Commit d40797d6 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Andrew Morton
Browse files

kasan: make kasan_record_aux_stack_noalloc() the default behaviour 

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 To quote Marco Elver from
https://lore.kernel.org/all/CANpmjNPmQYJ7pv1N3cuU8cP18u7PP_uoZD8YxwZd4jtbof9nVQ@mail.gmail.com/

| I'd be in favor, it simplifies things. And stack depot should be
| able to replenish its pool sufficiently in the "non-aux" cases
| i.e. regular allocations. Worst case we fail to record some
| aux stacks, but I think that's only really bad if there's a bug
| around one of these allocations. In general the probabilities
| of this being a regression are extremely small [...]

Make the kasan_record_aux_stack_noalloc() behaviour default as
kasan_record_aux_stack().

[bigeasy@linutronix.de: dressed the diff as patch]
Link: https://lkml.kernel.org/r/20241122155451.Mb2pmeyJ@linutronix.de


Fixes: 7cb3007c ("kasan: generic: introduce kasan_record_aux_stack_noalloc()")
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: default avatar <syzbot+39f85d612b7c20d8db48@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/all/67275485.050a0220.3c8d68.0a37.GAE@google.com


Reviewed-by: default avatarAndrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Reviewed-by: default avatarWaiman Long <longman@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: <kasan-dev@googlegroups.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: syzkaller-bugs@googlegroups.com
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 773fc6ab

include/linux/kasan.h

+0 −2
Original line number Diff line number Diff line
@@ -491,7 +491,6 @@ 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 */
@@ -509,7 +508,6 @@ 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 */

include/linux/task_work.h

+0 −3
Original line number Diff line number Diff line
@@ -19,9 +19,6 @@ enum task_work_notify_mode { 
	TWA_SIGNAL,

	TWA_SIGNAL_NO_IPI,

	TWA_NMI_CURRENT,



	TWA_FLAGS = 0xff00,

	TWAF_NO_ALLOC = 0x0100,

};



static inline bool task_work_pending(struct task_struct *task)

kernel/irq_work.c

+1 −1
Original line number Diff line number Diff line
@@ -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()) {

kernel/rcu/tiny.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

}

kernel/rcu/tree.c

+2 −2
Original line number Diff line number Diff line
@@ -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();
@@ -3817,7 +3817,7 @@ 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);