From: Mike Rapoport <rppt@linux.ibm.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Borislav Petkov <bp@suse.de>, Hugh Dickins <hughd@google.com>,
the arch/x86 maintainers <x86@kernel.org>
Subject: Re: [tip: x86/urgent] x86/setup: Always reserve the first 1M of RAM
Date: Fri, 3 Mar 2023 11:10:22 +0200 [thread overview]
Message-ID: <ZAG5fvRl4Z+3vGfS@linux.ibm.com> (raw)
In-Reply-To: <7d344756-aec4-4df2-9427-da742ef9ce6b@app.fastmail.com>
Hi Andy,
On Wed, Mar 01, 2023 at 07:51:43PM -0800, Andy Lutomirski wrote:
> On Thu, Jun 3, 2021, at 11:01 AM, tip-bot2 for Mike Rapoport wrote:
> >
> > x86/setup: Always reserve the first 1M of RAM
> >
...
> + /*
> + * Unconditionally reserve the entire fisrt 1M, see comment in
> + * setup_arch().
> + */
> + memblock_reserve(0, SZ_1M);
>
>
> But this runs even if we just failed to allocate a trampoline on the
> first try, again dooming the kernel to panic.
>
> I real the commit message and the linked bug, and I'm having trouble
> finding evidence of anything actually fixed by this patch. Can we just
> revert it? If not, it would be nice to get a fixup patch that genuinely
> cleans this up -- the whole structure of the code (first, try to allocate
> trampoline, then free boot services, then try again) isn't really
> conducive to a model where we *don't* free boot services < 1M.
Currently, the second attempt to set_real_mode_mem() in
efi_free_boot_services() does not allocate from memblock anyway but reuses
memory freed from EFI services. Could be that failure to boot caused by
another failing reservation?
> Discovered by my delightful laptop, which does not boot with this patch applied.
Do you have early_printk() visible?
> --Andy
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2023-03-03 9:10 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-01 7:53 [PATCH 0/3] x86/setup: always resrve the first 1M of RAM Mike Rapoport
2021-06-01 7:53 ` [PATCH 1/3] x86/setup: always reserve " Mike Rapoport
2021-06-01 9:06 ` Baoquan He
2021-06-01 17:19 ` Mike Rapoport
2021-06-03 17:57 ` Borislav Petkov
2021-06-03 18:01 ` [tip: x86/urgent] x86/setup: Always " tip-bot2 for Mike Rapoport
2023-03-02 3:51 ` Andy Lutomirski
2023-03-02 10:50 ` Borislav Petkov
2023-03-02 15:06 ` Andy Lutomirski
2023-03-02 15:22 ` Borislav Petkov
2023-03-02 16:59 ` Andy Lutomirski
2023-03-03 9:10 ` Mike Rapoport [this message]
2023-03-07 0:33 ` Andy Lutomirski
2021-07-01 17:15 ` [PATCH 1/3] x86/setup: always " Dave Hansen
2021-07-01 19:45 ` Mike Rapoport
2021-06-01 7:53 ` [PATCH 2/3] x86/setup: remove CONFIG_X86_RESERVE_LOW and reservelow options Mike Rapoport
2021-06-07 12:22 ` [tip: x86/cleanups] x86/setup: Remove CONFIG_X86_RESERVE_LOW and reservelow= options tip-bot2 for Mike Rapoport
2021-06-01 7:53 ` [PATCH 3/3] x86/crash: remove crash_reserve_low_1M() Mike Rapoport
2021-06-07 12:22 ` [tip: x86/cleanups] x86/crash: Remove crash_reserve_low_1M() tip-bot2 for Mike Rapoport
2021-06-01 18:10 ` [PATCH 0/3] x86/setup: always resrve the first 1M of RAM Hugh Dickins
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