| Message ID | 20211026173943.6829-2-s.shtylyov@omp.ru (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,01/22] usb: host: ehci-exynos: deny IRQ0 | expand |
On Tue, Oct 26, 2021 at 08:39:22PM +0300, Sergey Shtylyov wrote: > If platform_get_irq() returns IRQ0 (considered invalid according to Linus) > the driver blithely passes it to usb_add_hcd() that treats IRQ0 as no IRQ > at all. Deny IRQ0 right away, returning -EINVAL from the probe() method... > > Fixes: 44ed240d6273 ("usb: host: ehci-exynos: Fix error check in exynos_ehci_probe()") > Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru> > Acked-by: Alan Stern <stern@rowland.harvard.edu> > --- > Changes in version 2: > - added Alan's ACK. > > drivers/usb/host/ehci-exynos.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/usb/host/ehci-exynos.c b/drivers/usb/host/ehci-exynos.c > index 1a9b7572e17f..ff4e1261801a 100644 > --- a/drivers/usb/host/ehci-exynos.c > +++ b/drivers/usb/host/ehci-exynos.c > @@ -207,6 +207,10 @@ static int exynos_ehci_probe(struct platform_device *pdev) > err = irq; > goto fail_io; > } > + if (!irq) { > + err = -EINVAL; > + goto fail_io; > + } This is a huge sign that the api being used here is broken. Please fix the root cause here, if returning a 0 is an error, then have the function you called to get this irq return an error. Otherwise you will have to fix ALL callers, and people will always get it wrong. Fix the root cause here, don't paper it over. thanks, greg k-h
Hello! On 10/30/21 11:54 AM, Greg Kroah-Hartman wrote: >> If platform_get_irq() returns IRQ0 (considered invalid according to Linus) >> the driver blithely passes it to usb_add_hcd() that treats IRQ0 as no IRQ >> at all. Deny IRQ0 right away, returning -EINVAL from the probe() method... >> >> Fixes: 44ed240d6273 ("usb: host: ehci-exynos: Fix error check in exynos_ehci_probe()") >> Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru> >> Acked-by: Alan Stern <stern@rowland.harvard.edu> >> --- >> Changes in version 2: >> - added Alan's ACK. >> >> drivers/usb/host/ehci-exynos.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/usb/host/ehci-exynos.c b/drivers/usb/host/ehci-exynos.c >> index 1a9b7572e17f..ff4e1261801a 100644 >> --- a/drivers/usb/host/ehci-exynos.c >> +++ b/drivers/usb/host/ehci-exynos.c >> @@ -207,6 +207,10 @@ static int exynos_ehci_probe(struct platform_device *pdev) >> err = irq; >> goto fail_io; >> } >> + if (!irq) { >> + err = -EINVAL; >> + goto fail_io; >> + } > > This is a huge sign that the api being used here is broken. And you're telling me that after I've wasted time on v2? :-( Well, at least the series had couple blunders, so it couldn't merged for 5.16-rc1 anyway (not sure why these weren't detected in v1). > Please fix the root cause here, if returning a 0 is an error, then have > the function you called to get this irq return an error. Well, technically not, although that doesn't match the kernel-doc for the function now. I only don't understand why returning IRQ0 hasn't been replaced still... > Otherwise you > will have to fix ALL callers, and people will always get it wrong. > Fix the root cause here, don't paper it over. As I have already told you, I won't have to do it as filtering out is only needed iff 0 is used as an indication for something special. IRQ0 is still perfectly valid for request_irq() and is even called by arch/{aplha|mips|x86}... > thanks, > > greg k-h MBR, Sergey
On Mon, Nov 01, 2021 at 11:39:13PM +0300, Sergey Shtylyov wrote: > Hello! > > On 10/30/21 11:54 AM, Greg Kroah-Hartman wrote: > > >> If platform_get_irq() returns IRQ0 (considered invalid according to Linus) > >> the driver blithely passes it to usb_add_hcd() that treats IRQ0 as no IRQ > >> at all. Deny IRQ0 right away, returning -EINVAL from the probe() method... > >> > >> Fixes: 44ed240d6273 ("usb: host: ehci-exynos: Fix error check in exynos_ehci_probe()") > >> Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru> > >> Acked-by: Alan Stern <stern@rowland.harvard.edu> > >> --- > >> Changes in version 2: > >> - added Alan's ACK. > >> > >> drivers/usb/host/ehci-exynos.c | 4 ++++ > >> 1 file changed, 4 insertions(+) > >> > >> diff --git a/drivers/usb/host/ehci-exynos.c b/drivers/usb/host/ehci-exynos.c > >> index 1a9b7572e17f..ff4e1261801a 100644 > >> --- a/drivers/usb/host/ehci-exynos.c > >> +++ b/drivers/usb/host/ehci-exynos.c > >> @@ -207,6 +207,10 @@ static int exynos_ehci_probe(struct platform_device *pdev) > >> err = irq; > >> goto fail_io; > >> } > >> + if (!irq) { > >> + err = -EINVAL; > >> + goto fail_io; > >> + } > > > > This is a huge sign that the api being used here is broken. > > And you're telling me that after I've wasted time on v2? :-( Well, at least the series had > couple blunders, so it couldn't merged for 5.16-rc1 anyway (not sure why these weren't detected > in v1). I thought about it some more and noticed it on your v2 submission. > > Please fix the root cause here, if returning a 0 is an error, then have > > the function you called to get this irq return an error. > > Well, technically not, although that doesn't match the kernel-doc for the function now. > I only don't understand why returning IRQ0 hasn't been replaced still... Then please work on that. > > Otherwise you > > will have to fix ALL callers, and people will always get it wrong. > > Fix the root cause here, don't paper it over. > > As I have already told you, I won't have to do it as filtering out is only needed iff 0 is > used as an indication for something special. IRQ0 is still perfectly valid for request_irq() > and is even called by arch/{aplha|mips|x86}... If it is valid, then why can it not be a valid irq for all of these drivers that you are changing here? What is preventing them from running on the platforms where 0 is a valid irq value? thanks, greg k-h
HEllo! On 11/2/21 4:55 PM, Greg Kroah-Hartman wrote: [...] >>>> If platform_get_irq() returns IRQ0 (considered invalid according to Linus) >>>> the driver blithely passes it to usb_add_hcd() that treats IRQ0 as no IRQ >>>> at all. Deny IRQ0 right away, returning -EINVAL from the probe() method... >>>> >>>> Fixes: 44ed240d6273 ("usb: host: ehci-exynos: Fix error check in exynos_ehci_probe()") >>>> Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru> >>>> Acked-by: Alan Stern <stern@rowland.harvard.edu> [...] >>> Otherwise you >>> will have to fix ALL callers, and people will always get it wrong. >>> Fix the root cause here, don't paper it over. >> >> As I have already told you, I won't have to do it as filtering out is only needed iff 0 is >> used as an indication for something special. IRQ0 is still perfectly valid for request_irq() >> and is even called by arch/{aplha|mips|x86}... "And the latter is called with 0 by", I meant to type... :-/ The arguments I've heard for this ambiguity to continue were that IRQ0 is requested only with setup_irq() (no longer true) and that these calls are confined to the arch code (still true). > If it is valid, then why can it not be a valid irq for all of these > drivers that you are changing here? What is preventing them from > running on the platforms where 0 is a valid irq value? These drivers call usb_add_hcd() that only calls request_irq() (via usb_hcd_request_irqs()) if IRQ # is non-zero -- otherwise the driver is supposed to handle the interrupt itself (if it needs one?) --thus calling usb_add_hcd() with IRQ0 results in non-working HCD without IRQs... (For libata, ata_host_activate() (called in the end of the driver's probe() methods) checks if the 'irq' parameter is 0 early and in this case warns about the 'irq_handler' parameter being non-NULL and calls ata_host_register() without registering the IRQ handler and expects the driver to set the polling flag, thus if IRQ0 is passed from an (unsuspecting) ATA driver, one gets not fully functional host driver).) > thanks, > > greg k-h MBR, Sergey
diff --git a/drivers/usb/host/ehci-exynos.c b/drivers/usb/host/ehci-exynos.c index 1a9b7572e17f..ff4e1261801a 100644 --- a/drivers/usb/host/ehci-exynos.c +++ b/drivers/usb/host/ehci-exynos.c @@ -207,6 +207,10 @@ static int exynos_ehci_probe(struct platform_device *pdev) err = irq; goto fail_io; } + if (!irq) { + err = -EINVAL; + goto fail_io; + } err = exynos_ehci_phy_enable(&pdev->dev); if (err) {
If platform_get_irq() returns IRQ0 (considered invalid according to Linus) the driver blithely passes it to usb_add_hcd() that treats IRQ0 as no IRQ at all. Deny IRQ0 right away, returning -EINVAL from the probe() method... Fixes: 44ed240d6273 ("usb: host: ehci-exynos: Fix error check in exynos_ehci_probe()") Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru> Acked-by: Alan Stern <stern@rowland.harvard.edu> --- Changes in version 2: - added Alan's ACK. drivers/usb/host/ehci-exynos.c | 4 ++++ 1 file changed, 4 insertions(+)