panic: Incrementing non-positive count ADDR on nsfs.Inode

Status: fixed on 2026/05/08 08:36
Fix commit: e0b8f07fefe9 pidfds: Fix setns() race with a dying target pidns
First crash: 121d, last: 121d

Sample crash report:
panic: Incrementing non-positive count 0xc000ef71e8 on nsfs.Inode

goroutine 59355 gp=0xc00074dc00 m=21 mp=0xc0004ef008 [running]:
panic({0x18ccb40?, 0xc000f80f50?})
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/go/src/runtime/panic.go:802 +0x168 fp=0xc0009e98c0 sp=0xc0009e9810 pc=0x480428
gvisor.dev/gvisor/pkg/sentry/fsimpl/nsfs.(*inodeRefs).IncRef(0xc000ef71e8)
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/fsimpl/nsfs/inode_refs.go:82 +0x1c8 fp=0xc0009e9928 sp=0xc0009e98c0 pc=0xb95a88
gvisor.dev/gvisor/pkg/sentry/kernel.(*PIDNamespace).IncRef(...)
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/threads.go:258
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).GetPIDNamespace(...)
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/threads.go:577
gvisor.dev/gvisor/pkg/sentry/kernel.(*namespaceSet).initFromTask(0xc0009e9988, 0xc0ffffffff?, 0xc0018b8588, 0x20000000)
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/task_clone.go:532 +0x179 fp=0xc0009e9950 sp=0xc0009e9928 pc=0xdfc259
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Setns(0xc0011a1908, 0xc000f70c00, 0x20000000)
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/task_clone.go:612 +0x3e6 fp=0xc0009e9a00 sp=0xc0009e9950 pc=0xdfcde6
gvisor.dev/gvisor/pkg/sentry/syscalls/linux.Setns(0xc0011a1908, 0x0?, {{0x4}, {0x20000000}, {0x0}, {0x0}, {0x0}, {0x0}})
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/syscalls/linux/sys_thread.go:479 +0x1a5 fp=0xc0009e9a78 sp=0xc0009e9a00 pc=0x1109425
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).executeSyscall(0xc0011a1908, 0x134, {{0x4}, {0x20000000}, {0x0}, {0x0}, {0x0}, {0x0}})
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/task_syscall.go:143 +0xd10 fp=0xc0009e9ca8 sp=0xc0009e9a78 pc=0xe304f0
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke(0xc0011a1908, 0x134, {{0x4}, {0x20000000}, {0x0}, {0x0}, {0x0}, {0x0}})
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/task_syscall.go:323 +0x7f fp=0xc0009e9d00 sp=0xc0009e9ca8 pc=0xe327df
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter(0xc0011a1908, 0x134, {{0x4}, {0x20000000}, {0x0}, {0x0}, {0x0}, {0x0}})
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/task_syscall.go:283 +0xc5 fp=0xc0009e9d50 sp=0xc0009e9d00 pc=0xe31e65
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).doSyscall(0xc00137a4e0?)
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/task_syscall.go:258 +0x5b2 fp=0xc0009e9e28 sp=0xc0009e9d50 pc=0xe318b2
gvisor.dev/gvisor/pkg/sentry/kernel.(*runApp).execute(0xc00175fc20?, 0xc0011a1908)
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/task_run.go:258 +0x204b fp=0xc0009e9f30 sp=0xc0009e9e28 pc=0xe1deeb
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).run(0xc0011a1908, 0x30d8)
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/task_run.go:89 +0x3de fp=0xc0009e9fc0 sp=0xc0009e9f30 pc=0xe1b71e
gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start.gowrap1()
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/task_start.go:416 +0x25 fp=0xc0009e9fe0 sp=0xc0009e9fc0 pc=0xe2de05
runtime.goexit({})
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/go/src/runtime/asm_amd64.s:1693 +0x1 fp=0xc0009e9fe8 sp=0xc0009e9fe0 pc=0x4896c1
created by gvisor.dev/gvisor/pkg/sentry/kernel.(*Task).Start in goroutine 57418
	/syzkaller/.cache/bazel/_bazel_root/a253eda3fed063e21a974f93b08d3c99/sandbox/linux-sandbox/9/execroot/_main/gopath/src/gvisor.dev/gvisor/pkg/sentry/kernel/task_start.go:416 +0x110

Crashes (20):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/03 07:30 gvisor f395c7e409ad a0d91488 .config console log report syz / log C ci-gvisor-ptrace-1-cover panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:48 gvisor f395c7e409ad a0d91488 console log report syz / log C ci-gvisor-ptrace-2 panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:39 gvisor f395c7e409ad a0d91488 .config console log report syz / log C ci-gvisor-ptrace-2-race-cover panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:36 gvisor f395c7e409ad a0d91488 .config console log report syz / log C ci-gvisor-ptrace-1-race-cover panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:34 gvisor f395c7e409ad a0d91488 .config console log report syz / log C ci-gvisor-systrap-1-race-cover panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:26 gvisor f395c7e409ad a0d91488 console log report syz / log C ci-gvisor-systrap-1 panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:26 gvisor f395c7e409ad a0d91488 .config console log report syz / log C ci-gvisor-systrap-1-cover panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:26 gvisor f395c7e409ad a0d91488 .config console log report syz / log C ci-gvisor-systrap-1-race panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:25 gvisor f395c7e409ad a0d91488 console log report syz / log C ci-gvisor-kvm panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:25 gvisor f395c7e409ad a0d91488 .config console log report syz / log C ci-gvisor-kvm-cover panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:20 gvisor f395c7e409ad a0d91488 console log report syz / log C ci-gvisor-ptrace-1 panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 07:02 gvisor f395c7e409ad 340bcdf0 .config console log report syz / log C ci-gvisor-arm64-systrap-1-race-cover panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:43 gvisor f395c7e409ad 340bcdf0 .config console log report syz / log C ci-gvisor-arm64-systrap-1-race panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:34 gvisor f395c7e409ad 340bcdf0 .config console log report syz / log C ci-gvisor-arm64-ptrace-1-race-cover panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:25 gvisor f395c7e409ad 340bcdf0 console log report syz / log C ci-gvisor-arm64-systrap-1 panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:16 gvisor f395c7e409ad 340bcdf0 .config console log report syz / log C ci-gvisor-arm64-systrap-1-cover panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:16 gvisor f395c7e409ad 340bcdf0 .config console log report syz / log C ci-gvisor-arm64-ptrace-1-cover panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:15 gvisor f395c7e409ad 340bcdf0 console log report syz / log C ci-gvisor-arm64-ptrace-1 panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 06:00 gvisor f395c7e409ad 340bcdf0 .config console log report syz / log C ci-gvisor-arm64-ptrace-1-race panic: Incrementing non-positive count ADDR on nsfs.Inode
2026/05/03 05:28 gvisor f395c7e409ad 340bcdf0 .config console log report info ci-gvisor-arm64-ptrace-1-race panic: Incrementing non-positive count ADDR on nsfs.Inode
* Struck through repros no longer work on HEAD.