> -----Original Message----- > From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> > Sent: Monday, November 8, 2021 8:56 PM > To: 胡启航(Nick Hu) <huqihang@xxxxxxxx> > Cc: balbi@xxxxxxxxxx; peter.chen@xxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v2] usb: gadget: composite: Fix null pointer exception > > On Mon, Nov 08, 2021 at 12:42:24PM +0000, 胡启航(Nick Hu) wrote: > > > -----Original Message----- > > > From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> > > > Sent: Friday, November 5, 2021 8:45 PM > > > To: 胡启航(Nick Hu) <huqihang@xxxxxxxx> > > > Cc: balbi@xxxxxxxxxx; peter.chen@xxxxxxxxxx; > > > linux-usb@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > > > Subject: Re: [PATCH v2] usb: gadget: composite: Fix null pointer > > > exception > > > > > > On Fri, Nov 05, 2021 at 06:48:40PM +0800, Qihang Hu wrote: > > > > In the config_ep_by_speed_and_alt function, select the > > > > corresponding descriptor through g->speed, but the function driver > > > > may not support the corresponding speed. So, we need to check > > > > whether the function 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 > > > > > > So this is an invalid driver causing this problem? Or can this be > > > triggered by userspace? > > > > Yes, if the kernel is loaded with an interface driver that does not > > support all speeds, this problem can be triggered in userspace. > > What in-kernel driver does not support all speeds that can trigger this? > > Why not fix the drivers? This problem is caused by android f_audio_source.c I think the core driver code should be improved to make it less susceptible to function-driven influence. Of course, repairing the function driver is the fundamental solution to the problem. > > > > [ 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@xxxxxxxx> > > > > > > What commit id does this fix? > > > > I have not submitted a BUG. > > I will study and submit a BUG as soon as possible. > > I do not understand what you mean by this. I am asking what commit caused > this problem so we can mark this one as fixing it. > This is a problem with Android's driver code. The kernel does not include it. Thanks
