From: Andrew Lunn <andrew@lunn.ch> To: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>, Tony Nguyen <anthony.l.nguyen@intel.com>, "David S. Miller" <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>, Shiraz Saleem <shiraz.saleem@intel.com>, Dave Ertman <david.m.ertman@intel.com>, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org Subject: Re: [PATCH] ice: Don't use GFP_KERNEL in atomic context Date: Sun, 16 Jan 2022 22:42:41 +0100 [thread overview] Message-ID: <YeSRUVmrdmlUXHDn@lunn.ch> (raw) In-Reply-To: <40c94af2f9140794351593047abc95ca65e4e576.1642358759.git.christophe.jaillet@wanadoo.fr> On Sun, Jan 16, 2022 at 07:46:20PM +0100, Christophe JAILLET wrote: > ice_misc_intr() is an irq handler. It should not sleep. > > Use GFP_ATOMIC instead of GFP_KERNEL when allocating some memory. > > Fixes: 348048e724a0 ("ice: Implement iidc operations") > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> > --- > I've never played a lot with irq handler. My understanding is that they > should never sleep. Hi Christophe Threaded interrupt handlers are allowed to sleep. However, this handler is not being used in such a way. So your are probably correct about GFP_KERNEL vs GFP_ATOMIC. > --- > drivers/net/ethernet/intel/ice/ice_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c > index 30814435f779..65de01f3a504 100644 > --- a/drivers/net/ethernet/intel/ice/ice_main.c > +++ b/drivers/net/ethernet/intel/ice/ice_main.c > @@ -3018,7 +3018,7 @@ static irqreturn_t ice_misc_intr(int __always_unused irq, void *data) > struct iidc_event *event; > > ena_mask &= ~ICE_AUX_CRIT_ERR; > - event = kzalloc(sizeof(*event), GFP_KERNEL); > + event = kzalloc(sizeof(*event), GFP_ATOMIC); > if (event) { > set_bit(IIDC_EVENT_CRIT_ERR, event->type); > /* report the entire OICR value to AUX driver */ What happens next is interesting... event->reg = oicr; ice_send_event_to_aux(pf, event); where: void ice_send_event_to_aux(struct ice_pf *pf, struct iidc_event *event) { struct iidc_auxiliary_drv *iadrv; if (!pf->adev) return; device_lock(&pf->adev->dev); iadrv = ice_get_auxiliary_drv(pf); if (iadrv && iadrv->event_handler) iadrv->event_handler(pf, event); device_unlock(&pf->adev->dev); } device_lock() takes a mutex, not something you should be doing in atomic context. So it looks to me, this handler really should be running in thread context... Andrew
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Lunn <andrew@lunn.ch> To: intel-wired-lan@osuosl.org Subject: [Intel-wired-lan] [PATCH] ice: Don't use GFP_KERNEL in atomic context Date: Sun, 16 Jan 2022 22:42:41 +0100 [thread overview] Message-ID: <YeSRUVmrdmlUXHDn@lunn.ch> (raw) In-Reply-To: <40c94af2f9140794351593047abc95ca65e4e576.1642358759.git.christophe.jaillet@wanadoo.fr> On Sun, Jan 16, 2022 at 07:46:20PM +0100, Christophe JAILLET wrote: > ice_misc_intr() is an irq handler. It should not sleep. > > Use GFP_ATOMIC instead of GFP_KERNEL when allocating some memory. > > Fixes: 348048e724a0 ("ice: Implement iidc operations") > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> > --- > I've never played a lot with irq handler. My understanding is that they > should never sleep. Hi Christophe Threaded interrupt handlers are allowed to sleep. However, this handler is not being used in such a way. So your are probably correct about GFP_KERNEL vs GFP_ATOMIC. > --- > drivers/net/ethernet/intel/ice/ice_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c > index 30814435f779..65de01f3a504 100644 > --- a/drivers/net/ethernet/intel/ice/ice_main.c > +++ b/drivers/net/ethernet/intel/ice/ice_main.c > @@ -3018,7 +3018,7 @@ static irqreturn_t ice_misc_intr(int __always_unused irq, void *data) > struct iidc_event *event; > > ena_mask &= ~ICE_AUX_CRIT_ERR; > - event = kzalloc(sizeof(*event), GFP_KERNEL); > + event = kzalloc(sizeof(*event), GFP_ATOMIC); > if (event) { > set_bit(IIDC_EVENT_CRIT_ERR, event->type); > /* report the entire OICR value to AUX driver */ What happens next is interesting... event->reg = oicr; ice_send_event_to_aux(pf, event); where: void ice_send_event_to_aux(struct ice_pf *pf, struct iidc_event *event) { struct iidc_auxiliary_drv *iadrv; if (!pf->adev) return; device_lock(&pf->adev->dev); iadrv = ice_get_auxiliary_drv(pf); if (iadrv && iadrv->event_handler) iadrv->event_handler(pf, event); device_unlock(&pf->adev->dev); } device_lock() takes a mutex, not something you should be doing in atomic context. So it looks to me, this handler really should be running in thread context... Andrew
next prev parent reply other threads:[~2022-01-16 21:43 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-16 18:46 [PATCH] ice: Don't use GFP_KERNEL in atomic context Christophe JAILLET 2022-01-16 18:46 ` [Intel-wired-lan] " Christophe JAILLET 2022-01-16 21:42 ` Andrew Lunn [this message] 2022-01-16 21:42 ` Andrew Lunn 2022-01-18 20:01 ` Christophe JAILLET 2022-01-18 20:01 ` [Intel-wired-lan] " Christophe JAILLET 2022-02-28 15:07 ` Kaliszczuk, Leszek
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