From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 50C201B21AF; Mon, 4 Nov 2024 11:45:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730720733; cv=none; b=E8nm8deEQ/AyKooHau2FgywCuvVXkiaC6IHdslryvRkoiETSJab7O9/ccpfCvlg0eYcCfwUwdho7qeB/aDyFUy+Bf1pC7t2u5thgoiSkWZBBAYcg/MluHXLXH0FCyHgWw/ssxTSU8rXApS0J74bKERljjGPQ/Y9GZkHzP7vvrBY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730720733; c=relaxed/simple; bh=KVDby3c7DfMjMMwDb+3rQ9nlHeE4Avrp8aPfYCVqQbE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZIUbDjhmXPKP5lhYfj9OzsgBygOZ5Gckpv9WHgYg6gUYjPNINKwd/YlEz+Bzn6qWTb6VZa8WDPLh/+OLy46FAhG37YgmCFde+JkLg+FOYSiQdJBvBJzrW+iD1WxvmWq1FuaFbPu3of0u3+B+GUQipYl5PxFzwD4M7x1gco7xyk4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=IQjV1Okq; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="IQjV1Okq" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=mYq2E5JqCpFxnnaQge2hIZbWTa3Or6pRl9pnrxRgOwA=; b=IQjV1OkqHH4Tgw5q5Eji03dmw3 CYzrCgtzK5De54IbL3dsTmmMV00KpBjzzyrd9Rav5/FvRwOWoT5aYiTTfLeXFE+qIRNjcH0BWWLf3 wrserS0aDM+kdcmlybZXwbOcswLILUastnrpSvGZZt/ZOyr3BP6zhuOmNNrRwLw5sQaR1qURtDl7P 7aCF5J2GJhYWD8oBN/QbCWTyoOQCZL/3DlREe+0XRCLSdYURbWVabK48l0jGxUHoOpxcq7M1Euhn6 bHMN2sb5h5Ib41iI5jQaQbsRxn+pH305Kxs50doIndy/CAHaHz2rYFR/V7T7islZ7nJIHcYsswWMi xNKEJQvA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1t7vW6-000000017vV-2NZE; Mon, 04 Nov 2024 11:45:07 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 58C81300324; Mon, 4 Nov 2024 12:45:06 +0100 (CET) Date: Mon, 4 Nov 2024 12:45:06 +0100 From: Peter Zijlstra To: Vlastimil Babka Cc: 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, Sebastian Andrzej Siewior , Marco Elver , Andrey Konovalov , 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, peterz@infradead.org, 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, vbabka@suse.cz, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, rcu@vger.kernel.org Subject: Re: [syzbot] [mm?] WARNING: locking bug in __rmqueue_pcplist Message-ID: <20241104114506.GC24862@noisy.programming.kicks-ass.net> References: <67275485.050a0220.3c8d68.0a37.GAE@google.com> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Nov 04, 2024 at 12:25:03PM +0100, Vlastimil Babka wrote: > On 11/4/24 12:11, Vlastimil Babka wrote: > >> __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4771 > >> alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265 > >> stack_depot_save_flags+0x666/0x830 lib/stackdepot.c:627 > >> kasan_save_stack+0x4f/0x60 mm/kasan/common.c:48 > >> __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:544 > >> task_work_add+0xd9/0x490 kernel/task_work.c:77 > > > > It seems the decision if stack depot is allowed to allocate here depends on > > TWAF_NO_ALLOC added only recently. So does it mean it doesn't work as intended? > > I guess __run_posix_cpu_timers() needs to pass TWAF_NO_ALLOC too? Yeah, or we just accept that kasan_record_aux_stack() is a horrible thing and shouldn't live in functions that try their bestest to locklessly setup async work at all. That thing has only ever caused trouble :/ Also see 156172a13ff0. How about we do the below at the very least? --- include/linux/kasan.h | 2 -- include/linux/task_work.h | 1 - kernel/irq_work.c | 2 +- kernel/rcu/tiny.c | 2 +- kernel/rcu/tree.c | 4 ++-- kernel/sched/core.c | 2 +- kernel/task_work.c | 12 +----------- kernel/workqueue.c | 2 +- mm/kasan/generic.c | 16 +++------------- mm/slub.c | 2 +- 10 files changed, 11 insertions(+), 34 deletions(-) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 00a3bf7c0d8f..1a623818e8b3 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -488,7 +488,6 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned 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_cache *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 2964171856e0..db1690e01346 100644 --- a/include/linux/task_work.h +++ b/include/linux/task_work.h @@ -21,7 +21,6 @@ enum task_work_notify_mode { TWA_NMI_CURRENT, TWA_FLAGS = 0xff00, - TWAF_NO_ALLOC = 0x0100, }; static inline bool task_work_pending(struct task_struct *task) diff --git a/kernel/irq_work.c b/kernel/irq_work.c index 2f4fb336dda1..73f7e1fd4ab4 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 != smp_processor_id()) { diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c index b3b3ce34df63..4b3f31911465 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 b1f883fcd918..7eae9bd818a9 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3083,7 +3083,7 @@ __call_rcu_common(struct rcu_head *head, rcu_callback_t func, bool lazy_in) } head->func = func; head->next = NULL; - kasan_record_aux_stack_noalloc(head); + kasan_record_aux_stack(head); local_irq_save(flags); rdp = this_cpu_ptr(&rcu_data); lazy = lazy_in && !rcu_async_should_hurry(); @@ -3807,7 +3807,7 @@ void kvfree_call_rcu(struct rcu_head *head, void *ptr) return; } - kasan_record_aux_stack_noalloc(ptr); + kasan_record_aux_stack(ptr); success = 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 5de31c312189..dafc668a156e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -10519,7 +10519,7 @@ 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 c969f1f26be5..2ffd5a6db91b 100644 --- a/kernel/task_work.c +++ b/kernel/task_work.c @@ -64,17 +64,7 @@ int task_work_add(struct task_struct *task, struct callback_head *work, if (!IS_ENABLED(CONFIG_IRQ_WORK)) return -EINVAL; } else { - /* - * Record the work call stack in order to print it in KASAN - * reports. - * - * Note that stack allocation can fail if TWAF_NO_ALLOC flag - * is set and new page is needed to expand the stack buffer. - */ - if (flags & TWAF_NO_ALLOC) - kasan_record_aux_stack_noalloc(work); - else - kasan_record_aux_stack(work); + kasan_record_aux_stack(work); } head = READ_ONCE(task->task_works); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 9949ffad8df0..65b8314b2d53 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 reports */ - 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 6310a180278b..ac9f6682bb2f 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -521,12 +521,12 @@ 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_flags) +void kasan_record_aux_stack(void *addr) { struct slab *slab = kasan_addr_to_slab(addr); struct kmem_cache *cache; struct kasan_alloc_meta *alloc_meta; - void *object; + void *object if (is_kfence_address(addr) || !slab) return; @@ -538,17 +538,7 @@ static void __kasan_record_aux_stack(void *addr, depot_flags_t depot_flags) return; alloc_meta->aux_stack[1] = alloc_meta->aux_stack[0]; - alloc_meta->aux_stack[0] = 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] = 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 5b832512044e..b8c4bf3fe0d0 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_head is * not located inside the object. */ - kasan_record_aux_stack_noalloc(x); + kasan_record_aux_stack(x); delayed_free->object = x; call_rcu(&delayed_free->head, slab_free_after_rcu_debug);