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From: Song Liu <songliubraving@fb.com>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: Song Liu <song@kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"hch@lst.de" <hch@lst.de>, Kernel Team <Kernel-team@fb.com>,
	"rick.p.edgecombe@intel.com" <rick.p.edgecombe@intel.com>,
	"dave.hansen@intel.com" <dave.hansen@intel.com>
Subject: Re: [RFC 3/5] modules, x86: use vmalloc_exec for module core
Date: Fri, 7 Oct 2022 06:46:49 +0000	[thread overview]
Message-ID: <2063847A-42D6-4A26-992F-0DD32A5E1F05@fb.com> (raw)
In-Reply-To: <Yz9m9N9qG2OOdyPy@bombadil.infradead.org>



> On Oct 6, 2022, at 4:38 PM, Luis Chamberlain <mcgrof@kernel.org> wrote:
> 
> On Thu, Aug 18, 2022 at 03:42:16PM -0700, Song Liu wrote:
>> diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
>> index 100446ffdc1d..570af623e28f 100644
>> --- a/arch/x86/kernel/module.c
>> +++ b/arch/x86/kernel/module.c
>> @@ -229,6 +229,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
>> 	bool early = me->state == MODULE_STATE_UNFORMED;
>> 	void *(*write)(void *, const void *, size_t) = memcpy;
>> 
>> +	early = false;
>> 	if (!early) {
>> 		write = text_poke;
>> 		mutex_lock(&text_mutex);
> 
> As per 88fc078a7a8f6 ("x86/module: Use text_poke() for late
> relocations") I'm curious why we have to take the live patching
> path now all the time?

Since vmalloc_exec returns read-only memory, we need text_poke()
for any operation to it. 

Does this answer your question?

Song


  reply	other threads:[~2022-10-07  6:47 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-18 22:42 [RFC 0/5] vmalloc_exec for modules and BPF programs Song Liu
2022-08-18 22:42 ` [RFC 1/5] vmalloc: introduce vmalloc_exec and vfree_exec Song Liu
2022-10-06 23:15   ` Luis Chamberlain
2022-10-07  6:39     ` Song Liu
2022-08-18 22:42 ` [RFC 2/5] bpf: use vmalloc_exec Song Liu
2022-08-18 22:42 ` [RFC 3/5] modules, x86: use vmalloc_exec for module core Song Liu
2022-10-06 23:38   ` Luis Chamberlain
2022-10-07  6:46     ` Song Liu [this message]
2022-08-18 22:42 ` [RFC 4/5] vmalloc_exec: share a huge page with kernel text Song Liu
2022-10-06 23:44   ` Luis Chamberlain
2022-10-07  6:53     ` Song Liu
2022-08-18 22:42 ` [RFC 5/5] vmalloc: vfree_exec: free unused vm_struct Song Liu
2022-08-22 15:46 ` [RFC 0/5] vmalloc_exec for modules and BPF programs Song Liu
2022-08-22 16:34   ` Peter Zijlstra
2022-08-22 16:56     ` Song Liu
2022-08-23  5:42       ` Peter Zijlstra
2022-08-23  6:39         ` Christophe Leroy
2022-08-23  6:57           ` Song Liu
2022-08-23  6:55         ` Song Liu
2022-08-24 17:06       ` Song Liu

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