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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Mikhail Ulyanov , Sergei Shtylyov Cc: Thomas Petazzoni , =?UTF-8?Q?Niklas_S=C3=B6derlund?= , Claudiu Beznea , netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250122-fix_missing_rtnl_lock_phy_disconnect-v1-0-8cb9f6f88fd1@bootlin.com> <20250122-fix_missing_rtnl_lock_phy_disconnect-v1-1-8cb9f6f88fd1@bootlin.com> From: Claudiu Beznea Content-Language: en-US In-Reply-To: <20250122-fix_missing_rtnl_lock_phy_disconnect-v1-1-8cb9f6f88fd1@bootlin.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi, Kory, On 22.01.2025 18:19, Kory Maincent wrote: > Fix the suspend path by ensuring the rtnl lock is held where required. > Calls to ravb_open, ravb_close and wol operations must be performed under > the rtnl lock to prevent conflicts with ongoing ndo operations. > > Without this fix, the following warning is triggered: > [ 39.032969] ============================= > [ 39.032983] WARNING: suspicious RCU usage > [ 39.033019] ----------------------------- > [ 39.033033] drivers/net/phy/phy_device.c:2004 suspicious > rcu_dereference_protected() usage! > ... > [ 39.033597] stack backtrace: > [ 39.033613] CPU: 0 UID: 0 PID: 174 Comm: python3 Not tainted > 6.13.0-rc7-next-20250116-arm64-renesas-00002-g35245dfdc62c #7 > [ 39.033623] Hardware name: Renesas SMARC EVK version 2 based on > r9a08g045s33 (DT) > [ 39.033628] Call trace: > [ 39.033633] show_stack+0x14/0x1c (C) > [ 39.033652] dump_stack_lvl+0xb4/0xc4 > [ 39.033664] dump_stack+0x14/0x1c > [ 39.033671] lockdep_rcu_suspicious+0x16c/0x22c > [ 39.033682] phy_detach+0x160/0x190 > [ 39.033694] phy_disconnect+0x40/0x54 > [ 39.033703] ravb_close+0x6c/0x1cc > [ 39.033714] ravb_suspend+0x48/0x120 > [ 39.033721] dpm_run_callback+0x4c/0x14c > [ 39.033731] device_suspend+0x11c/0x4dc > [ 39.033740] dpm_suspend+0xdc/0x214 > [ 39.033748] dpm_suspend_start+0x48/0x60 > [ 39.033758] suspend_devices_and_enter+0x124/0x574 > [ 39.033769] pm_suspend+0x1ac/0x274 > [ 39.033778] state_store+0x88/0x124 > [ 39.033788] kobj_attr_store+0x14/0x24 > [ 39.033798] sysfs_kf_write+0x48/0x6c > [ 39.033808] kernfs_fop_write_iter+0x118/0x1a8 > [ 39.033817] vfs_write+0x27c/0x378 > [ 39.033825] ksys_write+0x64/0xf4 > [ 39.033833] __arm64_sys_write+0x18/0x20 > [ 39.033841] invoke_syscall+0x44/0x104 > [ 39.033852] el0_svc_common.constprop.0+0xb4/0xd4 > [ 39.033862] do_el0_svc+0x18/0x20 > [ 39.033870] el0_svc+0x3c/0xf0 > [ 39.033880] el0t_64_sync_handler+0xc0/0xc4 > [ 39.033888] el0t_64_sync+0x154/0x158 > [ 39.041274] ravb 11c30000.ethernet eth0: Link is Down > > Reported-by: Claudiu Beznea > Closes: https://lore.kernel.org/netdev/4c6419d8-c06b-495c-b987-d66c2e1ff848@tuxon.dev/ > Fixes: 0184165b2f42 ("ravb: add sleep PM suspend/resume support") > Signed-off-by: Kory Maincent I've test it. Looks good. Thank you for your patch. However, I think this could be simplified. The locking scheme looks complicated to me. E.g., this one works too: diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index bc395294a32d..cfe4f0f364f3 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c @@ -3217,10 +3217,16 @@ static int ravb_suspend(struct device *dev) netif_device_detach(ndev); - if (priv->wol_enabled) - return ravb_wol_setup(ndev); + if (priv->wol_enabled) { + rtnl_lock(); + ret = ravb_wol_setup(ndev); + rtnl_unlock(); + return ret; + } + rtnl_lock(); ret = ravb_close(ndev); + rtnl_unlock(); if (ret) return ret; @@ -3247,7 +3253,9 @@ static int ravb_resume(struct device *dev) /* If WoL is enabled restore the interface. */ if (priv->wol_enabled) { + rtnl_lock(); ret = ravb_wol_restore(ndev); + rtnl_unlock(); if (ret) return ret; } else { @@ -3257,7 +3265,9 @@ static int ravb_resume(struct device *dev) } /* Reopening the interface will restore the device to the working state. */ + rtnl_lock(); ret = ravb_open(ndev); + rtnl_unlock(); if (ret < 0) goto out_rpm_put; > --- > drivers/net/ethernet/renesas/ravb_main.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c > index bc395294a32d..2c6d8e4966c3 100644 > --- a/drivers/net/ethernet/renesas/ravb_main.c > +++ b/drivers/net/ethernet/renesas/ravb_main.c > @@ -3217,10 +3217,15 @@ static int ravb_suspend(struct device *dev) > > netif_device_detach(ndev); > > - if (priv->wol_enabled) > - return ravb_wol_setup(ndev); > + rtnl_lock(); > + if (priv->wol_enabled) { > + ret = ravb_wol_setup(ndev); > + rtnl_unlock(); > + return ret; > + } > > ret = ravb_close(ndev); > + rtnl_unlock(); > if (ret) > return ret; > > @@ -3245,19 +3250,25 @@ static int ravb_resume(struct device *dev) > if (!netif_running(ndev)) > return 0; > > + rtnl_lock(); > /* If WoL is enabled restore the interface. */ > if (priv->wol_enabled) { > ret = ravb_wol_restore(ndev); > - if (ret) > + if (ret) { > + rtnl_unlock(); > return ret; > + } > } else { > ret = pm_runtime_force_resume(dev); > - if (ret) > + if (ret) { > + rtnl_unlock(); > return ret; > + } > } > > /* Reopening the interface will restore the device to the working state. */ > ret = ravb_open(ndev); > + rtnl_unlock(); > if (ret < 0) > goto out_rpm_put; > >