Messages in this thread | | | Subject | Re: [PATCH] memory: mtk-smi: Fix a null dereference for the ostd | From | Krzysztof Kozlowski <> | Date | Fri, 29 Oct 2021 19:35:45 +0200 |
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On 28/10/2021 07:50, Yong Wu wrote: > We add the ostd setting for mt8195. It introduces a abort for the > previous SoC which doesn't have ostd setting. This is the log: > > Unable to handle kernel NULL pointer dereference at virtual address > 0000000000000080 > ... > pc : mtk_smi_larb_config_port_gen2_general+0x64/0x130 > lr : mtk_smi_larb_resume+0x54/0x98 > ... > Call trace: > mtk_smi_larb_config_port_gen2_general+0x64/0x130 > pm_generic_runtime_resume+0x2c/0x48 > __genpd_runtime_resume+0x30/0xa8 > genpd_runtime_resume+0x94/0x2c8 > __rpm_callback+0x44/0x150 > rpm_callback+0x6c/0x78 > rpm_resume+0x310/0x558 > __pm_runtime_resume+0x3c/0x88 > > In the code: larbostd = larb->larb_gen->ostd[larb->larbid], > if "larb->larb_gen->ostd" is null, the "larbostd" is the offset, it is > also a valid value, thus, use the larb->larb_gen->ostd as the condition > inside the "for" loop.
You need to write more clearly, what you are fixing here.
> > Signed-off-by: Yong Wu <yong.wu@mediatek.com> > --- > Hi Krzysztof, > Could you help review and conside this as a fix for the mt8195 patchset? > The mt8195 patchset are not in mainline, thus, I don't know its sha-id, > and don't add Fixes tag. > Thanks > --- > drivers/memory/mtk-smi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c > index b883dcc0bbfa..0262a59a2d6e 100644 > --- a/drivers/memory/mtk-smi.c > +++ b/drivers/memory/mtk-smi.c > @@ -257,7 +257,7 @@ static void mtk_smi_larb_config_port_gen2_general(struct device *dev) > if (MTK_SMI_CAPS(flags_general, MTK_SMI_FLAG_SW_FLAG)) > writel_relaxed(SMI_LARB_SW_FLAG_1, larb->base + SMI_LARB_SW_FLAG); > > - for (i = 0; i < SMI_LARB_PORT_NR_MAX && larbostd && !!larbostd[i]; i++) > + for (i = 0; i < SMI_LARB_PORT_NR_MAX && larb->larb_gen->ostd && !!larbostd[i]; i++) > writel_relaxed(larbostd[i], larb->base + SMI_LARB_OSTDL_PORTx(i));
The code does not look good. You have already a dereference at line 244:
const u8 *larbostd = larb->larb_gen->ostd[larb->larbid];
You are not fixing the NULL pointer dereference.
> > for_each_set_bit(i, (unsigned long *)larb->mmu, 32) { >
Best regards, Krzysztof
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