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Date:   Thu, 3 Jun 2021 13:40:43 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Alexandru Elisei <alexandru.elisei@arm.com>
Cc:     Felipe Balbi <balbi@kernel.org>, p.zabel@pengutronix.de,
        linux-usb@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        arm-mail-list <linux-arm-kernel@lists.infradead.org>,
        sanm@codeaurora.org
Subject: Re: [BUG] usb: dwc3: Kernel NULL pointer dereference in dwc3_remove()
Message-ID: <YLi/u9J5f+nQO4Cm@kroah.com>
References: <c3c75895-313a-5be7-6421-b32bac741a88@arm.com>
 <87r1hjcvf6.fsf@kernel.org>
 <70be179c-d36b-de6f-6efc-2888055b1312@arm.com>
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On Thu, Jun 03, 2021 at 11:41:45AM +0100, Alexandru Elisei wrote:
> Hello Felipe,
> 
> Thank you for having a look!
> 
> On 6/3/21 7:30 AM, Felipe Balbi wrote:
> > Hi,
> >
> > Alexandru Elisei <alexandru.elisei@arm.com> writes:
> >> I've been seeing the following panic when shutting down my rockpro64:
> >>
> >> [?? 21.459064] xhci-hcd xhci-hcd.0.auto: USB bus 5 deregistered
> >> [?? 21.683077] Unable to handle kernel NULL pointer dereference at virtual address
> >> 00000000000000a0
> >> [?? 21.683858] Mem abort info:
> >> [?? 21.684104]?? ESR = 0x96000004
> >> [?? 21.684375]?? EC = 0x25: DABT (current EL), IL = 32 bits
> >> [?? 21.684841]?? SET = 0, FnV = 0
> >> [?? 21.685111]?? EA = 0, S1PTW = 0
> >> [?? 21.685389] Data abort info:
> >> [?? 21.685644]?? ISV = 0, ISS = 0x00000004
> >> [?? 21.686024]?? CM = 0, WnR = 0
> >> [?? 21.686288] user pgtable: 4k pages, 48-bit VAs, pgdp=000000000757a000
> >> [?? 21.686853] [00000000000000a0] pgd=0000000000000000, p4d=0000000000000000
> >> [?? 21.687452] Internal error: Oops: 96000004EEMPT SMP
> >> [?? 21.687941] Modules linked in:
> >> [?? 21.688214] CPU: 4 PID: 1 Comm: shutdown Not tainted
> >> 5.12.0-rc7-00262-g568262bf5492 #33
> >> [?? 21.688915] Hardware name: Pine64 RockPro64 v2.0 (DT)
> >> [?? 21.689357] pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--)
> >> [?? 21.689884] pc : down_read_interruptible+0xec/0x200
> >> [?? 21.690321] lr : simple_recursive_removal+0x48/0x280
> >> [?? 21.690761] sp : ffff800011f4b940
> >> [?? 21.691053] x29: ffff800011f4b940 x28: ffff000000809b40
> >> [?? 21.691522] x27: ffff000000809b98 x26: ffff8000114f5170
> >> [?? 21.691990] x25: 00000000000000a0 x24: ffff800011e84030
> >> [?? 21.692459] x23: 0000000000000080 x22: 0000000000000000
> >> [?? 21.692927] x21: ffff800011ecaa5c x20: ffff800011ecaa60
> >> [?? 21.693395] x19: ffff000000809b40 x18: ffffffffffffffff
> >> [?? 21.693863] x17: 0000000000000000 x16: 0000000000000000
> >> [?? 21.694331] x15: ffff800091f4ba6d x14: 0000000000000004
> >> [?? 21.694799] x13: 0000000000000000 x12: 0000000000000020
> >> [?? 21.695267] x11: 0101010101010101 x10: 7f7f7f7f7f7f7f7f
> >> [?? 21.695735] x9 : 6f6c746364716e62 x8 : 7f7f7f7f7f7f7f7f
> >> [?? 21.696203] x7 : fefefeff6364626d x6 : 0000000000001bd8
> >> [?? 21.696671] x5 : 0000000000000000 x4 : 0000000000000000
> >> [?? 21.697138] x3 : 00000000000000a0 x2 : 0000000000000001
> >> [?? 21.697606] x1 : 0000000000000000 x0 : 00000000000000a0
> >> [?? 21.698075] Call trace:
> >> [?? 21.698291]? down_read_interruptible+0xec/0x200
> >> [?? 21.698690]? debugfs_remove+0x60/0x84
> >> [?? 21.699016]? dwc3_debugfs_exit+0x1c/0x6c
> >> [?? 21.699363]? dwc3_remove+0x34/0x1a0
> >> [?? 21.699672]? platform_remove+0x28/0x60
> >> [?? 21.700005]? __device_release_driver+0x188/0x230
> >> [?? 21.700414]? device_release_driver+0x2c/0x44
> >> [?? 21.700791]? bus_remove_device+0x124/0x130
> >> [?? 21.701154]? device_del+0x168/0x420
> >> [?? 21.701462]? platform_device_del.part.0+0x1c/0x90
> >> [?? 21.701877]? platform_device_unregister+0x28/0x44
> >> [?? 21.702291]? of_platform_device_destroy+0xe8/0x100
> >> [?? 21.702716]? device_for_each_child_reverse+0x64/0xb4
> >> [?? 21.703153]? of_platform_depopulate+0x40/0x84
> >> [?? 21.703538]? __dwc3_of_simple_teardown+0x20/0xd4
> >> [?? 21.703945]? dwc3_of_simple_shutdown+0x14/0x20
> >> [?? 21.704337]? platform_shutdown+0x28/0x40
> >> [?? 21.704683]? device_shutdown+0x158/0x330
> >> [?? 21.705029]? kernel_power_off+0x38/0x7c
> >> [?? 21.705372]? __do_sys_reboot+0x16c/0x2a0
> >> [?? 21.705719]? __arm64_sys_reboot+0x28/0x34
> >> [?? 21.706074]? el0_svc_common.constprop.0+0x60/0x120
> >> [?? 21.706499]? do_el0_svc+0x28/0x94
> >> [?? 21.706794]? el0_svc+0x2c/0x54
> >> [?? 21.707067]? el0_sync_handler+0xa4/0x130
> >> [?? 21.707414]? el0_sync+0x170/0x180
> >> [?? 21.707711] Code: c8047c62 35ffff84 17fffe5f f9800071 (c85ffc60)
> >> [?? 21.708250] ---[ end trace 5ae08147542eb468 ]---
> >> [?? 21.708667] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
> >> [?? 21.709456] Kernel Offset: disabled
> >> [?? 21.709762] CPU features: 0x00240022,2100600c
> >> [?? 21.710146] Memory Limit: 2048 MB
> >> [?? 21.710443] ---[ end Kernel panic - not syncing: Attempted to kill init!
> >> exitcode=0x0000000b ]---
> >>
> >> I've been able to bisect the panic and the offending commit is 568262bf5492 ("usb:
> >> dwc3: core: Add shutdown callback for dwc3"). I can provide more diagnostic
> >> information if needed and I can help test the fix.
> > if you simply revert that commit in HEAD, does the problem really go
> > away?
> 
> Kernel built from commit 324c92e5e0ee, which is the kernel tip today, the panic is
> there. Reverting the offending commit, 568262bf5492, makes the panic disappear.

Want to send a revert so I can take it now?