From: Vasily Averin vvs@virtuozzo.com
[ Upstream commit 89163f93c6f969da5811af5377cc10173583123b ]
If seq_file .next function does not change position index, read after some lseek can generate unexpected output.
https://bugzilla.kernel.org/show_bug.cgi?id=206283 Signed-off-by: Vasily Averin vvs@virtuozzo.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Acked-by: Waiman Long longman@redhat.com Cc: Davidlohr Bueso dave@stgolabs.net Cc: Manfred Spraul manfred@colorfullife.com Cc: Al Viro viro@zeniv.linux.org.uk Cc: Ingo Molnar mingo@redhat.com Cc: NeilBrown neilb@suse.com Cc: Peter Oberparleiter oberpar@linux.ibm.com Cc: Steven Rostedt rostedt@goodmis.org Link: http://lkml.kernel.org/r/b7a20945-e315-8bb0-21e6-3875c14a8494@virtuozzo.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- ipc/util.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/ipc/util.c b/ipc/util.c index 0f401d94b7c65..2724f9071ab39 100644 --- a/ipc/util.c +++ b/ipc/util.c @@ -756,13 +756,13 @@ static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, total++; }
+ *new_pos = pos + 1; if (total >= ids->in_use) return NULL;
for (; pos < IPCMNI; pos++) { ipc = idr_find(&ids->ipcs_idr, pos); if (ipc != NULL) { - *new_pos = pos + 1; rcu_read_lock(); ipc_lock_object(ipc); return ipc;