From: Chao Fan <fanc.fnst@cn.fujitsu.com>
To: Dave Young <dyoung@redhat.com>
Cc: Junichi Nomura <j-nomura@ce.jp.nec.com>,
Borislav Petkov <bp@alien8.de>, "bhe@redhat.com" <bhe@redhat.com>,
"kasong@redhat.com" <kasong@redhat.com>,
"x86@kernel.org" <x86@kernel.org>,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel
Date: Wed, 3 Apr 2019 16:23:06 +0800 [thread overview]
Message-ID: <20190403082305.GG1555@localhost.localdomain> (raw)
In-Reply-To: <20190403080846.GB2579@dhcp-128-65.nay.redhat.com>
On Wed, Apr 03, 2019 at 04:09:16PM +0800, Dave Young wrote:
>On 04/03/19 at 03:21pm, Chao Fan wrote:
>> On Wed, Apr 03, 2019 at 01:53:40PM +0800, Dave Young wrote:
>> >On 04/03/19 at 01:35pm, Chao Fan wrote:
>> >> On Tue, Apr 02, 2019 at 08:03:19PM +0800, Dave Young wrote:
>> >> >On 04/01/19 at 12:08am, Junichi Nomura wrote:
>> >> >> Commit 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in
>> >> >> boot_params") broke kexec boot on EFI systems. efi_get_rsdp_addr()
>> >> >> in the early parsing code tries to search RSDP from EFI table but
>> >> >> that will crash because the table address is virtual when the kernel
>> >> >> was booted by kexec.
>> >> >>
>> >> >> In the case of kexec, physical address of EFI tables is provided
>> >> >> via efi_setup_data in boot_params, which is set up by kexec(1).
>> >> >>
>> >> >> Factor out the table parsing code and use different pointers depending
>> >> >> on whether the kernel is booted by kexec or not.
>> >> >>
>> >> >> Fixes: 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in boot_params")
>> >> >> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
>> >> >> Acked-by: Baoquan He <bhe@redhat.com>
>> >> >> Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
>> >> >> Cc: Borislav Petkov <bp@suse.de>
>> >> >> Cc: Dave Young <dyoung@redhat.com>
>> >> [...]
>> >> >
>> >> >I failed to kexec reboot on my laptop, kernel panics too quick, I'm not sure this is
>> >> >caused by your patch though.
>> >> >
>> >> >Actually there are something probably i915 changes break kexec, the
>> >> >above test is with "nomodeset" which should work.
>> >> >
>> >> >Let me do more testing and update here tomorrow.
>> >> >
>> >>
>> >> Hi Dave,
>> >>
>> >> Last day I was testing the normal kexec, today I have tested the kdump
>> >> issue. Since the kdump has set "nokaslr" to cmdline, so I drop from
>> >> KDUMP_COMMANDLINE_APPEND
>> >> And it booted OK, so the PATCH works in both normal kexec and kdump.
>> >>
>> >
>> >Actually I got some different kexec test results.
>> >
>> >Yesterday, with my installed kernel (based on git head several weeks
>> >ago), kexec kernel panics.
>> >
>> >Then I tried latest mainline with git pull, everything works, (with or
>> >without the patch, and can not reproduce the bug this patch is fixing)
>> >
>> >Today, test again, kexec reboot hangs (with or without your patch), but
>> >kdump works always (with or without the patch)
>>
>> That's so strange, I'm puzzled by your test.
>> Withour ant changes, just test again, the result of yesterday and today
>> are different?
>>
>> >
>> >It is weird to me. Probably I need find out why I can not reproduce the
>> >bug this patch is addressing first.
>>
>> Hmm, is your laptop booted from EFI or legacy BIOS?
>
>EFI booted.
>
>> >
>> >earlyprintk seems not working for me anymore, it is not easy to debug on
>> >laptop now.
>>
>> Another computer can help print the console message.
>> I remeber you are good at debug on two computers.
>
>I used to use earlyprintk, but seems earlyprintk can not work so early.
>So I only can try to comment out code manually.
Ah, I got it. If you want to use earlyprintk to print message of
get_rsdp_addr(), you should change some code.
Because get_rsdp_addr() is called before earlyprintk initialed.
I am still testing, but in my debug stage, I change like this:
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index c0d6c560df69..dbbe8d9a5792 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -352,7 +352,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
boot_params->hdr.loadflags &= ~KASLR_FLAG;
/* Save RSDP address for later use. */
- boot_params->acpi_rsdp_addr = get_rsdp_addr();
sanitize_boot_params(boot_params);
@@ -368,6 +367,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
cols = boot_params->screen_info.orig_video_cols;
console_init();
+ boot_params->acpi_rsdp_addr = get_rsdp_addr();
debug_putstr("early console in extract_kernel\n");
free_mem_ptr = heap; /* Heap */
Call this function after console_init().
That will make earlyprintk works.
>
>It seems to be still some bug in early acpi code because if I
>return 0 in get rsdp function it just works.
>
>This guess make sense to me for now:
>1. nokaslr does not work because it may only avoid randomization, but it
>does not avoid running the early acpi parsing code.
>
>2. kexec does not work without the patch we talked about, because I just
>reproduced Junichi reported bug, sometimes hang, or reset, it is
>understandable.
>
>3. kexec does not work with the patch, so there is still bugs in the
>code.
>
>So several things to do is:
>
>Fix 1. (separate issue), Baoquan or either of you may want to fix it :)
For 1, I think it's not needed to fix. Since not only KASLR needs RSDP.
So nokaslr should not stop the acpi parsing code.
>
>Fix 3. need more debugging, have you or Junichi run tests on more real
>hardware, maybe it is easier to reproduce on real hardware, I'm glad to
>help to try test patch or provide any help.
I am still testing in real hardware.
Thanks,
Chao Fan
>
>Thanks
>Dave
>
>
next prev parent reply other threads:[~2019-04-03 8:23 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-22 11:03 [PATCH] x86/boot: Use EFI setup data if provided Junichi Nomura
2019-03-22 15:23 ` Borislav Petkov
2019-03-25 0:27 ` Junichi Nomura
2019-03-25 6:01 ` Dave Young
2019-03-25 6:19 ` Dave Young
2019-03-25 6:45 ` Kairui Song
2019-03-25 6:47 ` Junichi Nomura
2019-03-25 6:59 ` Dave Young
2019-03-25 8:27 ` [PATCH v2] " Junichi Nomura
2019-03-25 8:54 ` Boris Petkov
2019-03-25 9:25 ` [PATCH v2] x86/boot: Don't try to search RSDP from EFI when kexec-booted Junichi Nomura
2019-03-25 10:15 ` [PATCH v2] x86/boot: Use EFI setup data if provided Dave Young
2019-03-25 10:36 ` Junichi Nomura
2019-03-25 11:16 ` Dave Young
2019-03-25 12:01 ` Borislav Petkov
2019-03-25 12:23 ` Dave Young
2019-03-25 12:32 ` Borislav Petkov
2019-03-25 23:10 ` Junichi Nomura
2019-03-26 12:46 ` Dave Young
2019-03-26 13:57 ` Borislav Petkov
2019-03-27 1:48 ` bhe
2019-03-27 12:14 ` Borislav Petkov
2019-03-28 4:17 ` Junichi Nomura
2019-03-28 6:26 ` Chao Fan
2019-03-28 6:43 ` bhe
2019-03-28 7:43 ` Junichi Nomura
2019-03-28 15:52 ` Borislav Petkov
2019-03-29 3:05 ` Junichi Nomura
2019-03-29 8:39 ` Borislav Petkov
2019-03-29 9:05 ` Chao Fan
2019-03-29 9:16 ` Borislav Petkov
2019-03-29 9:37 ` Junichi Nomura
2019-03-29 9:44 ` Chao Fan
2019-03-29 9:56 ` Junichi Nomura
2019-03-29 7:20 ` [PATCH] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel Junichi Nomura
2019-03-29 7:49 ` bhe
2019-03-29 8:29 ` Chao Fan
2019-03-29 8:39 ` Junichi Nomura
2019-03-29 9:18 ` Chao Fan
2019-03-29 9:16 ` bhe
2019-03-29 9:20 ` Chao Fan
2019-04-01 0:08 ` [PATCH v2] " Junichi Nomura
2019-04-02 9:41 ` Chao Fan
2019-04-02 9:53 ` Junichi Nomura
2019-04-02 11:06 ` Chao Fan
2019-04-02 10:22 ` Junichi Nomura
2019-04-02 12:03 ` Dave Young
2019-04-03 5:35 ` Chao Fan
2019-04-03 5:53 ` Dave Young
2019-04-03 6:39 ` Dave Young
2019-04-03 7:30 ` Chao Fan
2019-04-03 7:50 ` bhe
2019-04-03 8:23 ` Dave Young
2019-04-03 8:26 ` Dave Young
2019-04-03 16:14 ` Borislav Petkov
2019-04-04 1:02 ` Chao Fan
2019-04-03 9:28 ` Chao Fan
2019-04-03 7:21 ` Chao Fan
2019-04-03 8:09 ` Dave Young
2019-04-03 8:23 ` Chao Fan [this message]
2019-04-03 9:02 ` Chao Fan
2019-04-03 9:39 ` Chao Fan
2019-04-04 1:23 ` Junichi Nomura
2019-04-04 2:52 ` Dave Young
2019-04-04 3:00 ` bhe
2019-04-04 3:10 ` bhe
2019-04-04 3:22 ` Dave Young
2019-04-04 6:41 ` Dave Young
2019-04-04 7:20 ` Chao Fan
2019-04-04 7:41 ` Dave Young
2019-04-04 7:48 ` Chao Fan
2019-04-04 12:22 ` Borislav Petkov
2019-04-04 14:08 ` Dave Young
2019-04-03 8:18 ` Dave Young
2019-04-02 10:25 ` [PATCH v3] " Junichi Nomura
2019-04-04 7:32 ` Dave Young
2019-04-04 12:24 ` Borislav Petkov
2019-04-04 14:12 ` Dave Young
2019-04-04 14:41 ` Borislav Petkov
2019-04-05 1:36 ` Dave Young
2019-04-05 4:19 ` Junichi Nomura
2019-03-28 23:11 ` [PATCH v2] x86/boot: Use EFI setup data if provided bhe
2019-03-29 3:34 ` Junichi Nomura
2019-03-29 3:52 ` bhe
2019-03-29 5:16 ` Junichi Nomura
2019-03-25 7:27 ` [PATCH] " Baoquan He
2019-03-25 7:53 ` Borislav Petkov
2019-03-25 8:21 ` Baoquan He
2019-03-25 8:43 ` Thomas Gleixner
2019-03-25 9:03 ` Baoquan He
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