Date: Tue, 22 Apr 2014 16:21:43 +0900 From: takehara.mikihito@jp.panasonic.com To: freebsd-current@freebsd.org Subject: uninitialized journal data written in SU+J ? Message-ID: <C1CF5DFB8355ACtakehara.mikihito@jp.panasonic.com>
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Hello,
I'm testing UFS with SU+J. But it seems sometimes broken journal data has written.
In softdep_process_journal (ffs_softdep.c), there is a while code to build jsegrec and each entry.
But by my test, sometimes there is no entry then break this while code without building jsegrec.
If this happens, bp->b_data is not initialized but this bp is written, I think.
I checked this behavior by following patch.
============================================================================================
diff --git a/sys/ufs/ffs/ffs_softdep.c b/sys/ufs/ffs/ffs_softdep.c
index 585af50..2d4939c 100644
--- a/sys/ufs/ffs/ffs_softdep.c
+++ b/sys/ufs/ffs/ffs_softdep.c
@@ -3421,6 +3421,15 @@ softdep_process_journal(mp, needwk, flags)
data = bp->b_data + off;
cnt--;
}
+
+#if 1
+ if (off == 0) {
+ struct jsegrec *tmp = (struct jsegrec*)bp->b_data;
+ if (tmp->jsr_seq != jseg->js_seq) {
+ panic("test test");
+ }
+ }
+#endif
/*
* Write this one buffer and continue.
*/
============================================================================================
If uninitialized data is "valid" by fsck suj, this may result filesystem corruption, I think.
I think it's better to clear b_data before using it.
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