From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CC9B03EBF3A for ; Tue, 27 Jan 2026 05:49:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769492975; cv=none; b=fOFU1ah6PldY6TaDHbKU9xBUtv+HBIAVLZcCi2DxmmbuJry+fFjXGcdMRr9Z1uwTf0ifcapP11j4Tv8TtkOONJwrsSbRKFSNUZh5Dv4O4RV83doGNjrwMAh56Rm6H/IiaQZ30Ld9UMXAc61I87C+by/2D29gXi2M9bLyn3hx3/w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769492975; c=relaxed/simple; bh=4jmOqRkRzXNaRPOHPT707dEMT6tJteeoRC1mPGdWnwY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=b28IRPLUpxIYXy1IAKsC1Ean7GPAc9hpuNPgpt6V1Rd0gmhKrknCiLms/jkG2J9m++qjeNxTuEErxfZZRuQu6qkPPVL/ivYnChmDBwbnMkz8yJPv2ZyxISJc4mwCwa51N+Gy1rTiYpTGPFo3EiOsNrzRx4WXrWBeFebf6OpYLaI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=eyvFbmSZ; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eyvFbmSZ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1769492972; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FQViPQ8jqp6BXqY59Q4PpPvPb9kmHYBuT9rtqSSpXIY=; b=eyvFbmSZ6M0h1BrNlb4b6H9o3GARILMqNevSa25ODz7IZCZwfwPFknOfyTMNc/4yZKd+3W 8FheATfX22Dd5gpmG4XYoeE+suaTDxHWUvHD6tPLNAAt0qGg10NyTuYR5/1LSP6sYe93hv CC0RcBefAeQMChk8RNHXQS6Ziqh0O94= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-333-1nXIXkb9MrapWWMYmwp28Q-1; Tue, 27 Jan 2026 00:49:29 -0500 X-MC-Unique: 1nXIXkb9MrapWWMYmwp28Q-1 X-Mimecast-MFC-AGG-ID: 1nXIXkb9MrapWWMYmwp28Q_1769492967 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6357019775A7; Tue, 27 Jan 2026 05:49:27 +0000 (UTC) Received: from localhost (unknown [10.72.112.123]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9614018004D8; Tue, 27 Jan 2026 05:49:25 +0000 (UTC) Date: Tue, 27 Jan 2026 13:49:20 +0800 From: Baoquan He To: Li Chen Cc: Andrew Morton , Eric Biggers , Steven Chen , Alexander Graf , Sourabh Jain , Philipp Rudo , "Steven Rostedt (Google)" , Ricardo Ribalda , Ross Zwisler , kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] kexec: derive purgatory entry from symbol Message-ID: References: <20260120124005.148381-1-me@linux.beauty> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260120124005.148381-1-me@linux.beauty> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Hi Li Chen, On 01/20/26 at 08:40pm, Li Chen wrote: > kexec_load_purgatory() derives image->start by locating e_entry inside an > SHF_EXECINSTR section. If the purgatory object contains multiple executable > sections with overlapping sh_addr, the entrypoint check can match more than > once and trigger a WARN. > > Derive the entry section from the purgatory_start symbol when present and > compute image->start from its final placement. Keep the existing e_entry > fallback for purgatories that do not expose the symbol. > > WARNING: kernel/kexec_file.c:1009 at kexec_load_purgatory+0x395/0x3c0, CPU#10: kexec/1784 > Call Trace: > > bzImage64_load+0x133/0xa00 > __do_sys_kexec_file_load+0x2b3/0x5c0 > do_syscall_64+0x81/0x610 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > Fixes: 8652d44f466a ("kexec: support purgatories with .text.hot sections") > Signed-off-by: Li Chen Thanks for fixing the issue. Could you tell how we can trigger this issue so that I can reproduce it? > --- > kernel/kexec_file.c | 24 ++++++++++++++++++++++-- > 1 file changed, 22 insertions(+), 2 deletions(-) > > diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c > index 3f1d6c4e8ff2..d3c68c6b4bbc 100644 > --- a/kernel/kexec_file.c > +++ b/kernel/kexec_file.c > @@ -880,6 +880,8 @@ static int kexec_calculate_store_digests(struct kimage *image) > } > > #ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY > +static const Elf_Sym * kexec_purgatory_find_symbol(struct purgatory_info *pi, > + const char *name); Here, is it better to move the whole function body of kexec_purgatory_find_symbol() here so that kexec_purgatory_setup_sechdrs() can see it too? Other than the concerns about how to reproducing and above one, this patch looks good to me. Thanks Baoquan > /* > * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory. > * @pi: Purgatory to be loaded. > @@ -958,6 +960,10 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, > unsigned long offset; > size_t sechdrs_size; > Elf_Shdr *sechdrs; > + const Elf_Sym *entry_sym; > + u16 entry_shndx = 0; > + unsigned long entry_off = 0; > + bool start_fixed = false; > int i; > > /* > @@ -975,6 +981,12 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, > bss_addr = kbuf->mem + kbuf->bufsz; > kbuf->image->start = pi->ehdr->e_entry; > > + entry_sym = kexec_purgatory_find_symbol(pi, "purgatory_start"); > + if (entry_sym) { > + entry_shndx = entry_sym->st_shndx; > + entry_off = entry_sym->st_value; > + } > + > for (i = 0; i < pi->ehdr->e_shnum; i++) { > unsigned long align; > void *src, *dst; > @@ -992,6 +1004,13 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, > > offset = ALIGN(offset, align); > > + if (!start_fixed && entry_sym && i == entry_shndx && > + (sechdrs[i].sh_flags & SHF_EXECINSTR) && > + entry_off < sechdrs[i].sh_size) { > + kbuf->image->start = kbuf->mem + offset + entry_off; > + start_fixed = true; > + } > + > /* > * Check if the segment contains the entry point, if so, > * calculate the value of image->start based on it. > @@ -1002,13 +1021,14 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, > * is not set to the initial value, and warn the user so they > * have a chance to fix their purgatory's linker script. > */ > - if (sechdrs[i].sh_flags & SHF_EXECINSTR && > + if (!start_fixed && sechdrs[i].sh_flags & SHF_EXECINSTR && > pi->ehdr->e_entry >= sechdrs[i].sh_addr && > pi->ehdr->e_entry < (sechdrs[i].sh_addr > + sechdrs[i].sh_size) && > - !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) { > + kbuf->image->start == pi->ehdr->e_entry) { > kbuf->image->start -= sechdrs[i].sh_addr; > kbuf->image->start += kbuf->mem + offset; > + start_fixed = true; > } > > src = (void *)pi->ehdr + sechdrs[i].sh_offset; > -- > 2.52.0 > >