diff options
| author | Fabricio Voznika <fvoznika@google.com> | 2021-05-03 13:47:45 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2021-05-03 13:50:37 -0700 |
| commit | 1947c873423cabcaf5e67b667542421ade7414ff (patch) | |
| tree | b54dd4f68aa20b95367594b8941fcca4cb766636 /pkg/sentry/fsimpl/kernfs/kernfs.go | |
| parent | 7cafac9f42a8355e7192b57fcc8d41e31d836c53 (diff) | |
Fix deadlock in /proc/[pid]/fd/[num]
In order to resolve path names, fsSymlink.Readlink() may need to reenter
kernfs. Change the code so that kernfs.Inode.Readlink() is called without
locks and document the new contract.
PiperOrigin-RevId: 371770222
Diffstat (limited to 'pkg/sentry/fsimpl/kernfs/kernfs.go')
| -rw-r--r-- | pkg/sentry/fsimpl/kernfs/kernfs.go | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go index 16486eeae..6f699c9cd 100644 --- a/pkg/sentry/fsimpl/kernfs/kernfs.go +++ b/pkg/sentry/fsimpl/kernfs/kernfs.go @@ -534,6 +534,9 @@ func (d *Dentry) FSLocalPath() string { // - Checking that dentries passed to methods are of the appropriate file type. // - Checking permissions. // +// Inode functions may be called holding filesystem wide locks and are not +// allowed to call vfs functions that may reenter, unless otherwise noted. +// // Specific responsibilities of implementations are documented below. type Inode interface { // Methods related to reference counting. A generic implementation is @@ -680,6 +683,9 @@ type inodeDirectory interface { type inodeSymlink interface { // Readlink returns the target of a symbolic link. If an inode is not a // symlink, the implementation should return EINVAL. + // + // Readlink is called with no kernfs locks held, so it may reenter if needed + // to resolve symlink targets. Readlink(ctx context.Context, mnt *vfs.Mount) (string, error) // Getlink returns the target of a symbolic link, as used by path |