From: Christoph Lameter <cl@gentwo.de>
To: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Roman Gushchin <roman.gushchin@linux.dev>,
Joe Perches <joe@perches.com>,
Vasily Averin <vasily.averin@linux.dev>,
Matthew WilCox <willy@infradead.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Marco Elver <elver@google.com>
Subject: Re: [PATCH 16/16] mm/sl[au]b: check if large object is valid in __ksize()
Date: Wed, 13 Jul 2022 12:07:39 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.22.394.2207131205590.112646@gentwo.de> (raw)
In-Reply-To: <Ys6Pp6ZPwJTdJvpk@ip-172-31-24-42.ap-northeast-1.compute.internal>
On Wed, 13 Jul 2022, Hyeonggon Yoo wrote:
> > Why return 0 if there is an error and why bother the callers with these
> > checks. BUG()?
>
> I thought BUG should be used when there is no other solution.
Spurios returns of 0 that the caller has to check for is a solution?
> > I guess this is an error since the order-0 page cannot come from slab
> > allocations.
>
> comment in ksize() says:
> "The caller must guarantee that objp points to a valid object
> previously allocated with either kmalloc() or kmem_cache_alloc()."
>
> It should not be used on order-0 page that is not allocated from slab. No?
I guess we would need to check. Code could exist that does this.
Getting a 0 size would be surprising too here. BUG()? Or WARN() and return
PAGE_SIZE.
next prev parent reply other threads:[~2022-07-13 10:07 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-12 13:39 [PATCH v3 00/15] common kmalloc v3 Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 1/15] mm/slab: move NUMA-related code to __do_cache_alloc() Hyeonggon Yoo
2022-07-12 14:29 ` Christoph Lameter
2022-07-13 9:39 ` Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 2/15] mm/slab: cleanup slab_alloc() and slab_alloc_node() Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 03/15] mm/slab_common: remove CONFIG_NUMA ifdefs for common kmalloc functions Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 04/15] mm/slab_common: cleanup kmalloc_track_caller() Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 05/15] mm/sl[au]b: factor out __do_kmalloc_node() Hyeonggon Yoo
2022-07-28 14:45 ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH v3 06/15] mm/slab_common: fold kmalloc_order_trace() into kmalloc_large() Hyeonggon Yoo
2022-07-28 15:23 ` Vlastimil Babka
2022-08-01 13:26 ` Hyeonggon Yoo
2022-08-01 13:36 ` Vlastimil Babka
2022-08-02 2:54 ` Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 07/15] mm/slub: move kmalloc_large_node() to slab_common.c Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 08/15] mm/slab_common: kmalloc_node: pass large requests to page allocator Hyeonggon Yoo
2022-07-28 16:09 ` Vlastimil Babka
2022-08-01 14:37 ` Hyeonggon Yoo
2022-08-01 14:44 ` Vlastimil Babka
2022-08-02 8:59 ` Hyeonggon Yoo
2022-08-02 9:32 ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH v3 09/15] mm/slab_common: cleanup kmalloc_large() Hyeonggon Yoo
2022-07-28 16:13 ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH v3 10/15] mm/slab: kmalloc: pass requests larger than order-1 page to page allocator Hyeonggon Yoo
2022-07-28 16:25 ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH v3 11/15] mm/sl[au]b: introduce common alloc/free functions without tracepoint Hyeonggon Yoo
2022-07-29 9:49 ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH v3 12/15] mm/sl[au]b: generalize kmalloc subsystem Hyeonggon Yoo
2022-07-29 10:25 ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH v3 13/15] mm/slab_common: unify NUMA and UMA version of tracepoints Hyeonggon Yoo
2022-07-29 10:52 ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH 14/16] mm/slab_common: drop kmem_alloc & avoid dereferencing fields when not using Hyeonggon Yoo
2022-07-29 11:23 ` Vlastimil Babka
2022-08-02 9:22 ` Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH 15/16] mm/slab_common: move definition of __ksize() to mm/slab.h Hyeonggon Yoo
2022-07-29 11:47 ` Vlastimil Babka
2022-08-02 9:25 ` Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH 16/16] mm/sl[au]b: check if large object is valid in __ksize() Hyeonggon Yoo
2022-07-12 15:13 ` Christoph Lameter
2022-07-13 9:25 ` Hyeonggon Yoo
2022-07-13 10:07 ` Christoph Lameter [this message]
2022-07-13 10:33 ` Marco Elver
2022-07-14 9:15 ` Christoph Lameter
2022-07-14 10:30 ` Marco Elver
2022-07-20 10:05 ` Hyeonggon Yoo
2022-07-29 11:50 ` Vlastimil Babka
2022-07-29 15:08 ` [PATCH v3 00/15] common kmalloc v3 Vlastimil Babka
2022-08-14 10:06 ` Hyeonggon Yoo
2022-08-15 12:59 ` Vlastimil Babka
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