lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Tue, 19 Oct 2021 15:23:01 -0000
From:   "tip-bot2 for Woody Lin" <>
Cc:     Woody Lin <>,
        "Peter Zijlstra (Intel)" <>,
        Valentin Schneider <>,,
Subject: [tip: sched/urgent] sched/scs: Reset the shadow stack when idle_task_exit

The following commit has been merged into the sched/urgent branch of tip:

Commit-ID:     45dfb89b8f96643268449c25d7025b17de46717c
Author:        Woody Lin <>
AuthorDate:    Tue, 12 Oct 2021 16:35:21 +08:00
Committer:     Peter Zijlstra <>
CommitterDate: Mon, 18 Oct 2021 16:58:41 +02:00

sched/scs: Reset the shadow stack when idle_task_exit

There was a 'init_idle' that resets scs sp to base, but is removed by
f1a0a376ca0c. Without the resetting, the hot-plugging implemented by
cpu_psci_cpu_boot will use the previous scs sp as new base when starting
up a CPU core, so the usage on scs page is being stacked up until

This only happens on idle task since __cpu_up is using idle task as the
main thread to start up a CPU core, so the overflow can be fixed by
resetting scs sp to base in 'idle_task_exit'.

Fixes: f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled")
Signed-off-by: Woody Lin <>
Signed-off-by: Peter Zijlstra (Intel) <>
Reviewed-by: Valentin Schneider <>
 kernel/sched/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 1bba412..f21714e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8795,6 +8795,7 @@ void idle_task_exit(void)
+	scs_task_reset(current);
 	/* finish_cpu(), as ran on the BP, will clean up the active_mm state */

Powered by blists - more mailing lists