Messages in this thread | | | Date | Tue, 18 Jan 2022 21:01:30 +0100 | Subject | Re: [PATCH] ice: Don't use GFP_KERNEL in atomic context | From | Christophe JAILLET <> |
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Le 16/01/2022 à 22:42, Andrew Lunn a écrit : > 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 >
Ok, thanks for the explanation.
ice_misc_intr() is registered with devm_request_irq(), so it is a handler that can't sleep.
I guess that more consideration should be taken into account than only: s/devm_request_irq(handler)/devm_request_threaded_irq(NULL, handler)/
So I'll leave this one to people with the expected know-how.
If my s/GFP_KERNEL/GFP_ATOMIC/ makes enough sense as-is, that's fine for me, but it looks that another solution is needed to fix the 2nd issue.
CJ
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