[PATCH AUTOSEL 5.10 05/12] firmware: arm_sdei: Fix sleep from invalid context BUG

[PATCH AUTOSEL 5.10 05/12] firmware: arm_sdei: Fix sleep from invalid context BUG

[Sasha Levin]

From: Pierre Gondois <pierre.gondois@arm.com>

[ Upstream commit d2c48b2387eb89e0bf2a2e06e30987cf410acad4 ]

Running a preempt-rt (v6.2-rc3-rt1) based kernel on an Ampere Altra
triggers:

  BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
  in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 24, name: cpuhp/0
  preempt_count: 0, expected: 0
  RCU nest depth: 0, expected: 0
  3 locks held by cpuhp/0/24:
    #0: ffffda30217c70d0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248
    #1: ffffda30217c7120 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248
    #2: ffffda3021c711f0 (sdei_list_lock){....}-{3:3}, at: sdei_cpuhp_up+0x3c/0x130
  irq event stamp: 36
  hardirqs last  enabled at (35): [<ffffda301e85b7bc>] finish_task_switch+0xb4/0x2b0
  hardirqs last disabled at (36): [<ffffda301e812fec>] cpuhp_thread_fun+0x21c/0x248
  softirqs last  enabled at (0): [<ffffda301e80b184>] copy_process+0x63c/0x1ac0
  softirqs last disabled at (0): [<0000000000000000>] 0x0
  CPU: 0 PID: 24 Comm: cpuhp/0 Not tainted 5.19.0-rc3-rt5-[...]
  Hardware name: WIWYNN Mt.Jade Server [...]
  Call trace:
    dump_backtrace+0x114/0x120
    show_stack+0x20/0x70
    dump_stack_lvl+0x9c/0xd8
    dump_stack+0x18/0x34
    __might_resched+0x188/0x228
    rt_spin_lock+0x70/0x120
    sdei_cpuhp_up+0x3c/0x130
    cpuhp_invoke_callback+0x250/0xf08
    cpuhp_thread_fun+0x120/0x248
    smpboot_thread_fn+0x280/0x320
    kthread+0x130/0x140
    ret_from_fork+0x10/0x20

sdei_cpuhp_up() is called in the STARTING hotplug section,
which runs with interrupts disabled. Use a CPUHP_AP_ONLINE_DYN entry
instead to execute the cpuhp cb later, with preemption enabled.

SDEI originally got its own cpuhp slot to allow interacting
with perf. It got superseded by pNMI and this early slot is not
relevant anymore. [1]

Some SDEI calls (e.g. SDEI_1_0_FN_SDEI_PE_MASK) take actions on the
calling CPU. It is checked that preemption is disabled for them.
_ONLINE cpuhp cb are executed in the 'per CPU hotplug thread'.
Preemption is enabled in those threads, but their cpumask is limited
to 1 CPU.
Move 'WARN_ON_ONCE(preemptible())' statements so that SDEI cpuhp cb
don't trigger them.

Also add a check for the SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI call
which acts on the calling CPU.

[1]:
https://lore.kernel.org/all/5813b8c5-ae3e-87fd-fccc-94c9cd08816d@arm.com/

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Link: https://lore.kernel.org/r/20230216084920.144064-1-pierre.gondois@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/firmware/arm_sdei.c | 37 ++++++++++++++++++++-----------------
 include/linux/cpuhotplug.h  |  1 -
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index 840754dcc6ca4..5a877d76078f7 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c
@@ -44,6 +44,8 @@ static asmlinkage void (*sdei_firmware_call)(unsigned long function_id,
 /* entry point from firmware to arch asm code */
 static unsigned long sdei_entry_point;
 
+static int sdei_hp_state;
+
 struct sdei_event {
 	/* These three are protected by the sdei_list_lock */
 	struct list_head	list;
@@ -302,8 +304,6 @@ int sdei_mask_local_cpu(void)
 {
 	int err;
 
-	WARN_ON_ONCE(preemptible());
-
 	err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_MASK, 0, 0, 0, 0, 0, NULL);
 	if (err && err != -EIO) {
 		pr_warn_once("failed to mask CPU[%u]: %d\n",
@@ -316,6 +316,7 @@ int sdei_mask_local_cpu(void)
 
 static void _ipi_mask_cpu(void *ignored)
 {
+	WARN_ON_ONCE(preemptible());
 	sdei_mask_local_cpu();
 }
 
@@ -323,8 +324,6 @@ int sdei_unmask_local_cpu(void)
 {
 	int err;
 
-	WARN_ON_ONCE(preemptible());
-
 	err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_UNMASK, 0, 0, 0, 0, 0, NULL);
 	if (err && err != -EIO) {
 		pr_warn_once("failed to unmask CPU[%u]: %d\n",
@@ -337,6 +336,7 @@ int sdei_unmask_local_cpu(void)
 
 static void _ipi_unmask_cpu(void *ignored)
 {
+	WARN_ON_ONCE(preemptible());
 	sdei_unmask_local_cpu();
 }
 
@@ -344,6 +344,8 @@ static void _ipi_private_reset(void *ignored)
 {
 	int err;
 
+	WARN_ON_ONCE(preemptible());
+
 	err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PRIVATE_RESET, 0, 0, 0, 0, 0,
 			     NULL);
 	if (err && err != -EIO)
@@ -390,8 +392,6 @@ static void _local_event_enable(void *data)
 	int err;
 	struct sdei_crosscall_args *arg = data;
 
-	WARN_ON_ONCE(preemptible());
-
 	err = sdei_api_event_enable(arg->event->event_num);
 
 	sdei_cross_call_return(arg, err);
@@ -480,8 +480,6 @@ static void _local_event_unregister(void *data)
 	int err;
 	struct sdei_crosscall_args *arg = data;
 
-	WARN_ON_ONCE(preemptible());
-
 	err = sdei_api_event_unregister(arg->event->event_num);
 
 	sdei_cross_call_return(arg, err);
@@ -562,8 +560,6 @@ static void _local_event_register(void *data)
 	struct sdei_registered_event *reg;
 	struct sdei_crosscall_args *arg = data;
 
-	WARN_ON(preemptible());
-
 	reg = per_cpu_ptr(arg->event->private_registered, smp_processor_id());
 	err = sdei_api_event_register(arg->event->event_num, sdei_entry_point,
 				      reg, 0, 0);
@@ -718,6 +714,8 @@ static int sdei_pm_notifier(struct notifier_block *nb, unsigned long action,
 {
 	int rv;
 
+	WARN_ON_ONCE(preemptible());
+
 	switch (action) {
 	case CPU_PM_ENTER:
 		rv = sdei_mask_local_cpu();
@@ -766,7 +764,7 @@ static int sdei_device_freeze(struct device *dev)
 	int err;
 
 	/* unregister private events */
-	cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING);
+	cpuhp_remove_state(sdei_entry_point);
 
 	err = sdei_unregister_shared();
 	if (err)
@@ -787,12 +785,15 @@ static int sdei_device_thaw(struct device *dev)
 		return err;
 	}
 
-	err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI",
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SDEI",
 				&sdei_cpuhp_up, &sdei_cpuhp_down);
-	if (err)
+	if (err < 0) {
 		pr_warn("Failed to re-register CPU hotplug notifier...\n");
+		return err;
+	}
 
-	return err;
+	sdei_hp_state = err;
+	return 0;
 }
 
 static int sdei_device_restore(struct device *dev)
@@ -824,7 +825,7 @@ static int sdei_reboot_notifier(struct notifier_block *nb, unsigned long action,
 	 * We are going to reset the interface, after this there is no point
 	 * doing work when we take CPUs offline.
 	 */
-	cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING);
+	cpuhp_remove_state(sdei_hp_state);
 
 	sdei_platform_reset();
 
@@ -1004,13 +1005,15 @@ static int sdei_probe(struct platform_device *pdev)
 		goto remove_cpupm;
 	}
 
-	err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI",
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SDEI",
 				&sdei_cpuhp_up, &sdei_cpuhp_down);
-	if (err) {
+	if (err < 0) {
 		pr_warn("Failed to register CPU hotplug notifier...\n");
 		goto remove_reboot;
 	}
 
+	sdei_hp_state = err;
+
 	return 0;
 
 remove_reboot:
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index fc945f9df2c1d..cb87247da5ba1 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -115,7 +115,6 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_X86_CSTATE_STARTING,
 	CPUHP_AP_PERF_XTENSA_STARTING,
 	CPUHP_AP_MIPS_OP_LOONGSON3_STARTING,
-	CPUHP_AP_ARM_SDEI_STARTING,
 	CPUHP_AP_ARM_VFP_STARTING,
 	CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING,
 	CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING,
-- 
2.39.2


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[PATCH AUTOSEL 5.10 07/12] remoteproc: stm32_rproc: Add mutex protection for workqueue

[Sasha Levin]

From: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>

[ Upstream commit 35bdafda40cc343ad2ba2cce105eba03a70241cc ]

The workqueue may execute late even after remoteproc is stopped or
stopping, some resources (rpmsg device and endpoint) have been
released in rproc_stop_subdevices(), then rproc_vq_interrupt()
accessing these resources will cause kernel dump.

Call trace:
virtqueue_add_inbuf
virtqueue_add_inbuf
rpmsg_recv_single
rpmsg_recv_done
vring_interrupt
stm32_rproc_mb_vq_work
process_one_work
worker_thread
kthread

Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/20230331160634.3113031-1-arnaud.pouliquen@foss.st.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/remoteproc/stm32_rproc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
index d2414cc1d90d6..659b747e182d5 100644
--- a/drivers/remoteproc/stm32_rproc.c
+++ b/drivers/remoteproc/stm32_rproc.c
@@ -297,8 +297,16 @@ static void stm32_rproc_mb_vq_work(struct work_struct *work)
 	struct stm32_mbox *mb = container_of(work, struct stm32_mbox, vq_work);
 	struct rproc *rproc = dev_get_drvdata(mb->client.dev);
 
+	mutex_lock(&rproc->lock);
+
+	if (rproc->state != RPROC_RUNNING)
+		goto unlock_mutex;
+
 	if (rproc_vq_interrupt(rproc, mb->vq_id) == IRQ_NONE)
 		dev_dbg(&rproc->dev, "no message found in vq%d\n", mb->vq_id);
+
+unlock_mutex:
+	mutex_unlock(&rproc->lock);
 }
 
 static void stm32_rproc_mb_callback(struct mbox_client *cl, void *data)
-- 
2.39.2


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