Messages in this thread | | | From | Hawkins Jiawei <> | Date | Thu, 1 Dec 2022 21:20:51 +0800 | Subject | Re: [PATCH v3] net: sched: fix memory leak in tcindex_set_parms |
| |
On Thu, 1 Dec 2022 at 18:24, Paolo Abeni <pabeni@redhat.com> wrote: > > On Tue, 2022-11-29 at 10:52 +0800, Hawkins Jiawei wrote: > > Syzkaller reports a memory leak as follows: > > ==================================== > > BUG: memory leak > > unreferenced object 0xffff88810c287f00 (size 256): > > comm "syz-executor105", pid 3600, jiffies 4294943292 (age 12.990s) > > hex dump (first 32 bytes): > > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > > backtrace: > > [<ffffffff814cf9f0>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046 > > [<ffffffff839c9e07>] kmalloc include/linux/slab.h:576 [inline] > > [<ffffffff839c9e07>] kmalloc_array include/linux/slab.h:627 [inline] > > [<ffffffff839c9e07>] kcalloc include/linux/slab.h:659 [inline] > > [<ffffffff839c9e07>] tcf_exts_init include/net/pkt_cls.h:250 [inline] > > [<ffffffff839c9e07>] tcindex_set_parms+0xa7/0xbe0 net/sched/cls_tcindex.c:342 > > [<ffffffff839caa1f>] tcindex_change+0xdf/0x120 net/sched/cls_tcindex.c:553 > > [<ffffffff8394db62>] tc_new_tfilter+0x4f2/0x1100 net/sched/cls_api.c:2147 > > [<ffffffff8389e91c>] rtnetlink_rcv_msg+0x4dc/0x5d0 net/core/rtnetlink.c:6082 > > [<ffffffff839eba67>] netlink_rcv_skb+0x87/0x1d0 net/netlink/af_netlink.c:2540 > > [<ffffffff839eab87>] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] > > [<ffffffff839eab87>] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345 > > [<ffffffff839eb046>] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921 > > [<ffffffff8383e796>] sock_sendmsg_nosec net/socket.c:714 [inline] > > [<ffffffff8383e796>] sock_sendmsg+0x56/0x80 net/socket.c:734 > > [<ffffffff8383eb08>] ____sys_sendmsg+0x178/0x410 net/socket.c:2482 > > [<ffffffff83843678>] ___sys_sendmsg+0xa8/0x110 net/socket.c:2536 > > [<ffffffff838439c5>] __sys_sendmmsg+0x105/0x330 net/socket.c:2622 > > [<ffffffff83843c14>] __do_sys_sendmmsg net/socket.c:2651 [inline] > > [<ffffffff83843c14>] __se_sys_sendmmsg net/socket.c:2648 [inline] > > [<ffffffff83843c14>] __x64_sys_sendmmsg+0x24/0x30 net/socket.c:2648 > > [<ffffffff84605fd5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > [<ffffffff84605fd5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > > [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd > > ==================================== > > > > Kernel uses tcindex_change() to change an existing > > filter properties. During the process of changing, > > kernel uses tcindex_alloc_perfect_hash() to newly > > allocate filter results, uses tcindex_filter_result_init() > > to clear the old filter result. > > > > Yet the problem is that, kernel clears the old > > filter result, without destroying its tcf_exts structure, > > which triggers the above memory leak. > > > > Considering that there already extis a tc_filter_wq workqueue > > to destroy the old tcindex_data by tcindex_partial_destroy_work() > > at the end of tcindex_set_parms(), this patch solves this memory > > leak bug by removing this old filter result clearing part, > > and delegating it to the tc_filter_wq workqueue. > > > > [Thanks to the suggestion from Jakub Kicinski, Cong Wang, Paolo Abeni > > and Dmitry Vyukov] > > > > Fixes: b9a24bb76bf6 ("net_sched: properly handle failure case of tcf_exts_init()") > > Link: https://lore.kernel.org/all/0000000000001de5c505ebc9ec59@google.com/ > > Reported-by: syzbot+232ebdbd36706c965ebf@syzkaller.appspotmail.com > > Tested-by: syzbot+232ebdbd36706c965ebf@syzkaller.appspotmail.com > > Cc: Cong Wang <cong.wang@bytedance.com> > > Cc: Jakub Kicinski <kuba@kernel.org> > > Cc: Paolo Abeni <pabeni@redhat.com> > > Cc: Dmitry Vyukov <dvyukov@google.com> > > Signed-off-by: Hawkins Jiawei <yin31149@gmail.com> > > The patch looks correct to me, but we are very late in this release > cycle, and I fear there is a chance of introducing some regression. The > issue addressed here is present since quite some time, I suggest to > postpone this fix to the beginning of the next release cycle. > > Please, repost this patch after that 6.1 is released, thanks! (And feel > free to add my Acked-by).
Thanks for your review.
I will retest this patch after 6.1, and repost this patch if the patch works fine.
> > Paolo >
| |