Quoting Keerthy (2019-08-18 21:24:58)
> Hi Stephen,
>
> commit 03a3bb7ae63150230c5de645dc95e673ebf17e1a
> Author: Stephen Boyd <swboyd@xxxxxxxxxxxx>
> Date: Mon Aug 5 16:32:41 2019 -0700
>
> hwrng: core - Freeze khwrng thread during suspend
>
> Commit seems to be breaking suspend/resume on TI AM43/AM33 platforms.
>
>
> rtcwake: wakeup from "mem" using /dev/rtc0 at Sun Nov 18 02:12:12 2018
> [ 54.033833] PM: suspend entry (deep)
> [ 54.037741] Filesystems sync: 0.000 seconds
> [ 54.062730] Freezing user space processes ... (elapsed 0.001 seconds)
> done.
> [ 54.071313] OOM killer disabled.
> [ 54.074572] Freezing remaining freezable tasks ...
> [ 74.083121] Freezing of tasks failed after 20.003 seconds (1 tasks
> refusing to freeze, wq_busy=0):
> [ 74.092257] hwrng R running task 0 289 2
> 0x00000020
> [ 74.099511] [<c08c64c4>] (__schedule) from [<c08c6a10>]
> (schedule+0x3c/0xc0)
> [ 74.106720] [<c08c6a10>] (schedule) from [<c05dbd8c>]
> (add_hwgenerator_randomness+0xb0/0x100)
> [ 74.115358] [<c05dbd8c>] (add_hwgenerator_randomness) from
> [<bf1803c8>] (hwrng_fillfn+0xc0/0x14c [rng_core])
Thanks for the report. I suspect we need to check for freezer in
add_hwgenerator_randomness(). I find it odd that there's another caller
of add_hwgenerator_randomness(), but maybe the ath9k driver can be
converted to some sort of hwrng driver instead of calling into the
kthread directly.
Anyway, can you try this patch?
---8<---
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 5d5ea4ce1442..e2e85ca16410 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2429,6 +2429,7 @@ void add_hwgenerator_randomness(const char *buffer, size_t count,
size_t entropy)
{
struct entropy_store *poolp = &input_pool;
+ bool frozen = false;
if (unlikely(crng_init == 0)) {
crng_fast_load(buffer, count);
@@ -2439,9 +2440,12 @@ void add_hwgenerator_randomness(const char *buffer, size_t count,
* We'll be woken up again once below random_write_wakeup_thresh,
* or when the calling thread is about to terminate.
*/
- wait_event_interruptible(random_write_wait, kthread_should_stop() ||
+ wait_event_interruptible(random_write_wait,
+ kthread_freezable_should_stop(&frozen) ||
ENTROPY_BITS(&input_pool) <= random_write_wakeup_bits);
- mix_pool_bytes(poolp, buffer, count);
- credit_entropy_bits(poolp, entropy);
+ if (!frozen) {
+ mix_pool_bytes(poolp, buffer, count);
+ credit_entropy_bits(poolp, entropy);
+ }
}
EXPORT_SYMBOL_GPL(add_hwgenerator_randomness);
