On Tue, Apr 25, 2017 at 10:46:46AM -0500, Julia Cartwright wrote:
> On Mon, Apr 24, 2017 at 04:33:35PM +0300, Alexander GQ Gerasiov wrote:
> > From: Alexander GQ Gerasiov <gq@xxxxxxxxxxx>
>
> Hello Alexander-
>
> > This commit fixes the following warning:
>
> In general, with the class of "convert to raw spinlock" patches, it's
> nice to have written affirmation in the commit message that you've
> looked through all of the codepaths and ensured bounded, minimal
> behavior.
>
> > [ ] BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:993
> > [ ] in_atomic(): 0, irqs_disabled(): 1, pid: 58, name: kworker/u12:1
> > [ ] CPU: 5 PID: 58 Comm: kworker/u12:1 Tainted: G W 4.9.20-rt16-stand6-686 #1
> > [ ] Hardware name: Supermicro SYS-5027R-WRF/X9SRW-F, BIOS 3.2a 10/28/2015
> > [ ] Workqueue: writeback wb_workfn (flush-253:0)
> > [ ] edf21a34 c12cdc6f c1078f0a edf08c40 edf21a64 c10787c1 c1668778 00000000
> > [ ] 00000001 0000003a edf09144 00000000 80000000 ec694b18 ec775748 ec694ad0
> > [ ] edf21a70 c1584587 ec775790 edf21ac4 f893e8a3 00000000 c1078e52 00000000
> > [ ] Call Trace:
> > [ ] [<c12cdc6f>] dump_stack+0x47/0x68
> > [ ] [<c1078f0a>] ? migrate_enable+0x4a/0xf0
> > [ ] [<c10787c1>] ___might_sleep+0x101/0x180
> > [ ] [<c1584587>] rt_spin_lock+0x17/0x40
> > [ ] [<f893e8a3>] add_stripe_bio+0x4e3/0x6c0 [raid456]
> > [ ] [<c1078e52>] ? preempt_count_add+0x42/0xb0
> > [ ] [<f89408f7>] raid5_make_request+0x737/0xdd0 [raid456]
>
> Did you cut off the bottom of the callstack, here?
Looking at this some more, I imagine the callpath which is problematic
is:
<writeback kworker>
...
add_stripe_bio()
stripe_add_to_batch_list()
lock_two_stripes()
local_irq_disable()
spin_lock(&sh{1,2}->stripe_lock) --> ___might_sleep() --> BOOM
That is, it's the local_irq_disable() in lock_two_stripes() which is the
problem. That's my gut feel, anyway. Can you give this patch a try and
see if works? You'll probably still want the second patch in your
series.
Julia
-- 8< --
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index fa2c4de32a64..54dc2995aeee 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -110,8 +110,7 @@ static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
{
int i;
- local_irq_disable();
- spin_lock(conf->hash_locks);
+ spin_lock_irq(conf->hash_locks);
for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
spin_lock(&conf->device_lock);
@@ -121,9 +120,9 @@ static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
{
int i;
spin_unlock(&conf->device_lock);
- for (i = NR_STRIPE_HASH_LOCKS; i; i--)
- spin_unlock(conf->hash_locks + i - 1);
- local_irq_enable();
+ for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
+ spin_unlock(conf->hash_locks + i);
+ spin_unlock_irq(conf->hash_locks);
}
/* bio's attached to a stripe+device for I/O are linked together in bi_sector
@@ -732,12 +731,11 @@ static bool is_full_stripe_write(struct stripe_head *sh)
static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
{
- local_irq_disable();
if (sh1 > sh2) {
- spin_lock(&sh2->stripe_lock);
+ spin_lock_irq(&sh2->stripe_lock);
spin_lock_nested(&sh1->stripe_lock, 1);
} else {
- spin_lock(&sh1->stripe_lock);
+ spin_lock_irq(&sh1->stripe_lock);
spin_lock_nested(&sh2->stripe_lock, 1);
}
}
@@ -745,8 +743,7 @@ static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
{
spin_unlock(&sh1->stripe_lock);
- spin_unlock(&sh2->stripe_lock);
- local_irq_enable();
+ spin_unlock_irq(&sh2->stripe_lock);
}
/* Only freshly new full stripe normal write stripe can be added to a batch list */
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