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Message-ID: <6f183ff4-f23e-b82a-3524-2d1f5d833a2d@suse.cz>
Date: Wed, 19 Apr 2023 10:03:17 +0200
From: Vlastimil Babka <vbabka@...e.cz>
To: Qi Zheng <zhengqi.arch@...edance.com>,
Zqiang <qiang1.zhang@...el.com>, elver@...gle.com,
ryabinin.a.a@...il.com, glider@...gle.com, andreyknvl@...il.com,
dvyukov@...gle.com, akpm@...ux-foundation.org
Cc: kasan-dev@...glegroups.com, linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] kasan: Fix lockdep report invalid wait context
On 4/19/23 04:52, Qi Zheng wrote:
>
>
> On 2023/3/27 20:00, Zqiang wrote:
>> For kernels built with the following options and booting
>>
>> CONFIG_SLUB=y
>> CONFIG_DEBUG_LOCKDEP=y
>> CONFIG_PROVE_LOCKING=y
>> CONFIG_PROVE_RAW_LOCK_NESTING=y
>>
>> [ 0.523115] [ BUG: Invalid wait context ]
>> [ 0.523315] 6.3.0-rc1-yocto-standard+ #739 Not tainted
>> [ 0.523649] -----------------------------
>> [ 0.523663] swapper/0/0 is trying to lock:
>> [ 0.523663] ffff888035611360 (&c->lock){....}-{3:3}, at: put_cpu_partial+0x2e/0x1e0
>> [ 0.523663] other info that might help us debug this:
>> [ 0.523663] context-{2:2}
>> [ 0.523663] no locks held by swapper/0/0.
>> [ 0.523663] stack backtrace:
>> [ 0.523663] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.3.0-rc1-yocto-standard+ #739
>> [ 0.523663] Call Trace:
>> [ 0.523663] <IRQ>
>> [ 0.523663] dump_stack_lvl+0x64/0xb0
>> [ 0.523663] dump_stack+0x10/0x20
>> [ 0.523663] __lock_acquire+0x6c4/0x3c10
>> [ 0.523663] lock_acquire+0x188/0x460
>> [ 0.523663] put_cpu_partial+0x5a/0x1e0
>> [ 0.523663] __slab_free+0x39a/0x520
>> [ 0.523663] ___cache_free+0xa9/0xc0
>> [ 0.523663] qlist_free_all+0x7a/0x160
>> [ 0.523663] per_cpu_remove_cache+0x5c/0x70
>> [ 0.523663] __flush_smp_call_function_queue+0xfc/0x330
>> [ 0.523663] generic_smp_call_function_single_interrupt+0x13/0x20
>> [ 0.523663] __sysvec_call_function+0x86/0x2e0
>> [ 0.523663] sysvec_call_function+0x73/0x90
>> [ 0.523663] </IRQ>
>> [ 0.523663] <TASK>
>> [ 0.523663] asm_sysvec_call_function+0x1b/0x20
>> [ 0.523663] RIP: 0010:default_idle+0x13/0x20
>> [ 0.523663] RSP: 0000:ffffffff83e07dc0 EFLAGS: 00000246
>> [ 0.523663] RAX: 0000000000000000 RBX: ffffffff83e1e200 RCX: ffffffff82a83293
>> [ 0.523663] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8119a6b1
>> [ 0.523663] RBP: ffffffff83e07dc8 R08: 0000000000000001 R09: ffffed1006ac0d66
>> [ 0.523663] R10: ffff888035606b2b R11: ffffed1006ac0d65 R12: 0000000000000000
>> [ 0.523663] R13: ffffffff83e1e200 R14: ffffffff84a7d980 R15: 0000000000000000
>> [ 0.523663] default_idle_call+0x6c/0xa0
>> [ 0.523663] do_idle+0x2e1/0x330
>> [ 0.523663] cpu_startup_entry+0x20/0x30
>> [ 0.523663] rest_init+0x152/0x240
>> [ 0.523663] arch_call_rest_init+0x13/0x40
>> [ 0.523663] start_kernel+0x331/0x470
>> [ 0.523663] x86_64_start_reservations+0x18/0x40
>> [ 0.523663] x86_64_start_kernel+0xbb/0x120
>> [ 0.523663] secondary_startup_64_no_verify+0xe0/0xeb
>> [ 0.523663] </TASK>
>>
>> The local_lock_irqsave() is invoked in put_cpu_partial() and happens
>> in IPI context, due to the CONFIG_PROVE_RAW_LOCK_NESTING=y (the
>> LD_WAIT_CONFIG not equal to LD_WAIT_SPIN), so acquire local_lock in
>> IPI context will trigger above calltrace.
>
> Just to add another similar case:
>
> Call Trace:
> <IRQ>
> dump_stack_lvl+0x69/0x97
> __lock_acquire+0x4a0/0x1b50
> lock_acquire+0x261/0x2c0
> ? restore_bytes+0x40/0x40
> local_lock_acquire+0x21/0x70
> ? restore_bytes+0x40/0x40
> put_cpu_partial+0x41/0x130
> ? flush_smp_call_function_queue+0x125/0x4d0
> kfree+0x250/0x2c0
> flush_smp_call_function_queue+0x125/0x4d0
> __sysvec_call_function_single+0x3a/0x100
> sysvec_call_function_single+0x4b/0x90
> </IRQ>
> <TASK>
> asm_sysvec_call_function_single+0x16/0x20
>
> So we can't call kfree() and its friends in interrupt context?
We can (well not RT "hard IRQ" context AFAIK, but that shouldn't be the case
here), although I don't see from the part that you posted if it's again
CONFIG_PROVE_RAW_LOCK_NESTING clashing with something else (no KASAN in the
trace or I'm missing it?)
> Also +Vlastimil Babka.
>
> Thanks,
> Qi
>
>>
>> This commit therefore move qlist_free_all() from hard-irq context to
>> task context.
>>
>> Signed-off-by: Zqiang <qiang1.zhang@...el.com>
>> ---
>> v1->v2:
>> Modify the commit information and add Cc.
>>
>> mm/kasan/quarantine.c | 34 ++++++++--------------------------
>> 1 file changed, 8 insertions(+), 26 deletions(-)
>>
>> diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
>> index 75585077eb6d..152dca73f398 100644
>> --- a/mm/kasan/quarantine.c
>> +++ b/mm/kasan/quarantine.c
>> @@ -99,7 +99,6 @@ static unsigned long quarantine_size;
>> static DEFINE_RAW_SPINLOCK(quarantine_lock);
>> DEFINE_STATIC_SRCU(remove_cache_srcu);
>>
>> -#ifdef CONFIG_PREEMPT_RT
>> struct cpu_shrink_qlist {
>> raw_spinlock_t lock;
>> struct qlist_head qlist;
>> @@ -108,7 +107,6 @@ struct cpu_shrink_qlist {
>> static DEFINE_PER_CPU(struct cpu_shrink_qlist, shrink_qlist) = {
>> .lock = __RAW_SPIN_LOCK_UNLOCKED(shrink_qlist.lock),
>> };
>> -#endif
>>
>> /* Maximum size of the global queue. */
>> static unsigned long quarantine_max_size;
>> @@ -319,16 +317,6 @@ static void qlist_move_cache(struct qlist_head *from,
>> }
>> }
>>
>> -#ifndef CONFIG_PREEMPT_RT
>> -static void __per_cpu_remove_cache(struct qlist_head *q, void *arg)
>> -{
>> - struct kmem_cache *cache = arg;
>> - struct qlist_head to_free = QLIST_INIT;
>> -
>> - qlist_move_cache(q, &to_free, cache);
>> - qlist_free_all(&to_free, cache);
>> -}
>> -#else
>> static void __per_cpu_remove_cache(struct qlist_head *q, void *arg)
>> {
>> struct kmem_cache *cache = arg;
>> @@ -340,7 +328,6 @@ static void __per_cpu_remove_cache(struct qlist_head *q, void *arg)
>> qlist_move_cache(q, &sq->qlist, cache);
>> raw_spin_unlock_irqrestore(&sq->lock, flags);
>> }
>> -#endif
>>
>> static void per_cpu_remove_cache(void *arg)
>> {
>> @@ -362,6 +349,8 @@ void kasan_quarantine_remove_cache(struct kmem_cache *cache)
>> {
>> unsigned long flags, i;
>> struct qlist_head to_free = QLIST_INIT;
>> + int cpu;
>> + struct cpu_shrink_qlist *sq;
>>
>> /*
>> * Must be careful to not miss any objects that are being moved from
>> @@ -372,20 +361,13 @@ void kasan_quarantine_remove_cache(struct kmem_cache *cache)
>> */
>> on_each_cpu(per_cpu_remove_cache, cache, 1);
>>
>> -#ifdef CONFIG_PREEMPT_RT
>> - {
>> - int cpu;
>> - struct cpu_shrink_qlist *sq;
>> -
>> - for_each_online_cpu(cpu) {
>> - sq = per_cpu_ptr(&shrink_qlist, cpu);
>> - raw_spin_lock_irqsave(&sq->lock, flags);
>> - qlist_move_cache(&sq->qlist, &to_free, cache);
>> - raw_spin_unlock_irqrestore(&sq->lock, flags);
>> - }
>> - qlist_free_all(&to_free, cache);
>> + for_each_online_cpu(cpu) {
>> + sq = per_cpu_ptr(&shrink_qlist, cpu);
>> + raw_spin_lock_irqsave(&sq->lock, flags);
>> + qlist_move_cache(&sq->qlist, &to_free, cache);
>> + raw_spin_unlock_irqrestore(&sq->lock, flags);
>> }
>> -#endif
>> + qlist_free_all(&to_free, cache);
>>
>> raw_spin_lock_irqsave(&quarantine_lock, flags);
>> for (i = 0; i < QUARANTINE_BATCHES; i++) {
>
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