Messages in this thread | | | Date | Fri, 26 Feb 2016 14:15:51 -0800 | From | Davidlohr Bueso <> | Subject | Re: [PATCH] Don't set sempid in semctl syscall. |
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On Fri, 26 Feb 2016, Manfred Spraul wrote:
This is a user-visible change, adding mtk.
>Hi, > >On 02/26/2016 01:21 PM, PrasannaKumar Muralidharan wrote: >>From: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> >> >>As described in bug #112271 (bugzilla.kernel.org/show_bug.cgi?id=112271) >>don't set sempid in semctl syscall. Set sempid only when semop is called. >I disagree with the bug report:
This bug report really lacks any kind of motivation for this patch, not posix-friendly is pretty bogus. Albeit we are doing some false publicity.
> >sempid is (and always was on Linux) the pid of the last task that modified the semaphore: >It is updated for semop, SETVAL and undo adjustment on process exit. >And - that is a bug: sempid is not updated for SETALL :-(
Code-wise yeah, but we have such things in our docs (semctl.2):
GETPID Return the value of sempid for the semnum-th semaphore of the set (i.e., the PID of the process that executed the last semop(2) call for the semnum-th semaphore of the set). The calling process must have read permission on the semaphore set.
Furthermore, semop.2 is very explicit about sempid. That said, I am also weary of this change because we've been setting semval for semctl for so long. stuff).
Thanks, Davidlohr
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