Bug 62071

Summary:	ipc/sem.c: sem_otime not updated after wait-for-zero semops that do not wait
Product:	Other	Reporter:	Manfred Spraul (manfred)
Component:	Other	Assignee:	other_other
Status:	RESOLVED CODE_FIX
Severity:	normal
Priority:	P1
Hardware:	All
OS:	Linux
URL:	http://marc.info/?l=linux-kernel&m=137981594522009
Kernel Version:		Subsystem:
Regression:	Yes	Bisected commit-id:
Bug Depends on:
Bug Blocks:	62061

Description Manfred Spraul 2013-09-25 07:56:47 UTC

All successful semop calls must update sem_otime.

Jia noticed that wait-for-zero semops do not update sem_otime if they do not sleep.

Affected:
The bug is present in 3.2.51 - probably all kernels after the introduction of do_smart_update().

Two approaches for fixing:
- Move sem_otime = get_seconds() into perform_atomic_semop and then remove the whole "semop_completed" logic.

OR

- add "if (!alter) sem_otime = get_seconds()" into semtimedop()

Comment 1 Manfred Spraul 2013-10-02 07:18:01 UTC

Fixed

0e8c665699e953fa58dc1b0b0d09e5dce7343cc7 ipc/sem.c: update sem_otime for all operations