linux-kernel - Re: [PATCH 4/4] memblock: stop poisoning raw allocations

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Message-ID: <72be13936ca341897d2fd7c65fb4345a8467c571.camel@perches.com>
Date:   Sat, 31 Jul 2021 10:13:04 -0700
From:   Joe Perches <joe@...ches.com>
To:     Mike Rapoport <rppt@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     Michal Simek <monstr@...str.eu>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH 4/4] memblock: stop poisoning raw allocations

On Wed, 2021-07-14 at 15:37 +0300, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@...ux.ibm.com>
> 
> Functions memblock_alloc_exact_nid_raw() and memblock_alloc_try_nid_raw()
> are intended for early memory allocation without overhead of zeroing the
> allocated memory. Since these functions were used to allocate the memory
> map, they have ended up with addition of a call to page_init_poison() that
> poisoned the allocated memory when CONFIG_PAGE_POISON was set.
> 
> Since the memory map is allocated using a dedicated memmep_alloc() function
> that takes care of the poisoning, remove page poisoning from the
> memblock_alloc_*_raw() functions.
[]
> diff --git a/mm/memblock.c b/mm/memblock.c
[]
> @@ -1490,18 +1490,12 @@ void * __init memblock_alloc_exact_nid_raw(
>  			phys_addr_t min_addr, phys_addr_t max_addr,
>  			int nid)
>  {
> -	void *ptr;
> -
>  	memblock_dbg("%s: %llu bytes align=0x%llx nid=%d from=%pa max_addr=%pa %pS\n",
>  		     __func__, (u64)size, (u64)align, nid, &min_addr,
>  		     &max_addr, (void *)_RET_IP_);

unassociated trivia:

casting _RET_IP_ back to void * seems odd as the define is
include/linux/kernel.h:#define _RET_IP_         (unsigned long)__builtin_return_address(0)

It's probably easier to understand as just __builtin_return_address(0)

> @@ -1528,18 +1522,12 @@ void * __init memblock_alloc_try_nid_raw(
>  			phys_addr_t min_addr, phys_addr_t max_addr,
>  			int nid)
>  {
> -	void *ptr;
> -
>  	memblock_dbg("%s: %llu bytes align=0x%llx nid=%d from=%pa max_addr=%pa %pS\n",
>  		     __func__, (u64)size, (u64)align, nid, &min_addr,
>  		     &max_addr, (void *)_RET_IP_);

here too