From 2f7c68cb55ecb7331f2381deb497c27155f32faf Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 03 Jan 2024 09:43:39 +0000
Subject: [PATCH] update kernel to 5.10.198
---
kernel/kernel/futex/core.c | 28 ++++++++++++++++++----------
1 files changed, 18 insertions(+), 10 deletions(-)
diff --git a/kernel/kernel/futex.c b/kernel/kernel/futex/core.c
similarity index 98%
rename from kernel/kernel/futex.c
rename to kernel/kernel/futex/core.c
index b223cc5..78cc66b 100644
--- a/kernel/kernel/futex.c
+++ b/kernel/kernel/futex/core.c
@@ -42,7 +42,7 @@
#include <asm/futex.h>
-#include "locking/rtmutex_common.h"
+#include "../locking/rtmutex_common.h"
#include <trace/hooks/futex.h>
/*
@@ -3417,6 +3417,7 @@
bool pi, bool pending_op)
{
u32 uval, nval, mval;
+ pid_t owner;
int err;
/* Futex address must be 32bit aligned */
@@ -3438,6 +3439,10 @@
* 2. A woken up waiter is killed before it can acquire the
* futex in user space.
*
+ * In the second case, the wake up notification could be generated
+ * by the unlock path in user space after setting the futex value
+ * to zero or by the kernel after setting the OWNER_DIED bit below.
+ *
* In both cases the TID validation below prevents a wakeup of
* potential waiters which can cause these waiters to block
* forever.
@@ -3446,24 +3451,27 @@
*
* 1) task->robust_list->list_op_pending != NULL
* @pending_op == true
- * 2) User space futex value == 0
+ * 2) The owner part of user space futex value == 0
* 3) Regular futex: @pi == false
*
* If these conditions are met, it is safe to attempt waking up a
* potential waiter without touching the user space futex value and
- * trying to set the OWNER_DIED bit. The user space futex value is
- * uncontended and the rest of the user space mutex state is
- * consistent, so a woken waiter will just take over the
- * uncontended futex. Setting the OWNER_DIED bit would create
- * inconsistent state and malfunction of the user space owner died
- * handling.
+ * trying to set the OWNER_DIED bit. If the futex value is zero,
+ * the rest of the user space mutex state is consistent, so a woken
+ * waiter will just take over the uncontended futex. Setting the
+ * OWNER_DIED bit would create inconsistent state and malfunction
+ * of the user space owner died handling. Otherwise, the OWNER_DIED
+ * bit is already set, and the woken waiter is expected to deal with
+ * this.
*/
- if (pending_op && !pi && !uval) {
+ owner = uval & FUTEX_TID_MASK;
+
+ if (pending_op && !pi && !owner) {
futex_wake(uaddr, 1, 1, FUTEX_BITSET_MATCH_ANY);
return 0;
}
- if ((uval & FUTEX_TID_MASK) != task_pid_vnr(curr))
+ if (owner != task_pid_vnr(curr))
return 0;
/*
--
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