From: Manfred Spraul <manfred@colorfullife.com>
Independent from the other patches:
undo operations should not result in out of range semaphore values. The test
for newval > SEMVMX is missing. The attached patch adds the test and a
comment.
Signed-Off-By: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/ipc/sem.c | 17 ++++++++++++++++-
1 files changed, 16 insertions(+), 1 deletion(-)
diff -puN ipc/sem.c~ipc-3-3-enforce-semvmx-limit-for-undo ipc/sem.c
--- 25/ipc/sem.c~ipc-3-3-enforce-semvmx-limit-for-undo 2004-07-03 13:09:20.804207792 -0700
+++ 25-akpm/ipc/sem.c 2004-07-03 13:09:20.808207184 -0700
@@ -1286,8 +1286,23 @@ found:
struct sem * sem = &sma->sem_base[i];
if (u->semadj[i]) {
sem->semval += u->semadj[i];
+ /*
+ * Range checks of the new semaphore value,
+ * not defined by sus:
+ * - Some unices ignore the undo entirely
+ * (e.g. HP UX 11i 11.22, Tru64 V5.1)
+ * - some cap the value (e.g. FreeBSD caps
+ * at 0, but doesn't enforce SEMVMX)
+ *
+ * Linux caps the semaphore value, both at 0
+ * and at SEMVMX.
+ *
+ * Manfred <manfred@colorfullife.com>
+ */
if (sem->semval < 0)
- sem->semval = 0; /* shouldn't happen */
+ sem->semval = 0;
+ if (sem->semval > SEMVMX)
+ sem->semval = SEMVMX;
sem->sempid = current->tgid;
}
}
_