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[18.181.137.102]) by smtp.gmail.com with ESMTPSA id 17-20020a056a00071100b004f0f941d1e8sm14258564pfl.24.2022.02.28.19.36.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Feb 2022 19:36:45 -0800 (PST) Date: Tue, 1 Mar 2022 03:36:38 +0000 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: Vlastimil Babka Cc: David Rientjes , Christoph Lameter , Joonsoo Kim , Pekka Enberg , Roman Gushchin , Andrew Morton , linux-mm@kvack.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org, Oliver Glitta , Faiyaz Mohammed , Dmitry Vyukov , Eric Dumazet , Jarkko Sakkinen , Johannes Berg , Yury Norov , Arnd Bergmann , James Bottomley , Matteo Croce , Marco Elver , Andrey Konovalov , Imran Khan , Zqiang Subject: [PATCH v2] mm/slub: initialize stack depot in boot process Message-ID: MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" commit ba10d4b46655 ("mm/slub: use stackdepot to save stack trace in objects") initializes stack depot in cache creation if SLAB_STORE_USER flag is set. This can make kernel crash because a cache can be crashed in various contexts. For example if user sets slub_debug=3DU, kernel crashes because create_boot_cache() calls stack_depot_init(), which tries to allocate hash table using memblock_alloc() if slab is not available. But memblock is also not available at that time. This patch solves the problem by initializing stack depot early in boot process if SLAB_STORE_USER debug flag is set globally or the flag is set for at least one cache. [ elver@google.com: initialize stack depot depending on slub_debug parameter instead of allowing stack_depot_init() to be called during kmem_cache_init() for simplicity. ] [ vbabka@suse.cz: parse slub_debug parameter in setup_slub_debug() and initialize stack depot in stack_depot_early_init(). ] Link: https://lore.kernel.org/all/YhyeaP8lrzKgKm5A@ip-172-31-19-208.ap-nort= heast-1.compute.internal/ Fixes: ba10d4b46655 ("mm/slub: use stackdepot to save stack trace in object= s") Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reported-by: kernel test robot --- include/linux/slab.h | 6 ++++++ include/linux/stackdepot.h | 3 ++- mm/slub.c | 18 +++++++++++++++--- 3 files changed, 23 insertions(+), 4 deletions(-) diff --git a/include/linux/slab.h b/include/linux/slab.h index 37bde99b74af..062128e0db10 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -763,6 +763,12 @@ extern void kvfree_sensitive(const void *addr, size_t = len); unsigned int kmem_cache_size(struct kmem_cache *s); void __init kmem_cache_init_late(void); =20 +#if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_STACKDEPOT) +int slab_stack_depot_init(void); +#else +int slab_stack_depot_init(void) { return 0; } +#endif + #if defined(CONFIG_SMP) && defined(CONFIG_SLAB) int slab_prepare_cpu(unsigned int cpu); int slab_dead_cpu(unsigned int cpu); diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 17f992fe6355..a813a2673c48 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -12,6 +12,7 @@ #define _LINUX_STACKDEPOT_H =20 #include +#include =20 typedef u32 depot_stack_handle_t; =20 @@ -32,7 +33,7 @@ int stack_depot_init(void); #ifdef CONFIG_STACKDEPOT_ALWAYS_INIT static inline int stack_depot_early_init(void) { return stack_depot_init()= ; } #else -static inline int stack_depot_early_init(void) { return 0; } +static inline int stack_depot_early_init(void) { return slab_stack_depot_i= nit(); } #endif =20 depot_stack_handle_t stack_depot_save(unsigned long *entries, diff --git a/mm/slub.c b/mm/slub.c index a74afe59a403..2419fc3cc9f3 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -646,6 +646,14 @@ static slab_flags_t slub_debug; =20 static char *slub_debug_string; static int disable_higher_order_debug; +static bool init_stack_depot; + +int slab_stack_depot_init(void) +{ + if (init_stack_depot) + stack_depot_init(); + return 0; +} =20 /* * slub is about to manipulate internal object metadata. This memory lies @@ -1531,6 +1539,8 @@ static int __init setup_slub_debug(char *str) global_slub_debug_changed =3D true; } else { slab_list_specified =3D true; + if (flags & SLAB_STORE_USER) + init_stack_depot =3D true; } } =20 @@ -1546,6 +1556,10 @@ static int __init setup_slub_debug(char *str) global_flags =3D slub_debug; slub_debug_string =3D saved_str; } + + if (global_flags & SLAB_STORE_USER) + init_stack_depot =3D true; + out: slub_debug =3D global_flags; if (slub_debug !=3D 0 || slub_debug_string) @@ -1556,6 +1570,7 @@ static int __init setup_slub_debug(char *str) static_branch_unlikely(&init_on_free)) && (slub_debug & SLAB_POISON)) pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_al= loc/init_on_free\n"); + return 1; } =20 @@ -4221,9 +4236,6 @@ static int kmem_cache_open(struct kmem_cache *s, slab= _flags_t flags) s->remote_node_defrag_ratio =3D 1000; #endif =20 - 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 >=3D UP) { if (init_cache_random_seq(s)) --=20 2.33.1