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
