Messages in this thread |  | | From | Ulf Hansson <> | | Date | Tue, 30 Jan 2024 14:09:20 +0100 | | Subject | Re: [PATCH] pmdomain: arm: Fix NULL dereference on scmi_perf_domain removal |
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On Thu, 25 Jan 2024 at 20:18, Cristian Marussi <cristian.marussi@arm.com> wrote: > > On unloading of the scmi_perf_domain module got the below splat, when in > the DT provided to the system under test the '#power-domain-cells' property > was missing. > Indeed, this particular setup causes the probe to bail out early without > giving any error, so that, then, the removal code is run on unload, but > without all the expected initialized structures in place. > > Add a check and bail out early on remove too.
Thanks for spotting this!
> > Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 > Mem abort info: > ESR = 0x0000000096000004 > EC = 0x25: DABT (current EL), IL = 32 bits > SET = 0, FnV = 0 > EA = 0, S1PTW = 0 > FSC = 0x04: level 0 translation fault > Data abort info: > ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 > CM = 0, WnR = 0, TnD = 0, TagAccess = 0 > GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 > user pgtable: 4k pages, 48-bit VAs, pgdp=00000001076e5000 > [0000000000000008] pgd=0000000000000000, p4d=0000000000000000 > Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP > Modules linked in: scmi_perf_domain(-) scmi_module scmi_core > CPU: 0 PID: 231 Comm: rmmod Not tainted 6.7.0-00084-gb4b1f27d3b83-dirty #15 > Hardware name: linux,dummy-virt (DT) > pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) > pc : scmi_perf_domain_remove+0x28/0x70 [scmi_perf_domain] > lr : scmi_perf_domain_remove+0x28/0x70 [scmi_perf_domain] > sp : ffff80008393bc10 > x29: ffff80008393bc10 x28: ffff0000875a8000 x27: 0000000000000000 > x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 > x23: ffff00008030c090 x22: ffff00008032d490 x21: ffff80007b287050 > x20: 0000000000000000 x19: ffff00008032d410 x18: 0000000000000000 > x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 > x14: 8ba0696d05013a2f x13: 0000000000000000 x12: 0000000000000002 > x11: 0101010101010101 x10: ffff00008510cff8 x9 : ffff800080a6797c > x8 : 0101010101010101 x7 : 7f7f7f7f7f7f7f7f x6 : fefefeff6364626d > x5 : 8080808000000000 x4 : 0000000000000020 x3 : 00000000553a3dc1 > x2 : ffff0000875a8000 x1 : ffff0000875a8000 x0 : ffff800082ffa048 > Call trace: > scmi_perf_domain_remove+0x28/0x70 [scmi_perf_domain] > scmi_dev_remove+0x28/0x40 [scmi_core] > device_remove+0x54/0x90 > device_release_driver_internal+0x1dc/0x240 > driver_detach+0x58/0xa8 > bus_remove_driver+0x78/0x108 > driver_unregister+0x38/0x70 > scmi_driver_unregister+0x28/0x180 [scmi_core] > scmi_perf_domain_driver_exit+0x18/0xb78 [scmi_perf_domain] > __arm64_sys_delete_module+0x1a8/0x2c0 > invoke_syscall+0x50/0x128 > el0_svc_common.constprop.0+0x48/0xf0 > do_el0_svc+0x24/0x38 > el0_svc+0x34/0xb8 > el0t_64_sync_handler+0x100/0x130 > el0t_64_sync+0x190/0x198 > Code: a90153f3 f9403c14 f9414800 955f8a05 (b9400a80) > ---[ end trace 0000000000000000 ]--- > > Cc: Sudeep Holla <sudeep.holla@arm.com> > Cc: Ulf Hansson <ulf.hansson@linaro.org> > Fixes: 2af23ceb8624 ("pmdomain: arm: Add the SCMI performance domain") > Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> > --- > I suppose the probe does NOT bail out with an error because this DT config has > to be supported, right ?
Actually, no. It's a mistake by me, the probe should bail out with an error code.
In fact, there is also one additional similar problem in probe, when the number of perf-domains are zero. In that case, we should also return an error code, rather than returning 0.
Would you mind updating the patch to cover both problems - or if you are too busy, just let me know and I can help out.
> --- > drivers/pmdomain/arm/scmi_perf_domain.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/pmdomain/arm/scmi_perf_domain.c b/drivers/pmdomain/arm/scmi_perf_domain.c > index 709bbc448fad..d7ef46ccd9b8 100644 > --- a/drivers/pmdomain/arm/scmi_perf_domain.c > +++ b/drivers/pmdomain/arm/scmi_perf_domain.c > @@ -159,6 +159,9 @@ static void scmi_perf_domain_remove(struct scmi_device *sdev) > struct genpd_onecell_data *scmi_pd_data = dev_get_drvdata(dev); > int i; > > + if (!scmi_pd_data) > + return; > + > of_genpd_del_provider(dev->of_node); > > for (i = 0; i < scmi_pd_data->num_domains; i++) > -- > 2.43.0 >
Kind regards Uffe
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