On Wed, Aug 30, 2023 at 09:23:58PM +0800, Qiujun Huang wrote:
>
>
> > 2023年8月30日 下午5:39，Sudeep Holla <[email protected]> 写道：
> >
> > On Wed, Aug 30, 2023 at 01:07:47AM +0800, Qiujun Huang wrote:
> >> There is a race between the failure of probe and rx_callback (due to a
> >> delayed response).
> >>
> >> scmi_probe
> >> scmi_acquire_protocal
> >> do_xfer
> >> timeout
> >> mailbox_chan_free
> >> <--- delay response
> >> rx_callback
> >> mbox_free_channel
> >> cinfo->transport_info = NULL
> >> mailbox_clear_channel
> >> dereference cinfo->transport_info
> >
> > It is always good to provide the kernel stacktrace which you get when a
> > NULL pointer is dereference. It helps for review and also to document it.
> >
> > --
> > Regards,
> > Sudeep
>
> Get it. Here is the splat.
>
> [ 1.942240][ C0] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000048
> [ 1.942241][ C0] Mem abort info:
> [ 1.942243][ C0] ESR = 0x96000005
> [ 1.944888][ T9] spmi spmi-1: PMIC arbiter version v7 (0x70000000)
> [ 1.950652][ C0] EC = 0x25: DABT (current EL), IL = 32 bits
> [ 1.950653][ C0] SET = 0, FnV = 0
> [ 1.950654][ C0] EA = 0, S1PTW = 0
> [ 1.950656][ C0] Data abort info:
> [ 1.950657][ C0] ISV = 0, ISS = 0x00000005
> [ 1.950658][ C0] CM = 0, WnR = 0
> [ 1.950660][ C0] [0000000000000048] user address but active_mm is swapper
> [ 1.950663][ C0] Internal error: Oops: 96000005 [#1] PREEMPT SMP
> [ 2.338929][ C0] pc : mailbox_clear_channel+0x18/0x64
> [ 2.344384][ C0] lr : scmi_handle_response+0x17c/0x4f4
> [ 2.349923][ C0] sp : ffffffc010003db0
> [ 2.354045][ C0] x29: ffffffc010003dc0 x28: ffffffd85263f000
> [ 2.360216][ C0] x27: ffffffd851621068 x26: ffffffd84ec815c8
> [ 2.366386][ C0] x25: ffffffd85263bf80 x24: ffffffd85263d230
> [ 2.372556][ C0] x23: ffffff803cd70cc0 x22: 0000000000000008
> [ 2.378726][ C0] x21: ffffff8036cf0df8 x20: ffffffd85161bac8
> [ 2.384896][ C0] x19: ffffff8043ffa580 x18: ffffffc010005050
> [ 2.391065][ C0] x17: 0000000000000000 x16: 00000000000000d8
> [ 2.397234][ C0] x15: ffffffd8507965e8 x14: ffffffd84eaebdf0
> [ 2.403404][ C0] x13: 00000000000001ea x12: 0000000000007ffb
> [ 2.409574][ C0] x11: 000000000000ffff x10: ffffffd852c5a000
> [ 2.415744][ C0] x9 : d7be1a9b75f29500 x8 : 0000000000000000
> [ 2.421914][ C0] x7 : 382e31202020205b x6 : ffffffd852c57e7c
> [ 2.428084][ C0] x5 : ffffffffffffffff x4 : 0000000000000000
> [ 2.434254][ C0] x3 : ffffffd84eae6668 x2 : 0000000000000001
> [ 2.440424][ C0] x1 : 0000000000000000 x0 : ffffff8043ffa580
> [ 2.446594][ C0] Call trace:
> [ 2.449819][ C0] mailbox_clear_channel+0x18/0x64
Is this with latest kernel ? IIUC the mailbox_clear_channel should get called
only for delayed response and notification in this path(scmi_handle_response).
You are saying it happens as part of probe and again IIUC probe doesn't have
any delayed response command. What am I missing ?
Any additional changes in the tree ? My build has much smaller
mailbox_clear_channel.
> [ 2.454916][ C0] scmi_handle_response+0x17c/0x4f4
> [ 2.460100][ C0] rx_callback+0x60/0xec
> [ 2.464311][ C0] mbox_chan_received_data+0x44/0x94
> [ 2.469584][ C0] qcom_rimps_rx_interrupt+0xc0/0x144 [qcom_rimps]
This suggests out of tree driver, any pointers ?
Also I vaguely remember discussing this in the past. Perhaps at [1] or
somewhere else.
--
Regards,
Sudeep
[1] https://lore.kernel.org/linux-arm-kernel/[email protected]/