* [PATCH 1/1] iommu/vt-d: Avoid memory allocation in iommu_suspend()
2023-09-25 12:04 [PATCH 0/1] [PULL REQUEST] iommu/vt-d: Fixes for v6.6-rc4 Lu Baolu
@ 2023-09-25 12:04 ` Lu Baolu
2023-09-25 14:31 ` [PATCH 0/1] [PULL REQUEST] iommu/vt-d: Fixes for v6.6-rc4 Joerg Roedel
1 sibling, 0 replies; 3+ messages in thread
From: Lu Baolu @ 2023-09-25 12:04 UTC (permalink / raw)
To: Joerg Roedel; +Cc: Zhang Rui, iommu, linux-kernel
From: Zhang Rui <rui.zhang@intel.com>
The iommu_suspend() syscore suspend callback is invoked with IRQ disabled.
Allocating memory with the GFP_KERNEL flag may re-enable IRQs during
the suspend callback, which can cause intermittent suspend/hibernation
problems with the following kernel traces:
Calling iommu_suspend+0x0/0x1d0
------------[ cut here ]------------
WARNING: CPU: 0 PID: 15 at kernel/time/timekeeping.c:868 ktime_get+0x9b/0xb0
...
CPU: 0 PID: 15 Comm: rcu_preempt Tainted: G U E 6.3-intel #r1
RIP: 0010:ktime_get+0x9b/0xb0
...
Call Trace:
<IRQ>
tick_sched_timer+0x22/0x90
? __pfx_tick_sched_timer+0x10/0x10
__hrtimer_run_queues+0x111/0x2b0
hrtimer_interrupt+0xfa/0x230
__sysvec_apic_timer_interrupt+0x63/0x140
sysvec_apic_timer_interrupt+0x7b/0xa0
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1f/0x30
...
------------[ cut here ]------------
Interrupts enabled after iommu_suspend+0x0/0x1d0
WARNING: CPU: 0 PID: 27420 at drivers/base/syscore.c:68 syscore_suspend+0x147/0x270
CPU: 0 PID: 27420 Comm: rtcwake Tainted: G U W E 6.3-intel #r1
RIP: 0010:syscore_suspend+0x147/0x270
...
Call Trace:
<TASK>
hibernation_snapshot+0x25b/0x670
hibernate+0xcd/0x390
state_store+0xcf/0xe0
kobj_attr_store+0x13/0x30
sysfs_kf_write+0x3f/0x50
kernfs_fop_write_iter+0x128/0x200
vfs_write+0x1fd/0x3c0
ksys_write+0x6f/0xf0
__x64_sys_write+0x1d/0x30
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
Given that only 4 words memory is needed, avoid the memory allocation in
iommu_suspend().
CC: stable@kernel.org
Fixes: 33e07157105e ("iommu/vt-d: Avoid GFP_ATOMIC where it is not needed")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Tested-by: Ooi, Chin Hao <chin.hao.ooi@intel.com>
Link: https://lore.kernel.org/r/20230921093956.234692-1-rui.zhang@intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel/iommu.h | 2 +-
drivers/iommu/intel/iommu.c | 16 ----------------
2 files changed, 1 insertion(+), 17 deletions(-)
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index c18fb699c87a..7dac94f62b4e 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -681,7 +681,7 @@ struct intel_iommu {
struct iopf_queue *iopf_queue;
unsigned char iopfq_name[16];
struct q_inval *qi; /* Queued invalidation info */
- u32 *iommu_state; /* Store iommu states between suspend and resume.*/
+ u32 iommu_state[MAX_SR_DMAR_REGS]; /* Store iommu states between suspend and resume.*/
#ifdef CONFIG_IRQ_REMAP
struct ir_table *ir_table; /* Interrupt remapping info */
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 5db283c17e0d..3685ba90ec88 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2998,13 +2998,6 @@ static int iommu_suspend(void)
struct intel_iommu *iommu = NULL;
unsigned long flag;
- for_each_active_iommu(iommu, drhd) {
- iommu->iommu_state = kcalloc(MAX_SR_DMAR_REGS, sizeof(u32),
- GFP_KERNEL);
- if (!iommu->iommu_state)
- goto nomem;
- }
-
iommu_flush_all();
for_each_active_iommu(iommu, drhd) {
@@ -3024,12 +3017,6 @@ static int iommu_suspend(void)
raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
}
return 0;
-
-nomem:
- for_each_active_iommu(iommu, drhd)
- kfree(iommu->iommu_state);
-
- return -ENOMEM;
}
static void iommu_resume(void)
@@ -3061,9 +3048,6 @@ static void iommu_resume(void)
raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
}
-
- for_each_active_iommu(iommu, drhd)
- kfree(iommu->iommu_state);
}
static struct syscore_ops iommu_syscore_ops = {
--
2.34.1
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