Messages in this thread | | | Date | Tue, 18 Oct 2022 15:07:49 +0200 | Subject | Re: [PATCH v2] firmware: arm_sdei: Fix sleep from invalid context BUG | From | Pierre Gondois <> |
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The changelog was removed:
v2: - Don't use a raw spin_lock, but move the CPUHP_AP_ARM_SDEI_ cpuhp state to the _ONLINE section.
On 10/18/22 15:04, Pierre Gondois wrote: > On an Ampere Altra, > Running a preemp_rt kernel based on v5.19-rc3-rt5 on an > Ampere Altra triggers: > [ 15.683141] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46 > [ 15.683154] in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 24, name: cpuhp/0 > [ 15.683157] preempt_count: 0, expected: 0 > [ 15.683159] RCU nest depth: 0, expected: 0 > [ 15.683163] 3 locks held by cpuhp/0/24: > [ 15.683167] #0: ffffda30217c70d0 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 > [ 15.683201] #1: ffffda30217c7120 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x5c/0x248 > [ 15.683205] #2: ffffda3021c711f0 (sdei_list_lock){....}-{3:3}, at: sdei_cpuhp_up+0x3c/0x130 > [ 15.683224] irq event stamp: 36 > [ 15.683226] hardirqs last enabled at (35): [<ffffda301e85b7bc>] finish_task_switch+0xb4/0x2b0 > [ 15.683236] hardirqs last disabled at (36): [<ffffda301e812fec>] cpuhp_thread_fun+0x21c/0x248 > [ 15.683238] softirqs last enabled at (0): [<ffffda301e80b184>] copy_process+0x63c/0x1ac0 > [ 15.683245] softirqs last disabled at (0): [<0000000000000000>] 0x0 > [ 15.683258] CPU: 0 PID: 24 Comm: cpuhp/0 Not tainted 5.19.0-rc3-rt5-[...] > [ 15.683265] Hardware name: WIWYNN Mt.Jade Server System B81.03001.0005/Mt.Jade Motherboard, BIOS 1.08.20220218 (SCP: 1.08.20220218) 2022/02/18 > [ 15.683268] Call trace: > [ 15.683271] dump_backtrace+0x114/0x120 > [ 15.683277] show_stack+0x20/0x70 > [ 15.683279] dump_stack_lvl+0x9c/0xd8 > [ 15.683288] dump_stack+0x18/0x34 > [ 15.683289] __might_resched+0x188/0x228 > [ 15.683292] rt_spin_lock+0x70/0x120 > [ 15.683301] sdei_cpuhp_up+0x3c/0x130 > [ 15.683303] cpuhp_invoke_callback+0x250/0xf08 > [ 15.683305] cpuhp_thread_fun+0x120/0x248 > [ 15.683308] smpboot_thread_fn+0x280/0x320 > [ 15.683315] kthread+0x130/0x140 > [ 15.683321] ret_from_fork+0x10/0x20 > > sdei_cpuhp_up() is called in the STARTING hotplug section, > which runs whith interrupts disabled. Move CPUHP_AP_ARM_SDEI_ > state to the _ONLINE section to execute the cpuhp cb with > preemption enabled. > > 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. This means that no check will be done for some > cases, e.g. sdei_mask_local_cpu() invocations. > > Also add a check for the SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI call > which acts on the calling CPU. > > Suggested-by: James Morse <james.morse@arm.com> > Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> > --- > drivers/firmware/arm_sdei.c | 28 ++++++++++++++-------------- > include/linux/cpuhotplug.h | 2 +- > 2 files changed, 15 insertions(+), 15 deletions(-) > > diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c > index 1e1a51510e83..9b03e164a37a 100644 > --- a/drivers/firmware/arm_sdei.c > +++ b/drivers/firmware/arm_sdei.c > @@ -301,8 +301,6 @@ 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", > @@ -315,6 +313,7 @@ int sdei_mask_local_cpu(void) > > static void _ipi_mask_cpu(void *ignored) > { > + WARN_ON_ONCE(preemptible()); > sdei_mask_local_cpu(); > } > > @@ -322,8 +321,6 @@ 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", > @@ -336,6 +333,7 @@ int sdei_unmask_local_cpu(void) > > static void _ipi_unmask_cpu(void *ignored) > { > + WARN_ON_ONCE(preemptible()); > sdei_unmask_local_cpu(); > } > > @@ -343,6 +341,8 @@ 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) > @@ -389,8 +389,6 @@ 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); > @@ -401,6 +399,8 @@ int sdei_event_enable(u32 event_num) > int err = -EINVAL; > struct sdei_event *event; > > + WARN_ON_ONCE(preemptible()); > + > mutex_lock(&sdei_events_lock); > event = sdei_event_find(event_num); > if (!event) { > @@ -479,8 +479,6 @@ 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); > @@ -492,6 +490,7 @@ int sdei_event_unregister(u32 event_num) > struct sdei_event *event; > > WARN_ON(in_nmi()); > + WARN_ON_ONCE(preemptible()); > > mutex_lock(&sdei_events_lock); > event = sdei_event_find(event_num); > @@ -561,8 +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); > @@ -576,6 +573,7 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg) > struct sdei_event *event; > > WARN_ON(in_nmi()); > + WARN_ON_ONCE(preemptible()); > > mutex_lock(&sdei_events_lock); > if (sdei_event_find(event_num)) { > @@ -717,6 +715,8 @@ 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(); > @@ -765,7 +765,7 @@ static int sdei_device_freeze(struct device *dev) > int err; > > /* unregister private events */ > - cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING); > + cpuhp_remove_state(CPUHP_AP_ARM_SDEI_ONLINE); > > err = sdei_unregister_shared(); > if (err) > @@ -786,7 +786,7 @@ 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_ARM_SDEI_ONLINE, "SDEI", > &sdei_cpuhp_up, &sdei_cpuhp_down); > if (err) > pr_warn("Failed to re-register CPU hotplug notifier...\n"); > @@ -823,7 +823,7 @@ 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(CPUHP_AP_ARM_SDEI_ONLINE); > > sdei_platform_reset(); > > @@ -1003,7 +1003,7 @@ 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_ARM_SDEI_ONLINE, "SDEI", > &sdei_cpuhp_up, &sdei_cpuhp_down); > if (err) { > pr_warn("Failed to register CPU hotplug notifier...\n"); > diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h > index f61447913db9..63b89e00a4c3 100644 > --- a/include/linux/cpuhotplug.h > +++ b/include/linux/cpuhotplug.h > @@ -161,7 +161,6 @@ 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, > @@ -209,6 +208,7 @@ enum cpuhp_state { > CPUHP_AP_IRQ_AFFINITY_ONLINE, > CPUHP_AP_BLK_MQ_ONLINE, > CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS, > + CPUHP_AP_ARM_SDEI_ONLINE, > CPUHP_AP_X86_INTEL_EPB_ONLINE, > CPUHP_AP_PERF_ONLINE, > CPUHP_AP_PERF_X86_ONLINE,
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