On Thu, Jun 20, 2024 at 10:13:24AM -0700, syzbot wrote:

Hello,

syzbot found the following issue on:

HEAD commit:    2ccbdf43d5e7 Merge tag 'for-linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10341146980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fa0ce06dcc735711
dashboard link: https://syzkaller.appspot.com/bug?extid=696cffe71c444e4a2dd8
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13e8bfee980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12d3d851980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/93525a95fe83/disk-2ccbdf43.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b9b895227ea2/vmlinux-2ccbdf43.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e825248a8e73/bzImage-2ccbdf43.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+696cffe71c444e4a2dd8@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { P45
 1-....
 } 2688 jiffies s: 1349 root: 0x2/T
rcu: blocking rcu_node structures (internal RCU debug):

Sending NMI from CPU 0 to CPUs 1:
cdc_wdm 3-1:1.0: wdm_int_callback - 0 bytes
cdc_wdm 3-1:1.0: nonzero urb status received: -71
cdc_wdm 3-1:1.0: wdm_int_callback - 0 bytes
cdc_wdm 3-1:1.0: nonzero urb status received: -71

#syz dup: [syzbot] [usb?] INFO: rcu detected stall in raw_ioctl

Alan Stern