Re: [PATCH v1] firmware: arm_scmi: Fix NULL pointer dereference in mailbox_clear_channel
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From: Qiujun Huang <hidden>
Date: 2023-08-31 14:49:46
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On Thu, Aug 31, 2023 at 8:34 PM Sudeep Holla [off-list ref] wrote:
On Wed, Aug 30, 2023 at 09:23:58PM +0800, Qiujun Huang wrote:quoted
quoted
2023年8月30日 下午5:39，Sudeep Holla [off-list ref] 写道： On Wed, Aug 30, 2023 at 01:07:47AM +0800, Qiujun Huang wrote:quoted
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_infoIt 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, SudeepGet 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+0x18/0x64Is this with latest kernel ? IIUC the mailbox_clear_channel should get called
no, it's on 5.10-stable kernel
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.quoted
[ 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.
Get that. It looks painful
-- Regards, Sudeep [1] https://lore.kernel.org/linux-arm-kernel/cfa26ff3-c95a-1986-58fc-b49fc9be49d5@quicinc.com/ (local)
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