From 6451aa1559ce5a135f599682ab33721e116925bd Mon Sep 17 00:00:00 2001 From: Sebastiaan van Stijn Date: Fri, 29 Jan 2021 14:55:08 +0100 Subject: [PATCH 7/7] bsc1200022: fifo.Close(): prevent possible panic if fifo is nil I'm not sure if this is the right approach, and synchronisation should probably be added elsewhere to fix the underlying issue. Trying to prevent a panic that was seen on container restore in th docker daemon: panic: runtime error: invalid memory address or nil pointer dereference [signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x5586c892a7a4] goroutine 420 [running]: github.com/docker/docker/vendor/github.com/containerd/fifo.(*fifo).Close(0x0, 0x0, 0x0) /go/src/github.com/docker/docker/vendor/github.com/containerd/fifo/fifo.go:208 +0x44 github.com/docker/docker/vendor/github.com/containerd/containerd/cio.(*cio).Close(0xc000d06f60, 0x5586cb5654d0, 0xc000d8e9e8) /go/src/github.com/docker/docker/vendor/github.com/containerd/containerd/cio/io.go:203 +0x90 github.com/docker/docker/libcontainerd/remote.(*client).Restore.func1(0xc0008bf820, 0xc0008a2040) /go/src/github.com/docker/docker/libcontainerd/remote/client.go:86 +0x5a github.com/docker/docker/libcontainerd/remote.(*client).Restore(0xc00098e5b0, 0x5586cb61c7c0, 0xc000052088, 0xc0011b6500, 0x40, 0xc0008bf810, 0x5586cb05cf00, 0xffffffffffffffff, 0x0, 0x0, ...) /go/src/github.com/docker/docker/libcontainerd/remote/client.go:107 +0x923 github.com/docker/docker/daemon.(*Daemon).restore.func3(0xc00079d9e0, 0xc000a38230, 0xc00000c1e0, 0xc00079d9a8, 0xc000d84f00, 0xc000d84ed0, 0xc000d84ea0, 0xc00128a280) /go/src/github.com/docker/docker/daemon/daemon.go:351 +0x48a created by github.com/docker/docker/daemon.(*Daemon).restore /go/src/github.com/docker/docker/daemon/daemon.go:319 +0x4b3 If the fifo is nil, there's nothing to be done in Close(), so returning early in that situation. Backport: SUSE-Bugs: bsc#1200022 Signed-off-by: Sebastiaan van Stijn --- vendor/github.com/containerd/fifo/fifo.go | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/vendor/github.com/containerd/fifo/fifo.go b/vendor/github.com/containerd/fifo/fifo.go index 96c214f270bf..c3eec295b578 100644 --- a/vendor/github.com/containerd/fifo/fifo.go +++ b/vendor/github.com/containerd/fifo/fifo.go @@ -204,6 +204,10 @@ func (f *fifo) Write(b []byte) (int, error) { // before open(2) has returned and fifo was never opened. func (f *fifo) Close() (retErr error) { for { + if f == nil { + return + } + select { case <-f.closed: f.handle.Close() -- 2.38.1