general protection fault in percpu_ref_exit
Status: upstream: reported C repro on 2020/10/08 15:09
Fix commit: 7ea6bf2e percpu_ref: don't refer to ref->data if it isn't allocated
Patched on: [ci-qemu-upstream ci-qemu-upstream-386 ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-leak ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-upstream-kmsan-gce ci-upstream-kmsan-gce-386]
First crash: 18d, last: 14d

Cause bisection: introduced by (bisect log) :
commit 2b0d3d3e4fcfb19d10f9a82910b8f0f05c56ee3e
Author: Ming Lei <>
Date: Thu Oct 1 15:48:41 2020 +0000

  percpu_ref: reduce memory footprint of percpu_ref in fast path

Crash: BUG: unable to handle kernel NULL pointer dereference in __percpu_ref_exit (log)
Repro: C syz .config

Sample crash report:

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Maintainers
ci-upstream-linux-next-kasan-gce-root 2020/10/08 11:18 linux-next 8b787da7 1880b4a9 .config log report syz C,,,,
ci-upstream-linux-next-kasan-gce-root 2020/10/12 09:39 linux-next d67bc781 4a77ae0b .config log report info,,,,
ci-upstream-linux-next-kasan-gce-root 2020/10/08 10:57 linux-next 8b787da7 1880b4a9 .config log report info,,,,