forked from ~ljy/RK356X_SDK_RELEASE

blame | history | patch | commit | commitdiff
hc
2024-01-03 2f7c68cb55ecb7331f2381deb497c27155f32faf 
 kernel/kernel/futex.c
similarity index 98%rename from kernel/kernel/futex.crename to kernel/kernel/futex/core.c
....@@ -42,7 +42,7 @@
4242 
4343 #include <asm/futex.h>
4444 
45
-#include "locking/rtmutex_common.h"
45
+#include "../locking/rtmutex_common.h"
4646 #include <trace/hooks/futex.h>
4747 
4848 /*
....@@ -3417,6 +3417,7 @@
34173417 			      bool pi, bool pending_op)
34183418 {
34193419 	u32 uval, nval, mval;
3420
+	pid_t owner;
34203421 	int err;
34213422 
34223423 	/* Futex address must be 32bit aligned */
....@@ -3438,6 +3439,10 @@
34383439 	 * 2. A woken up waiter is killed before it can acquire the
34393440 	 *    futex in user space.
34403441 	 *
3442
+	 * In the second case, the wake up notification could be generated
3443
+	 * by the unlock path in user space after setting the futex value
3444
+	 * to zero or by the kernel after setting the OWNER_DIED bit below.
3445
+	 *
34413446 	 * In both cases the TID validation below prevents a wakeup of
34423447 	 * potential waiters which can cause these waiters to block
34433448 	 * forever.
....@@ -3446,24 +3451,27 @@
34463451 	 *
34473452 	 *	1) task->robust_list->list_op_pending != NULL
34483453 	 *	   @pending_op == true
3449
-	 *	2) User space futex value == 0
3454
+	 *	2) The owner part of user space futex value == 0
34503455 	 *	3) Regular futex: @pi == false
34513456 	 *
34523457 	 * If these conditions are met, it is safe to attempt waking up a
34533458 	 * potential waiter without touching the user space futex value and
3454
-	 * trying to set the OWNER_DIED bit. The user space futex value is
3455
-	 * uncontended and the rest of the user space mutex state is
3456
-	 * consistent, so a woken waiter will just take over the
3457
-	 * uncontended futex. Setting the OWNER_DIED bit would create
3458
-	 * inconsistent state and malfunction of the user space owner died
3459
-	 * handling.
3459
+	 * trying to set the OWNER_DIED bit. If the futex value is zero,
3460
+	 * the rest of the user space mutex state is consistent, so a woken
3461
+	 * waiter will just take over the uncontended futex. Setting the
3462
+	 * OWNER_DIED bit would create inconsistent state and malfunction
3463
+	 * of the user space owner died handling. Otherwise, the OWNER_DIED
3464
+	 * bit is already set, and the woken waiter is expected to deal with
3465
+	 * this.
34603466 	 */
3461
-	if (pending_op && !pi && !uval) {
3467
+	owner = uval & FUTEX_TID_MASK;
3468
+
3469
+	if (pending_op && !pi && !owner) {
34623470 		futex_wake(uaddr, 1, 1, FUTEX_BITSET_MATCH_ANY);
34633471 		return 0;
34643472 	}
34653473 
3466
-	if ((uval & FUTEX_TID_MASK) != task_pid_vnr(curr))
3474
+	if (owner != task_pid_vnr(curr))
34673475 		return 0;
34683476 
34693477 	/*