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On Mon, 10 Sep 2007 15:13:19 -0700 (PDT) menage@google.com (Paul Menage) wrote: > Add a BUG_ON() to check for passing an unreferenced dentry to dput(). > > This is analogous to the similar check in dget(), and will make > reference-counting bugs in filesystems more immediately obvious. (I > just spent a while debugging an oops that turned out to be due to > broken fs reference counting.) > > Signed-off-by: Paul Menage <menage@google.com> > > --- > fs/dcache.c | 1 + > 1 file changed, 1 insertion(+) > > Index: container-2.6.23-rc3-mm1/fs/dcache.c > =================================================================== > --- container-2.6.23-rc3-mm1.orig/fs/dcache.c > +++ container-2.6.23-rc3-mm1/fs/dcache.c > @@ -176,6 +176,7 @@ void dput(struct dentry *dentry) > if (!dentry) > return; > > + BUG_ON(!atomic_read(&dentry->d_count)); > repeat: > if (atomic_read(&dentry->d_count) == 1) > might_sleep(); eek, much too aggressive. I added this: --- a/fs/dcache.c~add-a-refcount-check-in-dput +++ a/fs/dcache.c @@ -176,6 +176,7 @@ void dput(struct dentry *dentry) if (!dentry) return; + WARN_ON_ONCE(!atomic_read(&dentry->d_count)); repeat: if (atomic_read(&dentry->d_count) == 1) might_sleep(); _ to the -mm-only-debugging-patches section of the -mm tree. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||
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