On Fri, Aug 26, 2016 at 8:25 AM, CAI Qian <caiq...@redhat.com> wrote: > > > ----- Original Message ----- >> From: "Linus Torvalds" <torva...@linux-foundation.org> >> To: "CAI Qian" <caiq...@redhat.com>, "Thomas Graf" <tg...@suug.ch>, "Herbert >> Xu" <herb...@gondor.apana.org.au> >> Cc: "Eric Dumazet" <eduma...@google.com>, "Network Development" >> <netdev@vger.kernel.org> >> Sent: Thursday, August 25, 2016 6:20:03 PM >> Subject: Re: possible memory leak in ipc >> >> On Thu, Aug 25, 2016 at 1:17 PM, CAI Qian <caiq...@redhat.com> wrote: >> > I am unsure if it is really a memleak (could be a security issue due to >> > eventually OOM and DoS) or just a soft lockup with in kmemlock code with >> > false alarm. >> >> Hmm. The reported leaks look like >> >> unreferenced object 0xffffc90004857000 (size 4608): >> comm "kworker/16:0", pid 110, jiffies 4294705908 (age 883.925s) >> hex dump (first 32 bytes): >> c0 05 3d 5e 08 88 ff ff ff ff ff ff 00 00 dc 6e ..=^...........n >> ff ff ff ff ff ff ff ff 28 c7 46 83 ff ff ff ff ........(.F..... >> backtrace: >> [<ffffffff817d95ba>] kmemleak_alloc+0x4a/0xa0 >> [<ffffffff8123df4e>] __vmalloc_node_range+0x1de/0x2f0 >> [<ffffffff8123e324>] vmalloc+0x54/0x60 >> [<ffffffff81404934>] alloc_bucket_locks.isra.7+0xd4/0xf0 >> [<ffffffff814049a8>] bucket_table_alloc+0x58/0x100 >> [<ffffffff8140538e>] rht_deferred_worker+0x10e/0x890 >> [<ffffffff810c30a8>] process_one_work+0x218/0x750 >> [<ffffffff810c3705>] worker_thread+0x125/0x4a0 >> [<ffffffff810ca8b1>] kthread+0x101/0x120 >> [<ffffffff817e70af>] ret_from_fork+0x1f/0x40 >> [<ffffffffffffffff>] 0xffffffffffffffff >> >> which would indicate that it's a rhashtable resize event where we >> perhaps haven't free'd the old hash table when we create a new one. >> >> The actually freeing of the old one is done RCU-deferred from >> rhashtable_rehash_table(), but that itself is also deferred by a >> worker thread (rht_deferred_worker). >> >> I'm not seeing anything wrong in the logic, but let's bring in Thomas >> Graf and Herbert Xu. >
There is a trivial bug in alloc_bucket_locks() I will send a patch. Thanks.
