This is a note to let you know that I've just added the patch titled
ipc/sem.c: synchronize the proc interface
to the 3.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ipc-sem.c-synchronize-the-proc-interface.patch
and it can be found in the queue-3.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d8c633766ad88527f25d9f81a5c2f083d78a2b39 Mon Sep 17 00:00:00 2001
From: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Date: Mon, 30 Sep 2013 13:45:07 -0700
Subject: ipc/sem.c: synchronize the proc interface
From: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
commit d8c633766ad88527f25d9f81a5c2f083d78a2b39 upstream.
The proc interface is not aware of sem_lock(), it instead 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>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
ipc/sem.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/ipc/sem.c
+++ b/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 stable-queue which might be from manfred@xxxxxxxxxxxxxxxx are
queue-3.11/ipc-drop-ipc_lock_by_ptr.patch
queue-3.11/ipc-sem.c-synchronize-the-proc-interface.patch
queue-3.11/ipc-msg-drop-msg_unlock.patch
queue-3.11/ipc-shm-shorten-critical-region-in-shmctl_down.patch
queue-3.11/ipc-rename-ids-rw_mutex.patch
queue-3.11/ipc-shm-introduce-lockless-functions-to-obtain-the-ipc-object.patch
queue-3.11/ipc-sem.c-optimize-sem_lock.patch
queue-3.11/ipc-shm-shorten-critical-region-for-shmat.patch
queue-3.11/ipc-shm-shorten-critical-region-for-shmctl.patch
queue-3.11/ipc-shm-introduce-shmctl_nolock.patch
queue-3.11/ipc-drop-ipcctl_pre_down.patch
queue-3.11/ipc-document-general-ipc-locking-scheme.patch
queue-3.11/ipc-shm-drop-shm_lock_check.patch
queue-3.11/ipc-shm-guard-against-non-existant-vma-in-shmdt-2.patch
queue-3.11/ipc-shm-cleanup-do_shmat-pasta.patch
queue-3.11/ipc-drop-ipc_lock_check.patch
queue-3.11/ipc-sem.c-update-sem_otime-for-all-operations.patch
queue-3.11/ipc-shm-make-shmctl_nolock-lockless.patch
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