Subject: + ipc-semc-synchronize-the-proc-interface.patch added to -mm tree To: manfred@xxxxxxxxxxxxxxxx,davidlohr.bueso@xxxxxx,efault@xxxxxx,riel@xxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Wed, 25 Sep 2013 12:48:32 -0700 The patch titled Subject: ipc/sem.c: synchronize the proc interface has been added to the -mm tree. Its filename is ipc-semc-synchronize-the-proc-interface.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/ipc-semc-synchronize-the-proc-interface.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/ipc-semc-synchronize-the-proc-interface.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx> Subject: ipc/sem.c: synchronize the proc interface The proc interface is not aware of sem_lock(), it calls ipc_lock_object() directly. This means that simple semop() operations can run in parallel with the proc interface. Right now, this is uncritical, because the implementation doesn't do anything that requires a proper synchronization. But it is dangerous and therefore should be fixed. Signed-off-by: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx> Cc: Davidlohr Bueso <davidlohr.bueso@xxxxxx> Cc: Mike Galbraith <efault@xxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- ipc/sem.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff -puN ipc/sem.c~ipc-semc-synchronize-the-proc-interface ipc/sem.c --- a/ipc/sem.c~ipc-semc-synchronize-the-proc-interface +++ a/ipc/sem.c @@ -2103,6 +2103,14 @@ static int sysvipc_sem_proc_show(struct struct sem_array *sma = it; time_t sem_otime; + /* + * The proc interface isn't aware of sem_lock(), it calls + * ipc_lock_object() directly (in sysvipc_find_ipc). + * In order to stay compatible with sem_lock(), we must wait until + * all simple semop() calls have left their critical regions. + */ + sem_wait_array(sma); + sem_otime = get_semotime(sma); return seq_printf(s, _ Patches currently in -mm which might be from manfred@xxxxxxxxxxxxxxxx are origin.patch ipc-semc-fix-race-in-sem_lock.patch ipc-semc-optimize-sem_lock.patch ipc-semc-synchronize-the-proc-interface.patch slab-leaks3-default-y.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html