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From: Catalin Marinas <catalin.marinas@arm.com>
To: Jianyong Wu <Jianyong.Wu@arm.com>
Cc: "will@kernel.org" <will@kernel.org>,
	Anshuman Khandual <Anshuman.Khandual@arm.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"david@redhat.com" <david@redhat.com>,
	"quic_qiancai@quicinc.com" <quic_qiancai@quicinc.com>,
	"ardb@kernel.org" <ardb@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	 "gshan@redhat.com" <gshan@redhat.com>,
	Justin He <Justin.He@arm.com>, nd <nd@arm.com>
Subject: Re: [PATCH v3] arm64/mm: avoid fixmap race condition when create pud mapping
Date: Fri, 7 Jan 2022 10:53:54 +0000	[thread overview]
Message-ID: <YdgbwpECTXGCJZ/0@arm.com> (raw)
In-Reply-To: <AM9PR08MB7276B412F02CA0431E30E06CF44D9@AM9PR08MB7276.eurprd08.prod.outlook.com>

On Fri, Jan 07, 2022 at 09:10:57AM +0000, Jianyong Wu wrote:
> I roughly find the root cause.
>  alloc_init_pud will be called at the very beginning of kernel boot in
>  create_mapping_noalloc where no memory allocator is initialized. But
>  lockdep check may need allocate memory. So, kernel take exception
>  when acquire lock.(I have not found the exact code that cause this
>  issue) that's say we may not be able to use a lock so early.

I couldn't find an slab or page allocation place either. It would be
nice to get to the root cause rather than just avoiding the mutex on the
early boot path.

-- 
Catalin

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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com>
To: Jianyong Wu <Jianyong.Wu@arm.com>
Cc: "will@kernel.org" <will@kernel.org>,
	Anshuman Khandual <Anshuman.Khandual@arm.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"david@redhat.com" <david@redhat.com>,
	"quic_qiancai@quicinc.com" <quic_qiancai@quicinc.com>,
	"ardb@kernel.org" <ardb@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"gshan@redhat.com" <gshan@redhat.com>,
	Justin He <Justin.He@arm.com>, nd <nd@arm.com>
Subject: Re: [PATCH v3] arm64/mm: avoid fixmap race condition when create pud mapping
Date: Fri, 7 Jan 2022 10:53:54 +0000	[thread overview]
Message-ID: <YdgbwpECTXGCJZ/0@arm.com> (raw)
In-Reply-To: <AM9PR08MB7276B412F02CA0431E30E06CF44D9@AM9PR08MB7276.eurprd08.prod.outlook.com>

On Fri, Jan 07, 2022 at 09:10:57AM +0000, Jianyong Wu wrote:
> I roughly find the root cause.
>  alloc_init_pud will be called at the very beginning of kernel boot in
>  create_mapping_noalloc where no memory allocator is initialized. But
>  lockdep check may need allocate memory. So, kernel take exception
>  when acquire lock.(I have not found the exact code that cause this
>  issue) that's say we may not be able to use a lock so early.

I couldn't find an slab or page allocation place either. It would be
nice to get to the root cause rather than just avoiding the mutex on the
early boot path.

-- 
Catalin

  parent reply	other threads:[~2022-01-07 10:55 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-16  8:28 [PATCH v3] arm64/mm: avoid fixmap race condition when create pud mapping Jianyong Wu
2021-12-16  8:28 ` Jianyong Wu
2021-12-16 15:19 ` David Hildenbrand
2021-12-16 15:19   ` David Hildenbrand
2021-12-17  9:30 ` Mark Rutland
2021-12-17  9:30   ` Mark Rutland
2021-12-17 10:09   ` Jianyong Wu
2021-12-17 10:09     ` Jianyong Wu
2022-01-05 18:03 ` Catalin Marinas
2022-01-05 18:03   ` Catalin Marinas
2022-01-06 10:13   ` Jianyong Wu
2022-01-06 10:13     ` Jianyong Wu
2022-01-06 15:56     ` Catalin Marinas
2022-01-06 15:56       ` Catalin Marinas
2022-01-07  9:10       ` Jianyong Wu
2022-01-07  9:10         ` Jianyong Wu
2022-01-07 10:42         ` Catalin Marinas
2022-01-07 10:42           ` Catalin Marinas
2022-01-26  4:20           ` Justin He
2022-01-26  4:20             ` Justin He
2022-01-26  8:36             ` Ard Biesheuvel
2022-01-26  8:36               ` Ard Biesheuvel
2022-01-26 10:09               ` Jianyong Wu
2022-01-26 10:09                 ` Jianyong Wu
2022-01-26 10:12                 ` Ard Biesheuvel
2022-01-26 10:12                   ` Ard Biesheuvel
2022-01-26 10:17                   ` David Hildenbrand
2022-01-26 10:17                     ` David Hildenbrand
2022-01-26 10:28                     ` Jianyong Wu
2022-01-26 10:28                       ` Jianyong Wu
2022-01-26 10:30                       ` David Hildenbrand
2022-01-26 10:30                         ` David Hildenbrand
2022-01-26 10:31                         ` David Hildenbrand
2022-01-26 10:31                           ` David Hildenbrand
2022-01-27  6:24                           ` Jianyong Wu
2022-01-27  6:24                             ` Jianyong Wu
2022-01-27 12:22                             ` David Hildenbrand
2022-01-27 12:22                               ` David Hildenbrand
2022-01-27 12:34                               ` Catalin Marinas
2022-01-27 12:34                                 ` Catalin Marinas
2022-01-31  8:13                                 ` Jianyong Wu
2022-01-31  8:13                                   ` Jianyong Wu
2022-01-31  8:10                               ` Jianyong Wu
2022-01-31  8:10                                 ` Jianyong Wu
2022-01-27  1:31               ` Justin He
2022-01-27  1:31                 ` Justin He
2022-01-07 10:53         ` Catalin Marinas [this message]
2022-01-07 10:53           ` Catalin Marinas

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