Re: [syzbot] BUG: sleeping function called from invalid context in crypto_drop_spawn (2)

[Hillf Danton <hdanton@sina.com>]

On Thu, 01 Jul 2021 21:33:24 -0700
>syzbot found the following issue on:
>
>HEAD commit:    d6765985 Revert "be2net: disable bh with spin_lock in be_p..
>git tree:       net
>console output: https://syzkaller.appspot.com/x/log.txt?x=1555a0d8300000
>kernel config:  https://syzkaller.appspot.com/x/.config?x=7ca96a2d153c74b0
>dashboard link: https://syzkaller.appspot.com/bug?extid=610ec0671f51e838436e
>
>Unfortunately, I don't have any reproducer for this issue yet.
>
>IMPORTANT: if you fix the issue, please add the following tag to the commit:
>Reported-by: syzbot+610ec0671f51e838436e@syzkaller.appspotmail.com
>
>BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1405
>in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1180, name: kworker/u4:6
>4 locks held by kworker/u4:6/1180:
> #0: ffff88802897e138 ((wq_completion)bat_events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
> #0: ffff88802897e138 ((wq_completion)bat_events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
> #0: ffff88802897e138 ((wq_completion)bat_events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
> #0: ffff88802897e138 ((wq_completion)bat_events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:617 [inline]
> #0: ffff88802897e138 ((wq_completion)bat_events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
> #0: ffff88802897e138 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x871/0x1600 kernel/workqueue.c:2247
> #1: ffffc90004ecfda8 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x1600 kernel/workqueue.c:2251
> #2: ffffffff8bf79620 (rcu_read_lock){....}-{1:2}, at: batadv_nc_process_nc_paths.part.0+0xb1/0x3b0 net/batman-adv/network-coding.c:680
> #3: ffffffff8bf79500 (rcu_callback){....}-{0:0}, at: rcu_do_batch kernel/rcu/tree.c:2547 [inline]
> #3: ffffffff8bf79500 (rcu_callback){....}-{0:0}, at: rcu_core+0x737/0x13b0 kernel/rcu/tree.c:2793
>Preemption disabled at:
>[<0000000000000000>] 0x0
>CPU: 1 PID: 1180 Comm: kworker/u4:6 Not tainted 5.13.0-rc6-syzkaller #0
>Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
>Workqueue: bat_events batadv_nc_worker
>Call Trace:
> <IRQ>
> __dump_stack lib/dump_stack.c:79 [inline]
> dump_stack+0x141/0x1d7 lib/dump_stack.c:120
> ___might_sleep.cold+0x1f1/0x237 kernel/sched/core.c:8337
> down_write+0x6e/0x150 kernel/locking/rwsem.c:1405
> crypto_drop_spawn crypto/algapi.c:709 [inline]
> crypto_drop_spawn+0x4b/0x2b0 crypto/algapi.c:704
> crypto_drop_aead include/crypto/internal/aead.h:90 [inline]
> pcrypt_free+0x15/0x80 crypto/pcrypt.c:206
> crypto_free_instance crypto/algapi.c:68 [inline]
> crypto_destroy_instance+0x7a/0xc0 crypto/algapi.c:76
> crypto_alg_put crypto/internal.h:108 [inline]
> crypto_alg_put crypto/internal.h:105 [inline]
> crypto_mod_put+0xd3/0x100 crypto/api.c:45
> crypto_destroy_tfm crypto/api.c:573 [inline]
> crypto_destroy_tfm+0xdb/0x240 crypto/api.c:561
> crypto_free_aead include/crypto/aead.h:193 [inline]
> tipc_aead_free+0x398/0x660 net/tipc/crypto.c:422
> rcu_do_batch kernel/rcu/tree.c:2558 [inline]
> rcu_core+0x7ab/0x13b0 kernel/rcu/tree.c:2793
> __do_softirq+0x29b/0x9f6 kernel/softirq.c:559
> invoke_softirq kernel/softirq.c:433 [inline]
> __irq_exit_rcu+0x136/0x200 kernel/softirq.c:637
> irq_exit_rcu+0x5/0x20 kernel/softirq.c:649
> sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100
> </IRQ>
> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:647
>RIP: 0010:check_preemption_disabled+0x2a/0x150 lib/smp_processor_id.c:16
>Code: 41 56 41 55 49 89 f5 41 54 55 48 89 fd 53 0f 1f 44 00 00 65 44 8b 25 1d 7a ea 76 65 8b 1d 6e d4 ea 76 81 e3 ff ff ff 7f 31 ff <89> de 0f 1f 44 00 00 85 db 74 11 0f 1f 44 00 00 44 89 e0 5b 5d 41
>RSP: 0018:ffffc90004ecfbd8 EFLAGS: 00000246
>RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
>RDX: ffff888017ed3880 RSI: ffffffff89c2e880 RDI: 0000000000000000
>RBP: ffffffff89c2e8c0 R08: 0000000000000000 R09: 0000000000000000
>R10: ffffffff88b6951d R11: 0000000000000000 R12: 0000000000000001
>R13: ffffffff89c2e880 R14: ffff88803029cc00 R15: 000000000000001f
> rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:325 [inline]
> rcu_is_watching+0xe/0xc0 kernel/rcu/tree.c:1168
> rcu_read_unlock include/linux/rcupdate.h:707 [inline]
> batadv_nc_process_nc_paths.part.0+0x304/0x3b0 net/batman-adv/network-coding.c:695
> batadv_nc_process_nc_paths net/batman-adv/network-coding.c:675 [inline]
> batadv_nc_worker+0xb90/0xe50 net/batman-adv/network-coding.c:731
> process_one_work+0x98d/0x1600 kernel/workqueue.c:2276
> worker_thread+0x64c/0x1120 kernel/workqueue.c:2422
> kthread+0x3b1/0x4a0 kernel/kthread.c:313
> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

In a bid to fix the reported BUG, move freeing aead to workqueue to
avoid scheduling on the softint stack.

+++ x/net/tipc/crypto.c
@@ -399,13 +399,9 @@ static inline void tipc_aead_put(struct
 		call_rcu(&aead->rcu, tipc_aead_free);
 }
 
-/**
- * tipc_aead_free - Release AEAD key incl. all the TFMs in the list
- * @rp: rcu head pointer
- */
-static void tipc_aead_free(struct rcu_head *rp)
+static void tipc_aead_free_workfn(struct work_struct *w)
 {
-	struct tipc_aead *aead = container_of(rp, struct tipc_aead, rcu);
+	struct tipc_aead *aead = container_of(w, struct tipc_aead, free_work);
 	struct tipc_tfm *tfm_entry, *head, *tmp;
 
 	if (aead->cloned) {
@@ -428,6 +424,18 @@ static void tipc_aead_free(struct rcu_he
 	kfree(aead);
 }
 
+/**
+ * tipc_aead_free - Release AEAD key incl. all the TFMs in the list
+ * @rp: rcu head pointer
+ */
+static void tipc_aead_free(struct rcu_head *r)
+{
+	struct tipc_aead *aead = container_of(r, struct tipc_aead, rcu);
+
+	INIT_WORK(&aead->free_work, tipc_aead_free_workfn);
+	queue_work(system_unbound_wq, &aead->free_work);
+}
+
 static int tipc_aead_users(struct tipc_aead __rcu *aead)
 {
 	struct tipc_aead *tmp;