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From: Nick Terrell <terrelln@fb.com>
To: Feng Tang <feng.tang@intel.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	X86 ML <x86@kernel.org>, Sedat Dilek <sedat.dilek@gmail.com>,
	Ingo Molnar <mingo@kernel.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	"linux-kbuild@vger.kernel.org" <linux-kbuild@vger.kernel.org>,
	"rong.a.chen@intel.com" <rong.a.chen@intel.com>,
	"philip.li@intel.com" <philip.li@intel.com>
Subject: Re: PROBLEM: zstd bzImage decompression fails for some x86_32 config on 5.9-rc1
Date: Mon, 28 Sep 2020 18:02:03 +0000	[thread overview]
Message-ID: <74757C2A-7C09-4C2E-9828-E8D12EE4706B@fb.com> (raw)
In-Reply-To: <20200928085505.GA22244@shbuild999.sh.intel.com>



> On Sep 28, 2020, at 1:55 AM, Feng Tang <feng.tang@intel.com> wrote:
> 
> Hi Nick,
> 
> 0day has found some kernel decomprssion failure case since 5.9-rc1 (X86_32
> build), and it could be related with ZSTD code, though initially we bisected
> to some other commits.
> 
> The error messages are: 
> 	
> 	early console in setup code
> 	Wrong EFI loader signature.
> 	early console in extract_kernel
> 	input_data: 0x046f50b4
> 	input_len: 0x01ebbeb6
> 	output: 0x01000000
> 	output_len: 0x04fc535c
> 	kernel_total_size: 0x055f5000
> 	needed_size: 0x055f5000
> 	
> 	Decompressing Linux...
> 	
> 	ZSTD-compressed data is corrupt
> 
> This could be reproduced by compiling the kernel with attached config,
> and use QEMU to boot it.
> 
> We suspect it could be related with the kernel size, as we only see
> it on big kernel, and some more info are:
> 
> * If we remove a lot of kernel config to build a much smaller kernel,
>  it will boot fine
> 
> * If we change the zstd algorithm from zstd22 to zstd19, the kernel will
>  boot fine with below patch
> 
> 	diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
> 	index 3962f59..8fe71ba 100644
> 	--- a/arch/x86/boot/compressed/Makefile
> 	+++ b/arch/x86/boot/compressed/Makefile
> 	@@ -147,7 +147,7 @@ $(obj)/vmlinux.bin.lzo: $(vmlinux.bin.all-y) FORCE
> 	 $(obj)/vmlinux.bin.zst: $(vmlinux.bin.all-y) FORCE
> 	-	$(call if_changed,zstd22)
> 	+	$(call if_changed,zstd)
> 
> 
> Please let me know if you need more info, and sorry for the late report
> as we just tracked down to this point.

Thanks for the report, I will look into it today.

Best,
Nick

> Thanks,
> Feng
> 
> 
> 
> <zstd_x86_32.config>


  parent reply	other threads:[~2020-09-28 18:02 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200928085505.GA22244@shbuild999.sh.intel.com>
2020-09-28  9:53 ` PROBLEM: zstd bzImage decompression fails for some x86_32 config on 5.9-rc1 Sedat Dilek
2020-09-28 18:02 ` Nick Terrell [this message]
2020-09-29  5:15   ` Nick Terrell
2020-09-29  5:47     ` Feng Tang
2020-10-03 18:49       ` Sedat Dilek

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