sysv semaphore broken

Maxim Konovalov maxim at macomnet.ru
Thu Jun 29 11:06:41 UTC 2006


On Thu, 29 Jun 2006, 12:48+0400, Maxim Konovalov wrote:

> On Thu, 29 Jun 2006, 15:39+0800, David Xu wrote:
>
> > Is sysv semaphore broken ? all super-smack processes are
> > stucked at "semwai" state now.
>
> There was a report that recent commit broke sysv sems.  Looking at it
> ATM.
>
> [root at fujic /usr/src/tools/regression/sysvsem]# make regress
> semtest: semctl IPC_STAT: Invalid argument
> semtest: semctl IPC_RMID: Invalid argument
> FAIL

Something like that should fix the issue:

Index: sysv_sem.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/sysv_sem.c,v
retrieving revision 1.80
diff -u -p -r1.80 sysv_sem.c
--- sysv_sem.c	27 Jun 2006 18:28:50 -0000	1.80
+++ sysv_sem.c	29 Jun 2006 11:00:43 -0000
@@ -586,7 +586,7 @@ kern_semctl(struct thread *td, int semid
 {
 	u_short *array;
 	struct ucred *cred = td->td_ucred;
-	int i, rval, error;
+	int i, rval, error, savedid;
 	struct semid_ds sbuf;
 	struct semid_kernel *semakptr;
 	struct mtx *sema_mtxp;
@@ -632,6 +632,7 @@ kern_semctl(struct thread *td, int semid
 		return (error);
 	}

+	savedid = semid;
 	semid = IPCID_TO_IX(semid);
 	if (semid < 0 || semid >= seminfo.semmni)
 		return (EINVAL);
@@ -655,7 +656,7 @@ kern_semctl(struct thread *td, int semid
 	switch (cmd) {
 	case IPC_RMID:
 		mtx_lock(sema_mtxp);
-		if ((error = semvalid(semid, semakptr)) != 0)
+		if ((error = semvalid(savedid, semakptr)) != 0)
 			goto done2;
 		if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
 			goto done2;
@@ -687,7 +688,7 @@ kern_semctl(struct thread *td, int semid
 		} else
 			bcopy(arg->buf, &sbuf, sizeof(sbuf));
 		mtx_lock(sema_mtxp);
-		if ((error = semvalid(semid, semakptr)) != 0)
+		if ((error = semvalid(savedid, semakptr)) != 0)
 			goto done2;
 		if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_M)))
 			goto done2;
@@ -700,7 +701,7 @@ kern_semctl(struct thread *td, int semid

 	case IPC_STAT:
 		mtx_lock(sema_mtxp);
-		if ((error = semvalid(semid, semakptr)) != 0)
+		if ((error = semvalid(savedid, semakptr)) != 0)
 			goto done2;
 		if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
 			goto done2;
@@ -715,7 +716,7 @@ kern_semctl(struct thread *td, int semid

 	case GETNCNT:
 		mtx_lock(sema_mtxp);
-		if ((error = semvalid(semid, semakptr)) != 0)
+		if ((error = semvalid(savedid, semakptr)) != 0)
 			goto done2;
 		if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
 			goto done2;
@@ -728,7 +729,7 @@ kern_semctl(struct thread *td, int semid

 	case GETPID:
 		mtx_lock(sema_mtxp);
-		if ((error = semvalid(semid, semakptr)) != 0)
+		if ((error = semvalid(savedid, semakptr)) != 0)
 			goto done2;
 		if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
 			goto done2;
@@ -741,7 +742,7 @@ kern_semctl(struct thread *td, int semid

 	case GETVAL:
 		mtx_lock(sema_mtxp);
-		if ((error = semvalid(semid, semakptr)) != 0)
+		if ((error = semvalid(savedid, semakptr)) != 0)
 			goto done2;
 		if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
 			goto done2;
@@ -764,7 +765,7 @@ kern_semctl(struct thread *td, int semid
 		array = malloc(sizeof(*array) * semakptr->u.sem_nsems, M_TEMP,
 		    M_WAITOK);
 		mtx_lock(sema_mtxp);
-		if ((error = semvalid(semid, semakptr)) != 0)
+		if ((error = semvalid(savedid, semakptr)) != 0)
 			goto done2;
 		if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
 			goto done2;
@@ -777,7 +778,7 @@ kern_semctl(struct thread *td, int semid

 	case GETZCNT:
 		mtx_lock(sema_mtxp);
-		if ((error = semvalid(semid, semakptr)) != 0)
+		if ((error = semvalid(savedid, semakptr)) != 0)
 			goto done2;
 		if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_R)))
 			goto done2;
@@ -790,7 +791,7 @@ kern_semctl(struct thread *td, int semid

 	case SETVAL:
 		mtx_lock(sema_mtxp);
-		if ((error = semvalid(semid, semakptr)) != 0)
+		if ((error = semvalid(savedid, semakptr)) != 0)
 			goto done2;
 		if ((error = ipcperm(td, &semakptr->u.sem_perm, IPC_W)))
 			goto done2;
@@ -819,7 +820,7 @@ kern_semctl(struct thread *td, int semid
 			return (EINVAL);
 		mtx_lock(sema_mtxp);
 raced:
-		if ((error = semvalid(semid, semakptr)) != 0)
+		if ((error = semvalid(savedid, semakptr)) != 0)
 			goto done2;
 		count = semakptr->u.sem_nsems;
 		mtx_unlock(sema_mtxp);
@@ -828,7 +829,7 @@ raced:
 		if (error)
 			break;
 		mtx_lock(sema_mtxp);
-		if ((error = semvalid(semid, semakptr)) != 0)
+		if ((error = semvalid(savedid, semakptr)) != 0)
 			goto done2;
 		/* we could have raced? */
 		if (count != semakptr->u.sem_nsems) {
%%%

-- 
Maxim Konovalov


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