diff options
| author | Fabricio Voznika <fvoznika@google.com> | 2021-07-12 18:27:59 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2021-07-12 18:30:46 -0700 |
| commit | 520795aaad701854e9ffe84de1108954cf2b77f8 (patch) | |
| tree | 9f2aa17263053f5fd3edd7614679341202129c08 /pkg/sentry/fsimpl/proc/task.go | |
| parent | 275932bf0852431b6f307ba9c45f26073d20ac62 (diff) | |
Fix deadlock in procfs
Kernfs provides an internal mechanism to defer calls to `DecRef()` because
on the last reference `Filesystem.mu` must be held and most places that
need to call `DecRef()` are inside the lock. The same can be true for
filesystems that extend kernfs. procfs needs to look up files and `DecRef()`
them inside the `kernfs.Filesystem.mu`. If the files happen to be procfs
files, it can deadlock trying to decrement if it's the last reference.
This change extends the mechanism to external callers to defer DecRefs
to `vfs.FileDescription` and `vfs.VirtualDentries`.
PiperOrigin-RevId: 384361647
Diffstat (limited to 'pkg/sentry/fsimpl/proc/task.go')
| -rw-r--r-- | pkg/sentry/fsimpl/proc/task.go | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/pkg/sentry/fsimpl/proc/task.go b/pkg/sentry/fsimpl/proc/task.go index 2717e1359..cbbc0935a 100644 --- a/pkg/sentry/fsimpl/proc/task.go +++ b/pkg/sentry/fsimpl/proc/task.go @@ -65,8 +65,8 @@ func (fs *filesystem) newTaskInode(ctx context.Context, task *kernel.Task, pidns "io": fs.newTaskOwnedInode(ctx, task, fs.NextIno(), 0400, newIO(task, isThreadGroup)), "maps": fs.newTaskOwnedInode(ctx, task, fs.NextIno(), 0444, &mapsData{task: task}), "mem": fs.newMemInode(ctx, task, fs.NextIno(), 0400), - "mountinfo": fs.newTaskOwnedInode(ctx, task, fs.NextIno(), 0444, &mountInfoData{task: task}), - "mounts": fs.newTaskOwnedInode(ctx, task, fs.NextIno(), 0444, &mountsData{task: task}), + "mountinfo": fs.newTaskOwnedInode(ctx, task, fs.NextIno(), 0444, &mountInfoData{fs: fs, task: task}), + "mounts": fs.newTaskOwnedInode(ctx, task, fs.NextIno(), 0444, &mountsData{fs: fs, task: task}), "net": fs.newTaskNetDir(ctx, task), "ns": fs.newTaskOwnedDir(ctx, task, fs.NextIno(), 0511, map[string]kernfs.Inode{ "net": fs.newNamespaceSymlink(ctx, task, fs.NextIno(), "net"), |