All of lore.kernel.org
 help / color / mirror / Atom feed
From: Mike Rapoport <rppt@kernel.org>
To: gaohan@iscas.ac.cn
Cc: Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Baoquan He <baoquan.he@linux.dev>,
	Pasha Tatashin <pasha.tatashin@soleen.com>,
	Pratyush Yadav <pratyush@kernel.org>, Yao Zi <me@ziyao.cc>,
	Han Gao <rabenda.cn@gmail.com>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev, kexec@lists.infradead.org
Subject: Re: [PATCH 4/5] kexec_core: Clear the unused part of CMA segments
Date: Tue, 3 Nov 2026 12:15:16 +0200	[thread overview]
Message-ID: <aum0NFfSezGOiR0K@kernel.org> (raw)
In-Reply-To: <20261023-riscv-kexec-cma-fixes-v1-4-825b90ea23c4@iscas.ac.cn>

On Fri, Oct 23, 2026 at 03:33:17PM +0800, Han Gao via B4 Relay wrote:
> From: Han Gao <gaohan@iscas.ac.cn>
> 
> kimage_load_cma_segment() copies the source data into pages that are not
> cleared, but zeroes nothing after it: the final memset() runs once the
> loop has consumed all of memsz. The tail of the last source page and
> every page beyond bufsz keep stale data, while the purgatory digest
> covers them as zeroes.
> 
> A kexec_file reboot then stops in purgatory on a digest mismatch, for
> instance when the DTB lands in a reused CMA page.
> 
> Zero the remainder of each page instead.
> 
> Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
> Signed-off-by: Han Gao <gaohan@iscas.ac.cn>

Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
>  kernel/kexec_core.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index dc770b9a6d05..0d6e10bea4e4 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -780,15 +780,15 @@ static int kimage_load_cma_segment(struct kimage *image, int idx)
>  			goto out;
>  		}
>  
> +		/* CMA pages are not cleared: zero the part without source data */
> +		memset(ptr + uchunk, 0, mchunk - uchunk);
> +
>  		ptr    += mchunk;
>  		mbytes -= mchunk;
>  
>  		cond_resched();
>  	}
>  
> -	/* Clear any remainder */
> -	memset(ptr, 0, mbytes);
> -
>  out:
>  	return result;
>  }
> 
> -- 
> 2.55.0
> 
> 

-- 
Sincerely yours,
Mike.

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Mike Rapoport <rppt@kernel.org>
To: gaohan@iscas.ac.cn
Cc: Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Baoquan He <baoquan.he@linux.dev>,
	Pasha Tatashin <pasha.tatashin@soleen.com>,
	Pratyush Yadav <pratyush@kernel.org>, Yao Zi <me@ziyao.cc>,
	Han Gao <rabenda.cn@gmail.com>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev, kexec@lists.infradead.org
Subject: Re: [PATCH 4/5] kexec_core: Clear the unused part of CMA segments
Date: Tue, 3 Nov 2026 12:15:16 +0200	[thread overview]
Message-ID: <aum0NFfSezGOiR0K@kernel.org> (raw)
In-Reply-To: <20261023-riscv-kexec-cma-fixes-v1-4-825b90ea23c4@iscas.ac.cn>

On Fri, Oct 23, 2026 at 03:33:17PM +0800, Han Gao via B4 Relay wrote:
> From: Han Gao <gaohan@iscas.ac.cn>
> 
> kimage_load_cma_segment() copies the source data into pages that are not
> cleared, but zeroes nothing after it: the final memset() runs once the
> loop has consumed all of memsz. The tail of the last source page and
> every page beyond bufsz keep stale data, while the purgatory digest
> covers them as zeroes.
> 
> A kexec_file reboot then stops in purgatory on a digest mismatch, for
> instance when the DTB lands in a reused CMA page.
> 
> Zero the remainder of each page instead.
> 
> Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
> Signed-off-by: Han Gao <gaohan@iscas.ac.cn>

Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

> ---
>  kernel/kexec_core.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index dc770b9a6d05..0d6e10bea4e4 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -780,15 +780,15 @@ static int kimage_load_cma_segment(struct kimage *image, int idx)
>  			goto out;
>  		}
>  
> +		/* CMA pages are not cleared: zero the part without source data */
> +		memset(ptr + uchunk, 0, mchunk - uchunk);
> +
>  		ptr    += mchunk;
>  		mbytes -= mchunk;
>  
>  		cond_resched();
>  	}
>  
> -	/* Clear any remainder */
> -	memset(ptr, 0, mbytes);
> -
>  out:
>  	return result;
>  }
> 
> -- 
> 2.55.0
> 
> 

-- 
Sincerely yours,
Mike.


  parent reply	other threads:[~2026-11-03 10:15 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-23  7:33 [PATCH 0/5] riscv: kexec: fix kexec_file with CMA-backed segments Han Gao via B4 Relay
2026-10-23  7:33 ` Han Gao via B4 Relay
2026-10-23  7:33 ` Han Gao
2026-10-23  7:33 ` [PATCH 1/5] riscv: kexec: Disable the MMU before walking the entry list Han Gao via B4 Relay
2026-10-23  7:33   ` Han Gao via B4 Relay
2026-10-23  7:33   ` Han Gao
2026-10-23  7:39   ` sashiko-bot
2026-10-23  7:33 ` [PATCH 2/5] riscv: kexec_file: Pair PC-relative low parts with their high parts Han Gao via B4 Relay
2026-10-23  7:33   ` Han Gao via B4 Relay
2026-10-23  7:33   ` Han Gao
2026-10-23  7:45   ` sashiko-bot
2026-10-23  7:33 ` [PATCH 3/5] kexec_file: Honor the segment alignment for CMA allocations Han Gao via B4 Relay
2026-10-23  7:33   ` Han Gao via B4 Relay
2026-10-23  7:33   ` Han Gao
2026-10-23  8:18   ` sashiko-bot
2026-11-03 10:14   ` Mike Rapoport
2026-11-03 10:14     ` Mike Rapoport
2026-10-23  7:33 ` [PATCH 4/5] kexec_core: Clear the unused part of CMA segments Han Gao via B4 Relay
2026-10-23  7:33   ` Han Gao via B4 Relay
2026-10-23  7:33   ` Han Gao
2026-10-23  8:04   ` sashiko-bot
2026-11-03 10:15   ` Mike Rapoport [this message]
2026-11-03 10:15     ` Mike Rapoport
2026-10-23  7:33 ` [PATCH 5/5] riscv: mm: Reserve the DTB before scanning reserved memory Han Gao via B4 Relay
2026-10-23  7:33   ` Han Gao via B4 Relay
2026-10-23  7:33   ` Han Gao
2026-10-23  8:06   ` sashiko-bot

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=aum0NFfSezGOiR0K@kernel.org \
    --to=rppt@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=alex@ghiti.fr \
    --cc=aou@eecs.berkeley.edu \
    --cc=baoquan.he@linux.dev \
    --cc=gaohan@iscas.ac.cn \
    --cc=justinstitt@google.com \
    --cc=kexec@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=llvm@lists.linux.dev \
    --cc=me@ziyao.cc \
    --cc=morbo@google.com \
    --cc=nathan@kernel.org \
    --cc=ndesaulniers@google.com \
    --cc=palmer@dabbelt.com \
    --cc=pasha.tatashin@soleen.com \
    --cc=pjw@kernel.org \
    --cc=pratyush@kernel.org \
    --cc=rabenda.cn@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.