linux-kernel - [PATCH RFC] soc: qcom: pmic_glink: Fix device access from worker during suspend

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250110-soc-qcom-pmic-glink-fix-device-access-on-worker-while-suspended-v1-1-e32fd6bf322e@linaro.org>
Date: Fri, 10 Jan 2025 17:29:51 +0200
From: Abel Vesa <abel.vesa@...aro.org>
To: Bjorn Andersson <andersson@...nel.org>, 
 Konrad Dybcio <konradybcio@...nel.org>
Cc: Caleb Connolly <caleb.connolly@...aro.org>, 
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, 
 Johan Hovold <johan@...nel.org>, Neil Armstrong <neil.armstrong@...aro.org>, 
 linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org, 
 stable@...r.kernel.org, Abel Vesa <abel.vesa@...aro.org>
Subject: [PATCH RFC] soc: qcom: pmic_glink: Fix device access from worker
 during suspend

The pmic_glink_altmode_worker() currently gets scheduled on the system_wq.
When the system is suspended (s2idle), the fact that the worker can be
scheduled to run while devices are still suspended provesto be a problem
when a Type-C retimer, switch or mux that is controlled over a bus like
I2C, because the I2C controller is suspended.

This has been proven to be the case on the X Elite boards where such
retimers (ParadeTech PS8830) are used in order to handle Type-C
orientation and altmode configuration. The following warning is thrown:

[   35.134876] i2c i2c-4: Transfer while suspended
[   35.143865] WARNING: CPU: 0 PID: 99 at drivers/i2c/i2c-core.h:56 __i2c_transfer+0xb4/0x57c [i2c_core]
[   35.352879] Workqueue: events pmic_glink_altmode_worker [pmic_glink_altmode]
[   35.360179] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[   35.455242] Call trace:
[   35.457826]  __i2c_transfer+0xb4/0x57c [i2c_core] (P)
[   35.463086]  i2c_transfer+0x98/0xf0 [i2c_core]
[   35.467713]  i2c_transfer_buffer_flags+0x54/0x88 [i2c_core]
[   35.473502]  regmap_i2c_write+0x20/0x48 [regmap_i2c]
[   35.478659]  _regmap_raw_write_impl+0x780/0x944
[   35.483401]  _regmap_bus_raw_write+0x60/0x7c
[   35.487848]  _regmap_write+0x134/0x184
[   35.491773]  regmap_write+0x54/0x78
[   35.495418]  ps883x_set+0x58/0xec [ps883x]
[   35.499688]  ps883x_sw_set+0x60/0x84 [ps883x]
[   35.504223]  typec_switch_set+0x48/0x74 [typec]
[   35.508952]  pmic_glink_altmode_worker+0x44/0x1fc [pmic_glink_altmode]
[   35.515712]  process_scheduled_works+0x1a0/0x2d0
[   35.520525]  worker_thread+0x2a8/0x3c8
[   35.524449]  kthread+0xfc/0x184
[   35.527749]  ret_from_fork+0x10/0x20

The solution here is to schedule the altmode worker on the system_freezable_wq
instead of the system_wq. This will result in the altmode worker not being
scheduled to run until the devices are resumed first, which will give the
controllers like I2C a chance to resume before the transfer is requested.

Fixes: 080b4e24852b ("soc: qcom: pmic_glink: Introduce altmode support")
Cc: stable@...r.kernel.org    # 6.3
Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
---
 drivers/soc/qcom/pmic_glink_altmode.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/qcom/pmic_glink_altmode.c b/drivers/soc/qcom/pmic_glink_altmode.c
index bd06ce16180411059e9efb14d9aeccda27744280..bde129aa7d90a39becaa720376c0539bcaa492fb 100644
--- a/drivers/soc/qcom/pmic_glink_altmode.c
+++ b/drivers/soc/qcom/pmic_glink_altmode.c
@@ -295,7 +295,7 @@ static void pmic_glink_altmode_sc8180xp_notify(struct pmic_glink_altmode *altmod
 	alt_port->mode = mode;
 	alt_port->hpd_state = hpd_state;
 	alt_port->hpd_irq = hpd_irq;
-	schedule_work(&alt_port->work);
+	queue_work(system_freezable_wq, &alt_port->work);
 }
 
 #define SC8280XP_DPAM_MASK	0x3f
@@ -338,7 +338,7 @@ static void pmic_glink_altmode_sc8280xp_notify(struct pmic_glink_altmode *altmod
 	alt_port->mode = mode;
 	alt_port->hpd_state = hpd_state;
 	alt_port->hpd_irq = hpd_irq;
-	schedule_work(&alt_port->work);
+	queue_work(system_freezable_wq, &alt_port->work);
 }
 
 static void pmic_glink_altmode_callback(const void *data, size_t len, void *priv)

---
base-commit: 2b88851f583d3c4e40bcd40cfe1965241ec229dd
change-id: 20250110-soc-qcom-pmic-glink-fix-device-access-on-worker-while-suspended-af54c5e43ed6

Best regards,
-- 
Abel Vesa <abel.vesa@...aro.org>