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| author | Fabricio Voznika <fvoznika@google.com> | 2021-01-29 12:16:55 -0800 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2021-01-29 12:18:42 -0800 |
| commit | 0fa534f1164f2bf6cf50a37d4dce584b6fc8ec07 (patch) | |
| tree | de6f046c67076a88448faa221bf4e3aad2308ae5 | |
| parent | 25284ae3c9b5f8d96686ba5b18b53819a961d34d (diff) | |
Fix deadlock in specialFileFD.pwrite
When file is regular and metadata cache is authoritative, metadata lock
is taken. The code deadlocks trying to acquire the metadata lock
again to update time stampts.
PiperOrigin-RevId: 354584594
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/special_file.go | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/pkg/sentry/fsimpl/gofer/special_file.go b/pkg/sentry/fsimpl/gofer/special_file.go index 089955a96..ae972fcb5 100644 --- a/pkg/sentry/fsimpl/gofer/special_file.go +++ b/pkg/sentry/fsimpl/gofer/special_file.go @@ -299,10 +299,15 @@ func (fd *specialFileFD) pwrite(ctx context.Context, src usermem.IOSequence, off src = src.TakeFirst64(limit) } - // Do a buffered write. See rationale in PRead. if d.cachedMetadataAuthoritative() { - d.touchCMtime() + if fd.isRegularFile { + d.touchCMtimeLocked() + } else { + d.touchCMtime() + } } + + // Do a buffered write. See rationale in PRead. buf := make([]byte, src.NumBytes()) copied, copyErr := src.CopyIn(ctx, buf) if copied == 0 && copyErr != nil { |