From: Hoang Le hoang.h.le@dektech.com.au
[ Upstream commit 911600bf5a5e84bfda4d33ee32acc75ecf6159f0 ]
syzbot found the following issue on: ================================================================== BUG: KASAN: use-after-free in tipc_named_reinit+0x94f/0x9b0 net/tipc/name_distr.c:413 Read of size 8 at addr ffff88805299a000 by task kworker/1:9/23764
CPU: 1 PID: 23764 Comm: kworker/1:9 Not tainted 5.18.0-rc4-syzkaller-00878-g17d49e6e8012 #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events tipc_net_finalize_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313 print_report mm/kasan/report.c:429 [inline] kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491 tipc_named_reinit+0x94f/0x9b0 net/tipc/name_distr.c:413 tipc_net_finalize+0x234/0x3d0 net/tipc/net.c:138 process_one_work+0x996/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 </TASK> [...] ==================================================================
In the commit d966ddcc3821 ("tipc: fix a deadlock when flushing scheduled work"), the cancel_work_sync() function just to make sure ONLY the work tipc_net_finalize_work() is executing/pending on any CPU completed before tipc namespace is destroyed through tipc_exit_net(). But this function is not guaranteed the work is the last queued. So, the destroyed instance may be accessed in the work which will try to enqueue later.
In order to completely fix, we re-order the calling of cancel_work_sync() to make sure the work tipc_net_finalize_work() was last queued and it must be completed by calling cancel_work_sync().
Reported-by: syzbot+47af19f3307fc9c5c82e@syzkaller.appspotmail.com Fixes: d966ddcc3821 ("tipc: fix a deadlock when flushing scheduled work") Acked-by: Jon Maloy jmaloy@redhat.com Signed-off-by: Ying Xue ying.xue@windriver.com Signed-off-by: Hoang Le hoang.h.le@dektech.com.au Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/tipc/core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/net/tipc/core.c b/net/tipc/core.c index 96bfcb2986f5..7724499f516e 100644 --- a/net/tipc/core.c +++ b/net/tipc/core.c @@ -111,10 +111,9 @@ static void __net_exit tipc_exit_net(struct net *net) struct tipc_net *tn = tipc_net(net);
tipc_detach_loopback(net); + tipc_net_stop(net); /* Make sure the tipc_net_finalize_work() finished */ cancel_work_sync(&tn->work); - tipc_net_stop(net); - tipc_bcast_stop(net); tipc_nametbl_stop(net); tipc_sk_rht_destroy(net);