@@ -513,8 +513,13 @@ static int hwrng_fillfn(void *unused)
break;
if (rc <= 0) {
- pr_warn("hwrng: no data available\n");
- msleep_interruptible(10000);
+ int i;
+
+ for (i = 0; i < 100; ++i) {
+ if (kthread_should_stop() ||
+ msleep_interruptible(10000 / 100))
+ goto out;
+ }
continue;
}
@@ -529,6 +534,7 @@ static int hwrng_fillfn(void *unused)
add_hwgenerator_randomness((void *)rng_fillbuf, rc,
entropy >> 10);
}
+out:
hwrng_fill = NULL;
return 0;
}
@@ -52,20 +52,6 @@ static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size)
return j << 2;
}
-static u32 ath9k_rng_delay_get(u32 fail_stats)
-{
- u32 delay;
-
- if (fail_stats < 100)
- delay = 10;
- else if (fail_stats < 105)
- delay = 1000;
- else
- delay = 10000;
-
- return delay;
-}
-
static int ath9k_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
{
struct ath_softc *sc = container_of(rng, struct ath_softc, rng_ops);
@@ -80,10 +66,9 @@ static int ath9k_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
bytes_read += max & 3UL;
memzero_explicit(&word, sizeof(word));
}
- if (!wait || !max || likely(bytes_read) || fail_stats > 110)
+ if (!wait || !max || likely(bytes_read) ||
+ ++fail_stats >= 100 || msleep_interruptible(5))
break;
-
- msleep_interruptible(ath9k_rng_delay_get(++fail_stats));
}
if (wait && !bytes_read && max)
Even though hwrng provides a `wait` parameter, it doesn't work very well when waiting for a long time. There are numerous deadlocks that emerge related to shutdown. Work around this API limitation by waiting for a shorter amount of time and erroring more frequently. This commit also prevents hwrng from splatting messages to dmesg when there's a timeout and prevents calling msleep_interruptible() for tons of time when a thread is supposed to be shutting down, since msleep_interruptible() isn't actually interrupted by kthread_stop(). Reported-by: Gregory Erwin <gregerwin256@gmail.com> Cc: Toke Høiland-Jørgensen <toke@redhat.com> Cc: Kalle Valo <kvalo@kernel.org> Cc: Rui Salvaterra <rsalvaterra@gmail.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: stable@vger.kernel.org Fixes: fcd09c90c3c5 ("ath9k: use hw_random API instead of directly dumping into random.c") Link: https://lore.kernel.org/all/CAO+Okf6ZJC5-nTE_EJUGQtd8JiCkiEHytGgDsFGTEjs0c00giw@mail.gmail.com/ Link: https://lore.kernel.org/lkml/CAO+Okf5k+C+SE6pMVfPf-d8MfVPVq4PO7EY8Hys_DVXtent3HA@mail.gmail.com/ Link: https://bugs.archlinux.org/task/75138 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> --- I do not have an ath9k and therefore I can't test this myself. The analysis above was done completely statically, with no dynamic tracing and just a bug report of symptoms from Gregory. So it might be totally wrong. Thus, this patch very much requires Gregory's testing. Please don't apply it until we have his `Tested-by` line. drivers/char/hw_random/core.c | 10 ++++++++-- drivers/net/wireless/ath/ath9k/rng.c | 19 ++----------------- 2 files changed, 10 insertions(+), 19 deletions(-)