Merge tag 'asoc-v5.1' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-next

ASoC: Updates for v5.1

Lots and lots of new drivers so far, a highlight being the MediaTek
BTCVSD which is a driver for a Bluetooth radio chip - the first such
driver we've had upstream.  Hopefully we will soon also see a baseband
with an upstream driver!

 - Support for only powering up channels that are actively being used.
 - Quite a few improvements to simplify the generic card drivers,
   especially the merge of the SCU cards into the main generic drivers.
 - Lots of fixes for probing on Intel systems, trying to rationalize
   things to look more standard from a framework point of view.
 - New drivers for Asahi Kasei Microdevices AK4497, Cirrus Logic CS4341,
   Google ChromeOS embedded controllers, Ingenic JZ4725B, MediaTek
   BTCVSD, MT8183 and MT6358, NXP MICFIL, Rockchip RK3328, Spreadtrum
   DMA controllers, Qualcomm WCD9335, Xilinx S/PDIF and PCM formatters.

1 files changed, 12 insertions, 2 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index a60459947f18..b69248e6f0e0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -217,6 +217,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
                 memset(s->addr, 0, THREAD_SIZE);
 
                 tsk->stack_vm_area = s;
+                tsk->stack = s->addr;
                 return s->addr;
         }
 
@@ -1833,8 +1834,6 @@ static __latent_entropy struct task_struct *copy_process(
 
         posix_cpu_timers_init(p);
 
-        p->start_time = ktime_get_ns();
-        p->real_start_time = ktime_get_boot_ns();
         p->io_context = NULL;
         audit_set_context(p, NULL);
         cgroup_fork(p);
@@ -2001,6 +2000,17 @@ static __latent_entropy struct task_struct *copy_process(
                 goto bad_fork_free_pid;
 
         /*
+         * From this point on we must avoid any synchronous user-space
+         * communication until we take the tasklist-lock. In particular, we do
+         * not want user-space to be able to predict the process start-time by
+         * stalling fork(2) after we recorded the start_time but before it is
+         * visible to the system.
+         */
+
+        p->start_time = ktime_get_ns();
+        p->real_start_time = ktime_get_boot_ns();
+
+        /*
          * Make it visible to the rest of the system, but dont wake it up yet.
          * Need tasklist lock for parent etc handling!
          */