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Message-ID: <Yh8szz+UxqddwK7j@linux.ibm.com> Date: Wed, 2 Mar 2022 10:37:35 +0200 From: Mike Rapoport <rppt@...ux.ibm.com> To: Hyeonggon Yoo <42.hyeyoo@...il.com> Cc: Vlastimil Babka <vbabka@...e.cz>, David Rientjes <rientjes@...gle.com>, Christoph Lameter <cl@...ux.com>, Joonsoo Kim <iamjoonsoo.kim@....com>, Pekka Enberg <penberg@...nel.org>, Roman Gushchin <roman.gushchin@...ux.dev>, Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org, patches@...ts.linux.dev, linux-kernel@...r.kernel.org, Oliver Glitta <glittao@...il.com>, Faiyaz Mohammed <faiyazm@...eaurora.org>, Jonathan Corbet <corbet@....net>, Randy Dunlap <rdunlap@...radead.org>, Marco Elver <elver@...gle.com>, Karolina Drobnik <karolinadrobnik@...il.com> Subject: Re: [PATCH 0/5] SLUB debugfs improvements based on stackdepot On Mon, Feb 28, 2022 at 09:27:02PM +0000, Hyeonggon Yoo wrote: > On Mon, Feb 28, 2022 at 08:10:18PM +0100, Vlastimil Babka wrote: > > On 2/26/22 08:19, Hyeonggon Yoo wrote: > > > On Fri, Feb 25, 2022 at 07:03:13PM +0100, Vlastimil Babka wrote: > > >> Hi, > > >> > > >> this series combines and revives patches from Oliver's last year > > >> bachelor thesis (where I was the advisor) that make SLUB's debugfs > > >> files alloc_traces and free_traces more useful. > > >> The resubmission was blocked on stackdepot changes that are now merged, > > >> as explained in patch 2. > > >> > > > > > > Hello. I just started review/testing this series. > > > > > > it crashed on my system (arm64) > > > > Hmm, interesting. On x86_64 this works for me and stackdepot is allocated > > from memblock. arm64 must have memblock freeing happen earlier or something. > > (CCing memblock experts) > > > > > I ran with boot parameter slub_debug=U, and without KASAN. > > > So CONFIG_STACKDEPOT_ALWAYS_INIT=n. > > > > > > void * __init memblock_alloc_try_nid( > > > phys_addr_t size, phys_addr_t align, > > > 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_); > > > ptr = memblock_alloc_internal(size, align, > > > min_addr, max_addr, nid, false); > > > if (ptr) > > > memset(ptr, 0, size); <--- Crash Here > > > > > > return ptr; > > > } > > > > > > It crashed during create_boot_cache() -> stack_depot_init() -> > > > memblock_alloc(). > > > > > > I think That's because, in kmem_cache_init(), both slab and memblock is not > > > available. (AFAIU memblock is not available after mem_init() because of > > > memblock_free_all(), right?) > > > > Hm yes I see, even in x86_64 version mem_init() calls memblock_free_all(). > > But then, I would expect stack_depot_init() to detect that memblock_alloc() > > returns NULL, we print ""Stack Depot hash table allocation failed, > > disabling" and disable it. Instead it seems memblock_alloc() returns > > something that's already potentially used by somebody else? Sounds like a bug? > > > By the way, I fixed this by allowing stack_depot_init() to be called in > kmem_cache_init() too [1] and Marco suggested that calling > stack_depot_init() depending on slub_debug parameter for simplicity. [2] > > I would prefer [2], Would you take a look? > > [1] https://lkml.org/lkml/2022/2/27/31 > > [2] https://lkml.org/lkml/2022/2/28/717 I have the third version :) diff --git a/mm/slub.c b/mm/slub.c index a74afe59a403..0c3ab2335b46 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1548,6 +1548,10 @@ static int __init setup_slub_debug(char *str) } out: slub_debug = global_flags; + + if (slub_flags & SLAB_STORE_USER && IS_ENABLED(CONFIG_STACKDEPOT)) + stack_depot_early_init(); + if (slub_debug != 0 || slub_debug_string) static_branch_enable(&slub_debug_enabled); else @@ -4221,9 +4225,6 @@ static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags) s->remote_node_defrag_ratio = 1000; #endif - if (s->flags & SLAB_STORE_USER && IS_ENABLED(CONFIG_STACKDEPOT)) - stack_depot_init(); - /* Initialize the pre-computed randomized freelist if slab is up */ if (slab_state >= UP) { if (init_cache_random_seq(s)) > -- > Thank you, You are awesome! > Hyeonggon :-) -- Sincerely yours, Mike.
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