Messages in this thread | | | Date | Mon, 1 Nov 2021 21:18:49 +0800 | From | Peter Chen <> | Subject | Re: [PATCH] usb: gadget: composite: Fix null pointer exception |
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On 21-11-01 09:57:57, Qihang Hu wrote: > In the config_ep_by_speed_and_alt function, select the corresponding > descriptor through g->speed, but the interface driver
function driver
> may not > support the corresponding speed. So, we need to check whether the > interface driver provides the corresponding speed descriptor when > selecting the descriptor. > > [ 237.708146] android_work: sent uevent USB_STATE=CONNECTED > [ 237.712464] kconfigfs-gadget gadget: super-speed config #1: b > [ 237.712487] kUnable to handle kernel NULL pointer dereference at virtual address 0000000000000000 > [ 237.712493] kMem abort info: > [ 237.712498] k ESR = 0x96000006 > [ 237.712504] k EC = 0x25: DABT (current EL), IL = 32 bits > [ 237.712510] k SET = 0, FnV = 0 > [ 237.712515] k EA = 0, S1PTW = 0 > [ 237.712520] kData abort info: > [ 237.712525] k ISV = 0, ISS = 0x00000006 > [ 237.712530] k CM = 0, WnR = 0 > [ 237.712536] kuser pgtable: 4k pages, 39-bit VAs, pgdp=000000020ef29000 > [ 237.712541] k[0000000000000000] pgd=000000020ef2a003, pud=000000020ef2a003, pmd=0000000000000000 > [ 237.712554] kInternal error: Oops: 96000006 [#1] PREEMPT SMP > [ 237.722067] kSkip md ftrace buffer dump for: 0x1609e0 > [ 237.787037] kWorkqueue: dwc_wq dwc3_bh_work.cfi_jt > [ 237.854922] kpstate: 60c00085 (nZCv daIf +PAN +UAO) > [ 237.863165] kpc : config_ep_by_speed_and_alt+0x90/0x308 > [ 237.871766] klr : audio_set_alt+0x54/0x78 > [ 237.879108] ksp : ffffffc0104839e0 > > Signed-off-by: Qihang Hu <huqihang@oppo.com> > --- > drivers/usb/gadget/composite.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c > index 72a9797dbbae..443a65af98af 100644 > --- a/drivers/usb/gadget/composite.c > +++ b/drivers/usb/gadget/composite.c > @@ -166,21 +166,21 @@ int config_ep_by_speed_and_alt(struct usb_gadget *g, > /* select desired speed */ > switch (g->speed) { > case USB_SPEED_SUPER_PLUS: > - if (gadget_is_superspeed_plus(g)) { > + if (gadget_is_superspeed_plus(g) && f->ssp_descriptors) { > speed_desc = f->ssp_descriptors; > want_comp_desc = 1; > break; > } > fallthrough; > case USB_SPEED_SUPER: > - if (gadget_is_superspeed(g)) { > + if (gadget_is_superspeed(g) && f->ss_descriptors) { > speed_desc = f->ss_descriptors; > want_comp_desc = 1; > break; > } > fallthrough; > case USB_SPEED_HIGH: > - if (gadget_is_dualspeed(g)) { > + if (gadget_is_dualspeed(g) && f->hs_descriptors) { > speed_desc = f->hs_descriptors; > break; > } > -- > 2.25.1 >
Besides your fix, you may show an warning that said "the function doesn't hold the descriptors for supported speed, using the default (FS) descriptors". See below kernel doc for detail.
/** * config_ep_by_speed_and_alt() - configures the given endpoint * * .... * Note: the supplied function should hold all the descriptors * for supported speeds */
What's more, you may fix android f_audio_source.c, and let it support super speed and super speed plus.
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Thanks, Peter Chen
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