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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Jeremy Linton <jeremy.linton@arm.com>
Cc: linux-efi <linux-efi@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 5/5] efi: permit calling efi_mem_reserve_persistent from atomic context
Date: Tue, 27 Nov 2018 20:16:47 +0100
Message-ID: <CAKv+Gu8HFq0EnQv6PBVXqO5=WCBqA=ztwb+-otrpBz+J9SnHfA@mail.gmail.com> (raw)
In-Reply-To: <a8346212-70cb-0bbb-9e29-e21fa2ee5040@arm.com>

On Tue, 27 Nov 2018 at 19:59, Jeremy Linton <jeremy.linton@arm.com> wrote:
>
> Hi Ard,
>
>
> On 11/14/2018 11:55 AM, Ard Biesheuvel wrote:
> > Currently, efi_mem_reserve_persistent() may not be called from atomic
> > context, since both the kmalloc() call and the memremap() call may
> > sleep.
> >
> > The kmalloc() call is easy enough to fix, but the memremap() call
> > needs to be moved into an init hook since we cannot control the
> > memory allocation behavior of memremap() at the call site.
>
> So, at first glance this looks correct until I noticed that
> its_cpu_init_lpis() is being called before the early_initcalls are run.
>
> This results in the WARN_ON triggering with the following backtrace:
>
> [    0.000000]  its_cpu_init_lpis+0x1d4/0x2e0
> [    0.000000]  its_cpu_init+0x78/0x1b4
> [    0.000000]  gic_init_bases+0x2c4/0x2e0
> [    0.000000]  gic_acpi_init+0x158/0x270
> [    0.000000]  acpi_match_madt+0x4c/0x84
> [    0.000000]  acpi_table_parse_entries_array+0x140/0x218
> [    0.000000]  acpi_table_parse_entries+0x70/0x98
> [    0.000000]  acpi_table_parse_madt+0x40/0x50
> [    0.000000]  __acpi_probe_device_table+0x88/0xe0
> [    0.000000]  irqchip_init+0x38/0x40
> [    0.000000]  init_IRQ+0xfc/0x130
> [    0.000000]  start_kernel+0x344/0x4cc
>
> due to the efi_memreserve_root not yet being set.
>

Yup

https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?h=efi/urgent&id=976b489120cdab2b1b3a41ffa14661db43d58190

That should fix it. Please let me know if it doesn't work for you

      reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-14 17:55 [GIT PULL 0/5] EFI fixes for v4.20 Ard Biesheuvel
2018-11-14 17:55 ` [PATCH 1/5] efi: Fix debugobjects warning on efi_rts_work Ard Biesheuvel
2018-11-14 17:55 ` [PATCH 2/5] efi: arm: revert deferred unmap of early memmap mapping Ard Biesheuvel
2018-11-14 17:55 ` [PATCH 3/5] efi/arm: libstub: pack FDT after populating it Ard Biesheuvel
2018-11-14 17:55 ` [PATCH 4/5] efi/arm: defer persistent reservations until after paging_init() Ard Biesheuvel
2018-11-14 17:55 ` [PATCH 5/5] efi: permit calling efi_mem_reserve_persistent from atomic context Ard Biesheuvel
2018-11-27 18:59   ` Jeremy Linton
2018-11-27 19:16     ` Ard Biesheuvel [this message]

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