MFC r266782:

In r218101 I have not changed properly the futex syscall definition.
Some Linux futex ops atomically verifies that the futex address uaddr
(uval) contains the value val. Comparing signed uval and unsigned val
may lead to an unexpected result, mostly to a deadlock.

So copyin uaddr to an unsigned int to compare the parameters correctly.

While here change ktr records to print parameters in more readable format.

1 files changed, 16 insertions, 13 deletions

diff --git a/sys/compat/linux/linux_futex.c b/sys/compat/linux/linux_futex.c
index 9b4c92f..be8286a 100644
--- a/sys/compat/linux/linux_futex.c
+++ b/sys/compat/linux/linux_futex.c
@@ -680,12 +680,12 @@ futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr)
 int
 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 {
-	int clockrt, nrwake, op_ret, ret, val;
+	int clockrt, nrwake, op_ret, ret;
 	struct linux_emuldata *em;
 	struct waiting_proc *wp;
 	struct futex *f, *f2;
 	int error;
-	uint32_t flags;
+	uint32_t flags, val;
 
 	LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args);
 
@@ -722,7 +722,7 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 	case LINUX_FUTEX_WAIT_BITSET:
 		LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr,
 		    args->val, args->val3);
-		LINUX_CTR3(sys_futex, "WAIT uaddr %p val %d val3 %d",
+		LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x",
 		    args->uaddr, args->val, args->val3);
 
 		error = futex_get(args->uaddr, &wp, &f,
@@ -747,9 +747,9 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 			LIN_SDT_PROBE4(futex, linux_sys_futex,
 			    debug_wait_value_neq, args->uaddr, args->val, val,
 			    args->val3);
-			LINUX_CTR4(sys_futex,
-			    "WAIT uaddr %p val %d != uval %d val3 %d",
-			    args->uaddr, args->val, val, args->val3);
+			LINUX_CTR3(sys_futex,
+			    "WAIT uaddr %p val 0x%x != uval 0x%x",
+			    args->uaddr, args->val, val);
 			futex_put(f, wp);
 
 			LIN_SDT_PROBE1(futex, linux_sys_futex, return,
@@ -767,7 +767,7 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 	case LINUX_FUTEX_WAKE_BITSET:
 		LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr,
 		    args->val, args->val3);
-		LINUX_CTR3(sys_futex, "WAKE uaddr %p val % d val3 %d",
+		LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x",
 		    args->uaddr, args->val, args->val3);
 
 		error = futex_get(args->uaddr, NULL, &f,
@@ -792,9 +792,9 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 		    args->uaddr, args->val, args->val3, args->uaddr2,
 		    args->timeout);
 		LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p "
-		    "val %d val3 %d uaddr2 %p val2 %d",
+		    "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x",
 		    args->uaddr, args->val, args->val3, args->uaddr2,
-		    (int)(unsigned long)args->timeout);
+		    args->timeout);
 
 		/*
 		 * Linux allows this, we would not, it is an incorrect
@@ -843,7 +843,7 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 		if (val != args->val3) {
 			LIN_SDT_PROBE2(futex, linux_sys_futex,
 			    debug_cmp_requeue_value_neq, args->val, val);
-			LINUX_CTR2(sys_futex, "CMP_REQUEUE val %d != uval %d",
+			LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x",
 			    args->val, val);
 			futex_put(f2, NULL);
 			futex_put(f, NULL);
@@ -862,9 +862,9 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 		LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op,
 		    args->uaddr, args->op, args->val, args->uaddr2, args->val3);
 		LINUX_CTR5(sys_futex, "WAKE_OP "
-		    "uaddr %p op %d val %x uaddr2 %p val3 %x",
-		    args->uaddr, args->op, args->val,
-		    args->uaddr2, args->val3);
+		    "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x",
+		    args->uaddr, args->val, args->uaddr2, args->val3,
+		    args->timeout);
 
 		error = futex_get(args->uaddr, NULL, &f, flags);
 		if (error) {
@@ -887,6 +887,9 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 		 */
 		op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
 
+		LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x",
+		    args->uaddr, op_ret);
+
 		if (op_ret < 0) {
 			/* XXX: We don't handle the EFAULT yet. */
 			if (op_ret != -EFAULT) {