Hi Lee, On Tue, Jun 21, 2022 at 11:35 AM Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx> wrote: > > Hi Lee, > > On Tue, Jun 21, 2022 at 7:38 AM Lee Jones <lee.jones@xxxxxxxxxx> wrote: > > > > On Tue, 07 Jun 2022, Lee Jones wrote: > > > > > This change prevents a use-after-free caused by one of the worker > > > threads starting up (see below) *after* the final channel reference > > > has been put() during sock_close() but *before* the references to the > > > channel have been destroyed. > > > > > > refcount_t: increment on 0; use-after-free. > > > BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0 > > > Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705 > > > > > > CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S W 4.14.234-00003-g1fb6d0bd49a4-dirty #28 > > > Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Flame DVT (DT) > > > Workqueue: hci0 hci_rx_work > > > Call trace: > > > dump_backtrace+0x0/0x378 > > > show_stack+0x20/0x2c > > > dump_stack+0x124/0x148 > > > print_address_description+0x80/0x2e8 > > > __kasan_report+0x168/0x188 > > > kasan_report+0x10/0x18 > > > __asan_load4+0x84/0x8c > > > refcount_dec_and_test+0x20/0xd0 > > > l2cap_chan_put+0x48/0x12c > > > l2cap_recv_frame+0x4770/0x6550 > > > l2cap_recv_acldata+0x44c/0x7a4 > > > hci_acldata_packet+0x100/0x188 > > > hci_rx_work+0x178/0x23c > > > process_one_work+0x35c/0x95c > > > worker_thread+0x4cc/0x960 > > > kthread+0x1a8/0x1c4 > > > ret_from_fork+0x10/0x18 > > > > > > Cc: stable@xxxxxxxxxx > > > Cc: Marcel Holtmann <marcel@xxxxxxxxxxxx> > > > Cc: Johan Hedberg <johan.hedberg@xxxxxxxxx> > > > Cc: Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx> > > > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> > > > Cc: Eric Dumazet <edumazet@xxxxxxxxxx> > > > Cc: Jakub Kicinski <kuba@xxxxxxxxxx> > > > Cc: Paolo Abeni <pabeni@xxxxxxxxxx> > > > Cc: linux-bluetooth@xxxxxxxxxxxxxxx > > > Cc: netdev@xxxxxxxxxxxxxxx > > > Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx> > > > --- > > > net/bluetooth/l2cap_core.c | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > No reply for 2 weeks. > > > > Is this patch being considered at all? > > > > Can I help in any way? > > Could you please resend to trigger CI, looks like CI missed this one > for some reason. Btw, it would be great to have a test for this sort of fix so CI reproduce and thus we avoid reintroducing it: https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/tools/l2cap-tester.c > > > > > > diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c > > > index ae78490ecd3d4..82279c5919fd8 100644 > > > --- a/net/bluetooth/l2cap_core.c > > > +++ b/net/bluetooth/l2cap_core.c > > > @@ -483,9 +483,7 @@ static void l2cap_chan_destroy(struct kref *kref) > > > > > > BT_DBG("chan %p", chan); > > > > > > - write_lock(&chan_list_lock); > > > list_del(&chan->global_l); > > > - write_unlock(&chan_list_lock); > > > > > > kfree(chan); > > > } > > > @@ -501,7 +499,9 @@ void l2cap_chan_put(struct l2cap_chan *c) > > > { > > > BT_DBG("chan %p orig refcnt %u", c, kref_read(&c->kref)); > > > > > > + write_lock(&chan_list_lock); > > > kref_put(&c->kref, l2cap_chan_destroy); > > > + write_unlock(&chan_list_lock); > > > } > > > EXPORT_SYMBOL_GPL(l2cap_chan_put); > > > > > > > -- > > Lee Jones [李琼斯] > > Principal Technical Lead - Developer Services > > Linaro.org │ Open source software for Arm SoCs > > Follow Linaro: Facebook | Twitter | Blog > > > > -- > Luiz Augusto von Dentz -- Luiz Augusto von Dentz
