i);
 
+	for_each_possible_cpu(cpu) {
+		struct mct_clock_event_device *mevt =
+		    per_cpu_ptr(&percpu_mct_tick, cpu);
+
+		snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d",
+			 cpu);
+	}
+
 	if (mct_int_type == MCT_INT_PPI) {
 
 		err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],