From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D8AA5D6C287 for ; Tue, 19 Nov 2024 19:37:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6EEB26B0089; Tue, 19 Nov 2024 14:37:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 676F46B008A; Tue, 19 Nov 2024 14:37:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 518C76B008C; Tue, 19 Nov 2024 14:37:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 340CB6B0089 for ; Tue, 19 Nov 2024 14:37:12 -0500 (EST) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id D5A041207A4 for ; Tue, 19 Nov 2024 19:37:11 +0000 (UTC) X-FDA: 82803851550.23.D1AA190 Received: from mail-wm1-f50.google.com (mail-wm1-f50.google.com [209.85.128.50]) by imf09.hostedemail.com (Postfix) with ESMTP id EB78214000A for ; Tue, 19 Nov 2024 19:36:34 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=LcV+wK60; spf=pass (imf09.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.128.50 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1732044785; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=GdOKblGV+cU/H2wS4BCTlQ23goHv8tshPrwSMll3Yd8=; b=aS9YMKff2g9oxnXM/ciYrE+qt4TLpLg91xhnYCPdp20ef0md/A10HaswxUCLCTco2Cg9lf p7VHjWsHXectF5a/huAA+xFd29QJIcCLWocGaSr5GGCn0FbaJmr6qAHL+8nQjNJGU9B8LQ ESdiij+W3/Kpb1s282o/k1z5IMDk8fE= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=LcV+wK60; spf=pass (imf09.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.128.50 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1732044785; a=rsa-sha256; cv=none; b=Pq+ju+xrAPxvbZKFmLCdSniTDGsJ7rf5lcW5ufSgLH5bP/lzqefk9yH+Qs0hGYG4tZIWj1 +BOu+15MldsZOKDgxshYsWQIj8HPXWQYJj1j3AuyhSmM8j4X4jyiZT1GcWYX0B4uC82fw0 EfdxqUtL4qEuoZplq6/S2kYkL7F7DOM= Received: by mail-wm1-f50.google.com with SMTP id 5b1f17b1804b1-4315839a7c9so12241495e9.3 for ; Tue, 19 Nov 2024 11:37:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1732045028; x=1732649828; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=GdOKblGV+cU/H2wS4BCTlQ23goHv8tshPrwSMll3Yd8=; b=LcV+wK60h1jnVVBF3mZeqHMVXPZGpoMgIFUfRmYd2RZk5z1Hg8NF2nyyHkh/oUDkeW ZQHDM8OI4BiDVsbLKARqFWRR9I1Wm/vowHRJXz/Cy1g7wSHjAsXajEXgVgyH6xEj5jo4 H3JcjsZp186sYniYI4w0NSXjf7NpeCa4hhkTatGwez3/mqh3xSHiEVf65yaEKhZo7aBC PS6O/sI/E2n2XbkSMdjcEX3Beql3bx/zWcWsFJZ7qzaqkp24XCcAIgz4m7RYG4wtDN+A /7AuF3HO41KGvC/3LG9XOiTWK2QsbmAKnOnFebbYNafqVpZWLc3OaqkOOg7Ciu81eyvX 0T5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1732045028; x=1732649828; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=GdOKblGV+cU/H2wS4BCTlQ23goHv8tshPrwSMll3Yd8=; b=MPehm5TBLfIQD8JJa0rSyBQNdwtMgUmGEXQulwyhOA3A04fh3M5HbpdCkZ8bZ11Ma0 J4ciNwqUK3WFG6D4TCqbaSKYX6uC7cWe/Stb10al60LZFiNp/YRDgGSZ6knhE34SHLnq s40W5KFW/2WJbD/sqjsSK6cBp0BW3oeo5HUjDMaQoTEfhLFq5XqZcpWaJ1Fjc1HJ/8Lt Yc+g6OD69E7ZQLfygYeeOYubd2hCh5zAiaOvRg9bwC0FC1ZT/JYdzaewQEhsySXWYsLW CwYy694YsUJ320y7PSCvIy37WRXfykNGTRVibzvcBWeab05cQfycM5iL2yb9Qshi/hqj ws9w== X-Forwarded-Encrypted: i=1; AJvYcCVMacfukDkgaevyExEM84uAW/xxg9p5/qp7V+mt94FIfoU+4SxAZliCuPN9J2VDClFLin28jMTlqg==@kvack.org X-Gm-Message-State: AOJu0YyORTntcM1vNN1hitJl6mtX0fIinF9JBME0xqnQNsRIpmmBUSL5 ZhVfJ8OXgPoS6YNVk7iC2rmTiNdVjEXW01tIh87NjuX44H5SQuHWlqtx5VGXxYHn9F17/gkcGhH ITLHOOBaDtT/PFilS2ed/I9mBOts= X-Google-Smtp-Source: AGHT+IH+0xv4nxzUSBUEH+sZf0d14xb3n4S11il50ZDggLNrmj8liu/Jm0Y4Op8GtAnsbxou5fmbbQuPuIYIRrdK9ok= X-Received: by 2002:a05:6000:2805:b0:382:2ba9:9d65 with SMTP id ffacd0b85a97d-38254afb065mr13810f8f.31.1732045028095; Tue, 19 Nov 2024 11:37:08 -0800 (PST) MIME-Version: 1.0 References: <67275485.050a0220.3c8d68.0a37.GAE@google.com> <20241104114506.GC24862@noisy.programming.kicks-ass.net> <20241119155701.GYennzPF@linutronix.de> In-Reply-To: <20241119155701.GYennzPF@linutronix.de> From: Andrey Konovalov Date: Tue, 19 Nov 2024 20:36:56 +0100 Message-ID: Subject: Re: [PATCH] kasan: Remove kasan_record_aux_stack_noalloc(). To: Sebastian Andrzej Siewior Cc: Marco Elver , Peter Zijlstra , Vlastimil Babka , syzbot , Liam.Howlett@oracle.com, akpm@linux-foundation.org, jannh@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lorenzo.stoakes@oracle.com, syzkaller-bugs@googlegroups.com, kasan-dev , Andrey Ryabinin , Alexander Potapenko , Waiman Long , dvyukov@google.com, vincenzo.frascino@arm.com, paulmck@kernel.org, frederic@kernel.org, neeraj.upadhyay@kernel.org, joel@joelfernandes.org, josh@joshtriplett.org, boqun.feng@gmail.com, urezki@gmail.com, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang1211@gmail.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, tj@kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, Thomas Gleixner , roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, rcu@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: EB78214000A X-Stat-Signature: ggumaxodekwoyc1mys9bf4mtr1xr57ub X-Rspam-User: X-HE-Tag: 1732044994-887746 X-HE-Meta: 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 k+aS7G7y 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Nov 19, 2024 at 4:57=E2=80=AFPM Sebastian Andrzej Siewior wrote: > > From: Peter Zijlstra > > kasan_record_aux_stack_noalloc() was introduced to record a stack trace > without allocating memory in the process. It has been added to callers > which were invoked while a raw_spinlock_t was held. > More and more callers were identified and changed over time. Is it a > good thing to have this while functions try their best to do a > locklessly setup? The only downside of having kasan_record_aux_stack() > not allocate any memory is that we end up without a stacktrace if > stackdepot runs out of memory and at the same stacktrace was not > recorded before. Marco Elver said in > https://lore.kernel.org/all/20210913112609.2651084-1-elver@google= .com/ > that this is rare. > > Make the kasan_record_aux_stack_noalloc() behaviour default as > kasan_record_aux_stack(). > > [bigeasy: Dressed the diff as patch. ] > > Reported-by: syzbot+39f85d612b7c20d8db48@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/all/67275485.050a0220.3c8d68.0a37.GAE@goo= gle.com > Signed-off-by: Peter Zijlstra (Intel) > Signed-off-by: Sebastian Andrzej Siewior > --- > > Didn't add a Fixes tag, didn't want to put > 7cb3007ce2da2 ("kasan: generic: introduce kasan_record_aux_stack_noall= oc()") > > there. > > include/linux/kasan.h | 2 -- > include/linux/task_work.h | 3 --- > kernel/irq_work.c | 2 +- > kernel/rcu/tiny.c | 2 +- > kernel/rcu/tree.c | 4 ++-- > kernel/sched/core.c | 2 +- > kernel/task_work.c | 14 +------------- > kernel/workqueue.c | 2 +- > mm/kasan/generic.c | 14 ++------------ > mm/slub.c | 2 +- > 10 files changed, 10 insertions(+), 37 deletions(-) > > diff --git a/include/linux/kasan.h b/include/linux/kasan.h > index 00a3bf7c0d8f0..1a623818e8b39 100644 > --- a/include/linux/kasan.h > +++ b/include/linux/kasan.h > @@ -488,7 +488,6 @@ void kasan_cache_create(struct kmem_cache *cache, uns= igned int *size, > void kasan_cache_shrink(struct kmem_cache *cache); > void kasan_cache_shutdown(struct kmem_cache *cache); > void kasan_record_aux_stack(void *ptr); > -void kasan_record_aux_stack_noalloc(void *ptr); > > #else /* CONFIG_KASAN_GENERIC */ > > @@ -506,7 +505,6 @@ static inline void kasan_cache_create(struct kmem_cac= he *cache, > static inline void kasan_cache_shrink(struct kmem_cache *cache) {} > static inline void kasan_cache_shutdown(struct kmem_cache *cache) {} > static inline void kasan_record_aux_stack(void *ptr) {} > -static inline void kasan_record_aux_stack_noalloc(void *ptr) {} > > #endif /* CONFIG_KASAN_GENERIC */ > > diff --git a/include/linux/task_work.h b/include/linux/task_work.h > index 2964171856e00..0646804860ff1 100644 > --- a/include/linux/task_work.h > +++ b/include/linux/task_work.h > @@ -19,9 +19,6 @@ enum task_work_notify_mode { > TWA_SIGNAL, > TWA_SIGNAL_NO_IPI, > TWA_NMI_CURRENT, > - > - TWA_FLAGS =3D 0xff00, > - TWAF_NO_ALLOC =3D 0x0100, > }; > > static inline bool task_work_pending(struct task_struct *task) > diff --git a/kernel/irq_work.c b/kernel/irq_work.c > index 2f4fb336dda17..73f7e1fd4ab4d 100644 > --- a/kernel/irq_work.c > +++ b/kernel/irq_work.c > @@ -147,7 +147,7 @@ bool irq_work_queue_on(struct irq_work *work, int cpu= ) > if (!irq_work_claim(work)) > return false; > > - kasan_record_aux_stack_noalloc(work); > + kasan_record_aux_stack(work); > > preempt_disable(); > if (cpu !=3D smp_processor_id()) { > diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c > index b3b3ce34df631..4b3f319114650 100644 > --- a/kernel/rcu/tiny.c > +++ b/kernel/rcu/tiny.c > @@ -250,7 +250,7 @@ EXPORT_SYMBOL_GPL(poll_state_synchronize_rcu); > void kvfree_call_rcu(struct rcu_head *head, void *ptr) > { > if (head) > - kasan_record_aux_stack_noalloc(ptr); > + kasan_record_aux_stack(ptr); > > __kvfree_call_rcu(head, ptr); > } > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index b1f883fcd9185..7eae9bd818a90 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -3083,7 +3083,7 @@ __call_rcu_common(struct rcu_head *head, rcu_callba= ck_t func, bool lazy_in) > } > head->func =3D func; > head->next =3D NULL; > - kasan_record_aux_stack_noalloc(head); > + kasan_record_aux_stack(head); > local_irq_save(flags); > rdp =3D this_cpu_ptr(&rcu_data); > lazy =3D lazy_in && !rcu_async_should_hurry(); > @@ -3807,7 +3807,7 @@ void kvfree_call_rcu(struct rcu_head *head, void *p= tr) > return; > } > > - kasan_record_aux_stack_noalloc(ptr); > + kasan_record_aux_stack(ptr); > success =3D add_ptr_to_bulk_krc_lock(&krcp, &flags, ptr, !head); > if (!success) { > run_page_cache_worker(krcp); > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index a1c353a62c568..3717360a940d2 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -10485,7 +10485,7 @@ void task_tick_mm_cid(struct rq *rq, struct task_= struct *curr) > return; > > /* No page allocation under rq lock */ > - task_work_add(curr, work, TWA_RESUME | TWAF_NO_ALLOC); > + task_work_add(curr, work, TWA_RESUME); > } > > void sched_mm_cid_exit_signals(struct task_struct *t) > diff --git a/kernel/task_work.c b/kernel/task_work.c > index c969f1f26be58..d1efec571a4a4 100644 > --- a/kernel/task_work.c > +++ b/kernel/task_work.c > @@ -55,26 +55,14 @@ int task_work_add(struct task_struct *task, struct ca= llback_head *work, > enum task_work_notify_mode notify) > { > struct callback_head *head; > - int flags =3D notify & TWA_FLAGS; > > - notify &=3D ~TWA_FLAGS; > if (notify =3D=3D TWA_NMI_CURRENT) { > if (WARN_ON_ONCE(task !=3D current)) > return -EINVAL; > if (!IS_ENABLED(CONFIG_IRQ_WORK)) > return -EINVAL; > } else { > - /* > - * Record the work call stack in order to print it in KAS= AN > - * reports. > - * > - * Note that stack allocation can fail if TWAF_NO_ALLOC f= lag > - * is set and new page is needed to expand the stack buff= er. > - */ > - if (flags & TWAF_NO_ALLOC) > - kasan_record_aux_stack_noalloc(work); > - else > - kasan_record_aux_stack(work); > + kasan_record_aux_stack(work); > } > > head =3D READ_ONCE(task->task_works); > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index 9949ffad8df09..65b8314b2d538 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -2180,7 +2180,7 @@ static void insert_work(struct pool_workqueue *pwq,= struct work_struct *work, > debug_work_activate(work); > > /* record the work call stack in order to print it in KASAN repor= ts */ > - kasan_record_aux_stack_noalloc(work); > + kasan_record_aux_stack(work); > > /* we own @work, set data and link */ > set_work_pwq(work, pwq, extra_flags); > diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c > index 6310a180278b6..b18b5944997f8 100644 > --- a/mm/kasan/generic.c > +++ b/mm/kasan/generic.c > @@ -521,7 +521,7 @@ size_t kasan_metadata_size(struct kmem_cache *cache, = bool in_object) > sizeof(struct kasan_free_meta) : 0); > } > > -static void __kasan_record_aux_stack(void *addr, depot_flags_t depot_fla= gs) Could you add a comment here that notes the usage, something like: "This function avoids dynamic memory allocations and thus can be called from contexts that do not allow allocating memory." > +void kasan_record_aux_stack(void *addr) > { > struct slab *slab =3D kasan_addr_to_slab(addr); > struct kmem_cache *cache; > @@ -538,17 +538,7 @@ static void __kasan_record_aux_stack(void *addr, dep= ot_flags_t depot_flags) > return; > > alloc_meta->aux_stack[1] =3D alloc_meta->aux_stack[0]; > - alloc_meta->aux_stack[0] =3D kasan_save_stack(0, depot_flags); > -} > - > -void kasan_record_aux_stack(void *addr) > -{ > - return __kasan_record_aux_stack(addr, STACK_DEPOT_FLAG_CAN_ALLOC)= ; > -} > - > -void kasan_record_aux_stack_noalloc(void *addr) > -{ > - return __kasan_record_aux_stack(addr, 0); > + alloc_meta->aux_stack[0] =3D kasan_save_stack(0, 0); > } > > void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t= flags) > diff --git a/mm/slub.c b/mm/slub.c > index 5b832512044e3..b8c4bf3fe0d07 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -2300,7 +2300,7 @@ bool slab_free_hook(struct kmem_cache *s, void *x, = bool init, > * We have to do this manually because the rcu_he= ad is > * not located inside the object. > */ > - kasan_record_aux_stack_noalloc(x); > + kasan_record_aux_stack(x); > > delayed_free->object =3D x; > call_rcu(&delayed_free->head, slab_free_after_rcu= _debug); > -- > 2.45.2 > Otherwise, Reviewed-by: Andrey Konovalov Thank you!