https://bugzilla.kernel.org/show_bug.cgi?id=80981
Steps to reproduce:
strace dd if=/dev/urandom of=/dev/null bs=64M count=1
Before, dd did 1 read() syscall and returned full length.
Now, dd stops at 32 MB.
Signed-off-by: Alexey Dobriyan <adobri...@gmail.com>
---
STABLE needs 79a8468747c5f95ed3d5ce8376a3e82e0c5857fc
and this patch.
drivers/char/random.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1377,20 +1377,32 @@ random_read(struct file *file, char __user *buf, size_t
nbytes, loff_t *ppos)
}
static ssize_t
-urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
+urandom_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
- int ret;
+ ssize_t ret;
if (unlikely(nonblocking_pool.initialized == 0))
printk_once(KERN_NOTICE "random: %s urandom read "
"with %d bits of entropy available\n",
current->comm, nonblocking_pool.entropy_total);
- nbytes = min_t(size_t, nbytes, INT_MAX >> (ENTROPY_SHIFT + 3));
- ret = extract_entropy_user(&nonblocking_pool, buf, nbytes);
+ ret = 0;
+ while (count > 0) {
+ size_t count1;
+ ssize_t ret1;
+
+ count1 = min_t(size_t, count, INT_MAX >> (ENTROPY_SHIFT + 3));
+ ret1 = extract_entropy_user(&nonblocking_pool, buf, count1);
+ if (ret1 < 0)
+ return ret1;
- trace_urandom_read(8 * nbytes, ENTROPY_BITS(&nonblocking_pool),
- ENTROPY_BITS(&input_pool));
+ trace_urandom_read(8 * count1, ENTROPY_BITS(&nonblocking_pool),
+ ENTROPY_BITS(&input_pool));
+
+ buf += ret1;
+ count -= ret1;
+ ret += ret1;
+ }
return ret;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
