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charset="us-ascii" Content-ID: <7A339F646F263041BA921D1E210BCD61@eurprd04.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: VI1PR04MB5136.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: d59683e9-4122-480e-2587-08da34bd5537 X-MS-Exchange-CrossTenant-originalarrivaltime: 13 May 2022 08:48:20.8862 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: JKfJGMEy6MD9iV5MZJNIfZ9sYde4a7qM0bAkYItu0FXE030A3/RHA69J/K/2gPJkSPMZRzGdLfftfKRCIO/6Qg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM0PR04MB5636 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, May 13, 2022 at 09:51:34AM +0800, Hangbin Liu wrote: > Remove bpf guys from cc list. >=20 > On Thu, May 12, 2022 at 12:35:28PM -0700, syzbot wrote: > >=20 > > The issue was bisected to: > >=20 > > commit aa6034678e873db8bd5c5a4b73f8b88c469374d6 > > Author: Hangbin Liu > > Date: Fri Jan 21 08:25:18 2022 +0000 > >=20 > > bonding: use rcu_dereference_rtnl when get bonding active slave > >=20 > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=3D16fce349= f00000 > > final oops: https://syzkaller.appspot.com/x/report.txt?x=3D15fce349= f00000 > > console output: https://syzkaller.appspot.com/x/log.txt?x=3D11fce349f00= 000 > >=20 > > IMPORTANT: if you fix the issue, please add the following tag to the co= mmit: > > Reported-by: syzbot+92beb3d46aab498710fa@syzkaller.appspotmail.com > > Fixes: aa6034678e87 ("bonding: use rcu_dereference_rtnl when get bondin= g active slave") > >=20 > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D > > WARNING: suspicious RCU usage > > 5.18.0-rc5-syzkaller-01392-g01f4685797a5 #0 Not tainted > > ----------------------------- > > include/net/bonding.h:353 suspicious rcu_dereference_check() usage! > >=20 > > other info that might help us debug this: > >=20 > >=20 > > rcu_scheduler_active =3D 2, debug_locks =3D 1 > > 1 lock held by syz-executor317/3599: > > #0: ffff88801de78130 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock incl= ude/net/sock.h:1680 [inline] > > #0: ffff88801de78130 (sk_lock-AF_INET){+.+.}-{0:0}, at: sock_setsockop= t+0x1e3/0x2ec0 net/core/sock.c:1066 > >=20 > > stack backtrace: > > CPU: 0 PID: 3599 Comm: syz-executor317 Not tainted 5.18.0-rc5-syzkaller= -01392-g01f4685797a5 #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS= Google 01/01/2011 > > Call Trace: > > > > __dump_stack lib/dump_stack.c:88 [inline] > > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 > > bond_option_active_slave_get_rcu include/net/bonding.h:353 [inline] > > bond_ethtool_get_ts_info+0x32c/0x3a0 drivers/net/bonding/bond_main.c:5= 595 > > __ethtool_get_ts_info+0x173/0x240 net/ethtool/common.c:554 > > ethtool_get_phc_vclocks+0x99/0x110 net/ethtool/common.c:568 > > sock_timestamping_bind_phc net/core/sock.c:869 [inline] > > sock_set_timestamping+0x3a3/0x7e0 net/core/sock.c:916 > > sock_setsockopt+0x543/0x2ec0 net/core/sock.c:1221 >=20 > Oh, I forgot to check setsockopt path... >=20 > Hi Vladimir, Jay, >=20 > Do you think if I should revert my previous commit, or just add > rcu_read_lock()/rcu_read_unlock() back to bond_ethtool_get_ts_info()? >=20 > Thanks > Hangbin Hi Hangbin, sock_timestamping_bind_phc() appears to run unlocked, with the exception of the rcu_read_lock() in dev_get_by_index() in which there is a dev_hold()= . I'm thinking that this dev_hold ensures that the bonding interface does not go away, but it still does not ensure that the active slave does not go away. I only looked superficially at this because I am AFK today, but I think I would put rcu_read_lock() in bond_ethtool_get_ts_info(), but not the way in which it was before, but rather for the entire time during which real_dev, ops and phydev are being dereferenced.=