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* Question on KASAN calltrace record in RT
@ 2021-04-06  8:26 Zhang, Qiang
  2021-04-13 15:29 ` Dmitry Vyukov
  0 siblings, 1 reply; 13+ messages in thread
From: Zhang, Qiang @ 2021-04-06  8:26 UTC (permalink / raw)
  To: Andrew Halaney, andreyknvl, ryabinin.a.a, dvyukov, andreyknvl, akpm
  Cc: linux-kernel, kasan-dev

Hello everyone

In RT system,   after  Andrew test,   found the following calltrace ,
in KASAN, we record callstack through stack_depot_save(), in this function, may be call alloc_pages,  but in RT, the spin_lock replace with 
rt_mutex in alloc_pages(), if before call this function, the irq is disabled,
will trigger following calltrace.

maybe  add array[KASAN_STACK_DEPTH] in struct kasan_track to record callstack  in RT system.

Is there a better solution ？
Thanks
Qiang

BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:951
[   14.522262] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 640, name: mount
[   14.522304] Call Trace:
[   14.522306]  dump_stack+0x92/0xc1
[   14.522313]  ___might_sleep.cold.99+0x1b0/0x1ef
[   14.522319]  rt_spin_lock+0x3e/0xc0
[   14.522329]  local_lock_acquire+0x52/0x3c0
[   14.522332]  get_page_from_freelist+0x176c/0x3fd0
[   14.522543]  __alloc_pages_nodemask+0x28f/0x7f0
[   14.522559]  stack_depot_save+0x3a1/0x470
[   14.522564]  kasan_save_stack+0x2f/0x40
[   14.523575]  kasan_record_aux_stack+0xa3/0xb0
[   14.523580]  insert_work+0x48/0x340
[   14.523589]  __queue_work+0x430/0x1280
[   14.523595]  mod_delayed_work_on+0x98/0xf0
[   14.523607]  kblockd_mod_delayed_work_on+0x17/0x20
[   14.523611]  blk_mq_run_hw_queue+0x151/0x2b0
[   14.523620]  blk_mq_sched_insert_request+0x2ad/0x470
[   14.523633]  blk_mq_submit_bio+0xd2a/0x2330
[   14.523675]  submit_bio_noacct+0x8aa/0xfe0
[   14.523693]  submit_bio+0xf0/0x550
[   14.523714]  submit_bio_wait+0xfe/0x200
[   14.523724]  xfs_rw_bdev+0x370/0x480 [xfs]
[   14.523831]  xlog_do_io+0x155/0x320 [xfs]
[   14.524032]  xlog_bread+0x23/0xb0 [xfs]
[   14.524133]  xlog_find_head+0x131/0x8b0 [xfs]
[   14.524375]  xlog_find_tail+0xc8/0x7b0 [xfs]
[   14.524828]  xfs_log_mount+0x379/0x660 [xfs]
[   14.524927]  xfs_mountfs+0xc93/0x1af0 [xfs]
[   14.525424]  xfs_fs_fill_super+0x923/0x17f0 [xfs]
[   14.525522]  get_tree_bdev+0x404/0x680
[   14.525622]  vfs_get_tree+0x89/0x2d0
[   14.525628]  path_mount+0xeb2/0x19d0
[   14.525648]  do_mount+0xcb/0xf0
[   14.525665]  __x64_sys_mount+0x162/0x1b0
[   14.525670]  do_syscall_64+0x33/0x40
[   14.525674]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   14.525677] RIP: 0033:0x7fd6c15eaade

^ permalink raw reply	[flat|nested] 13+ messages in thread
* [patch] kasan: Make it RT aware
@ 2021-08-21  6:48 Mike Galbraith
  0 siblings, 0 replies; 13+ messages in thread
From: Mike Galbraith @ 2021-08-21  6:48 UTC (permalink / raw)
  To: linux-rt-users; +Cc: Sebastian Andrzej Siewior, Thomas Gleixner


Skip preallocation when not possible for RT, and move cache removal
from IPI, where freeing is not possible for RT, to synchronous work.

Signed-off-by: Mike Galbraith <efault@gmx.de>
---
 lib/stackdepot.c      |    4 ++--
 mm/kasan/quarantine.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 2 deletions(-)

--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -265,7 +265,7 @@ depot_stack_handle_t stack_depot_save(un
 	struct page *page = NULL;
 	void *prealloc = NULL;
 	unsigned long flags;
-	u32 hash;
+	u32 hash, may_prealloc = !IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible();

 	if (unlikely(nr_entries == 0) || stack_depot_disable)
 		goto fast_exit;
@@ -291,7 +291,7 @@ depot_stack_handle_t stack_depot_save(un
 	 * The smp_load_acquire() here pairs with smp_store_release() to
 	 * |next_slab_inited| in depot_alloc_stack() and init_stack_slab().
 	 */
-	if (unlikely(!smp_load_acquire(&next_slab_inited))) {
+	if (unlikely(!smp_load_acquire(&next_slab_inited) && may_prealloc)) {
 		/*
 		 * Zero out zone modifiers, as we don't have specific zone
 		 * requirements. Keep the flags related to allocation in atomic
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -19,6 +19,9 @@
 #include <linux/srcu.h>
 #include <linux/string.h>
 #include <linux/types.h>
+#include <linux/cpu.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
 #include <linux/cpuhotplug.h>

 #include "../slab.h"
@@ -308,6 +311,48 @@ static void per_cpu_remove_cache(void *a
 	qlist_free_all(&to_free, cache);
 }

+#ifdef CONFIG_PREEMPT_RT
+struct remove_cache_work {
+	struct work_struct work;
+	struct kmem_cache *cache;
+};
+
+static DEFINE_MUTEX(remove_caches_lock);
+static DEFINE_PER_CPU(struct remove_cache_work, remove_cache_work);
+
+static void per_cpu_remove_cache_work(struct work_struct *w)
+{
+	struct remove_cache_work *rcw;
+
+	rcw = container_of(w, struct remove_cache_work, work);
+	per_cpu_remove_cache(rcw->cache);
+}
+
+static void per_cpu_remove_caches_sync(struct kmem_cache *cache)
+{
+	struct remove_cache_work *rcw;
+	unsigned int cpu;
+
+	cpus_read_lock();
+	mutex_lock(&remove_caches_lock);
+
+	for_each_online_cpu(cpu) {
+		rcw = &per_cpu(remove_cache_work, cpu);
+		INIT_WORK(&rcw->work, per_cpu_remove_cache_work);
+		rcw->cache = cache;
+		schedule_work_on(cpu, &rcw->work);
+	}
+
+	for_each_online_cpu(cpu) {
+		rcw = &per_cpu(remove_cache_work, cpu);
+		flush_work(&rcw->work);
+	}
+
+	mutex_unlock(&remove_caches_lock);
+	cpus_read_unlock();
+}
+#endif
+
 /* Free all quarantined objects belonging to cache. */
 void kasan_quarantine_remove_cache(struct kmem_cache *cache)
 {
@@ -321,7 +366,11 @@ void kasan_quarantine_remove_cache(struc
 	 * achieves the first goal, while synchronize_srcu() achieves the
 	 * second.
 	 */
+#ifndef CONFIG_PREEMPT_RT
 	on_each_cpu(per_cpu_remove_cache, cache, 1);
+#else
+	per_cpu_remove_caches_sync(cache);
+#endif

 	raw_spin_lock_irqsave(&quarantine_lock, flags);
 	for (i = 0; i < QUARANTINE_BATCHES; i++) {



^ permalink raw reply	[flat|nested] 13+ messages in thread
end of thread, other threads:[~2021-08-21  6:49 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-06  8:26 Question on KASAN calltrace record in RT Zhang, Qiang
2021-04-13 15:29 ` Dmitry Vyukov
2021-04-14  4:00   ` Mike Galbraith
2021-04-14  5:26     ` Dmitry Vyukov
2021-04-14  6:15       ` Mike Galbraith
2021-04-14 15:04         ` [patch] kasan: make it RT aware Mike Galbraith
2021-04-15 18:13       ` Question on KASAN calltrace record in RT Mike Galbraith
2021-04-14  7:29     ` 回复: " Zhang, Qiang
2021-04-14  7:56       ` Mike Galbraith
2021-04-14  8:09         ` 回复: " Zhang, Qiang
2021-04-14  6:58   ` Zhang, Qiang
2021-04-14  7:07     ` Dmitry Vyukov
2021-08-21  6:48 [patch] kasan: Make it RT aware Mike Galbraith

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