Re: [syzbot] [usb?] BUG: unable to handle kernel paging request in xhci_halt

[Aleksandr Nogikh]

#syz invalid

See the discussion at
https://lore.kernel.org/all/6a88012e.dbb3a75c.13dd47.0007.GAE@xxxxxxxxxx/T/

On Fri, Aug 21, 2026 at 9:52 AM syzbot
<syzbot+c90273bf9017ef1462af@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    21d6ac051080 Merge branch 'for-next/core' into for-kernelci
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> console output: https://syzkaller.appspot.com/x/log.txt?x=1366d949580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=d1128bc53f2ef7f3
> dashboard link: https://syzkaller.appspot.com/bug?extid=c90273bf9017ef1462af
> compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
> userspace arch: arm64
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1741d6c6580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11d03a79580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/88380e2ddcb9/disk-21d6ac05.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/5dba5c2896b7/vmlinux-21d6ac05.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/52ac739e37e0/Image-21d6ac05.gz.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+c90273bf9017ef1462af@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> EXT4-fs (nvme0n1p2): shut down requested (2)
> Aborting journal on device nvme0n1p2-8.
> xhci_hcd 0000:00:02.0: xHCI Host Controller
> xhci_hcd 0000:00:02.0: new USB bus registered, assigned bus number 34
> Unable to handle kernel paging request at virtual address ffff8000936e40ff
> KASAN: probably user-memory-access in range [0x000000049b7207f8-0x000000049b7207ff]
> Mem abort info:
>   ESR = 0x0000000096000021
>   EC = 0x25: DABT (current EL), IL = 32 bits
>   SET = 0, FnV = 0
>   EA = 0, S1PTW = 0
>   FSC = 0x21: alignment fault
> Data abort info:
>   ISV = 0, ISS = 0x00000021, ISS2 = 0x00000000
>   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
>   GCS = 0, Overlay = 0, DirtyBit = 0
> swapper pgtable: 4k pages, 48-bit VAs, pgdp=000000021b049000
> [ffff8000936e40ff] pgd=0000000000000000, p4d=1000000221341003, pud=1000000221342003, pmd=1000000106b4b403, pte=0068010000000713
> Internal error: Oops: 0000000096000021 [#1]  SMP
> Modules linked in:
> CPU: 1 UID: 0 PID: 4935 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
> pstate: 63400005 (nZCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
> pc : __raw_readl arch/arm64/include/asm/io.h:84 [inline]
> pc : readl include/asm-generic/io.h:231 [inline]
> pc : xhci_quiesce drivers/usb/host/xhci.c:107 [inline]
> pc : xhci_halt+0x64/0x1ec drivers/usb/host/xhci.c:125
> lr : xhci_halt+0x40/0x1ec drivers/usb/host/xhci.c:124
> sp : ffff8000963773c0
> x29: ffff8000963773c0 x28: ffff0000d23fa000 x27: dfff800000000000
> x26: ffff0000d23fa418 x25: 0000000000000f01 x24: ffff0000d23fa6e8
> x23: ffff0000c2f4a0d0 x22: ffff0000d23fa418 x21: dfff800000000000
> x20: 1fffe0001a47f483 x19: ffff0000d23fa400 x18: 00000000ffffffff
> x17: ffff80008a7d6000 x16: 0000000000000005 x15: ffff80008a35fda0
> x14: ffff80008a5d5e28 x13: 0000000000000004 x12: 0000000000000000
> x11: ffff8000963772e0 x10: 00000000fffffbf2 x9 : 2afdbc7a43e86800
> x8 : ffff8000936e40ff x7 : 0000000000000000 x6 : 0000000000000000
> x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff8000833104ec
> x2 : 0000000000000002 x1 : ffff0000c4ec57c0 x0 : 0000000000000000
> Call trace:
>  __raw_readl arch/arm64/include/asm/io.h:84 [inline] (P)
>  readl include/asm-generic/io.h:231 [inline] (P)
>  xhci_quiesce drivers/usb/host/xhci.c:107 [inline] (P)
>  xhci_halt+0x64/0x1ec drivers/usb/host/xhci.c:125 (P)
>  xhci_gen_setup+0x5d8/0x111c drivers/usb/host/xhci.c:5496
>  xhci_pci_setup+0x110/0x44c drivers/usb/host/xhci-pci.c:579
>  usb_add_hcd+0x5c4/0xdec drivers/usb/core/hcd.c:2935
>  usb_hcd_pci_probe+0x63c/0xaa4 drivers/usb/core/hcd-pci.c:267
>  xhci_pci_common_probe+0x90/0x760 drivers/usb/host/xhci-pci.c:633
>  xhci_pci_probe+0x44/0xdc drivers/usb/host/xhci-pci.c:717
>  local_pci_probe+0xc8/0x158 drivers/pci/pci-driver.c:332
>  pci_call_probe drivers/pci/pci-driver.c:394 [inline]
>  __pci_device_probe drivers/pci/pci-driver.c:455 [inline]
>  pci_device_probe+0x460/0x8d4 drivers/pci/pci-driver.c:489
>  call_driver_probe drivers/base/dd.c:-1 [inline]
>  really_probe+0x29c/0x800 drivers/base/dd.c:706
>  __driver_probe_device+0x1e0/0x350 drivers/base/dd.c:868
>  device_driver_attach+0x58/0xac drivers/base/dd.c:1203
>  bind_store+0xf4/0x14c drivers/base/bus.c:267
>  drv_attr_store+0x80/0xa4 drivers/base/bus.c:125
>  sysfs_kf_write+0xe0/0x108 fs/sysfs/file.c:145
>  kernfs_fop_write_iter+0x260/0x3b8 fs/kernfs/file.c:345
>  new_sync_write fs/read_write.c:595 [inline]
>  vfs_write+0x51c/0xa0c fs/read_write.c:687
>  ksys_write+0x12c/0x228 fs/read_write.c:739
>  __do_sys_write fs/read_write.c:750 [inline]
>  __se_sys_write fs/read_write.c:747 [inline]
>  __arm64_sys_write+0x84/0x98 fs/read_write.c:747
>  __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
>  invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
>  el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
>  do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
>  el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
>  el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
>  el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590
> Code: 9762248f f94002c8 128081aa d503201f (b9400108)
> ---[ end trace 0000000000000000 ]---
> ----------------
> Code disassembly (best guess):
>    0:   9762248f        bl      0xfffffffffd88923c
>    4:   f94002c8        ldr     x8, [x22]
>    8:   128081aa        mov     w10, #0xfffffbf2                // #-1038
>    c:   d503201f        nop
> * 10:   b9400108        ldr     w8, [x8] <-- trapping instruction
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.
>
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>
> If the report is already addressed, let syzbot know by replying with:
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>
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>
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>
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>
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