sanitize uninitialized values

bcachefs fsck reports a lot of unitialized values, which is a bad thing. before the kernel sources are fixed, a temporary workaround is to clear a number of allocations, to avoid unexpected results. This patch improves stabilization, but has a severe performance impact Signed-off-by: Janpieter Sollie <[email protected]>
jpsollie · Jul 22, 2024 · 1fb9b67 · 1fb9b67
1 parent 60ff4f2
commit 1fb9b67
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diff --git a/libbcachefs/btree_cache.c b/libbcachefs/btree_cache.c
@@ -103,6 +103,9 @@ static int btree_node_data_alloc(struct bch_fs *c, struct btree *b, gfp_t gfp)
 	BUG_ON(b->data || b->aux_data);
 
 	b->data = kvmalloc(btree_buf_bytes(b), gfp);
+#ifdef CLEAR_PAGES_IN_ADVANCE
+	memset(b->data, 0, btree_buf_bytes(b));
+#endif
 	if (!b->data)
 		return -BCH_ERR_ENOMEM_btree_node_mem_alloc;
 #ifdef __KERNEL__

diff --git a/libbcachefs/btree_io.c b/libbcachefs/btree_io.c
@@ -122,6 +122,9 @@ static void *btree_bounce_alloc(struct bch_fs *c, size_t size,
 
 	*used_mempool = false;
 	p = kvmalloc(size, __GFP_NOWARN|GFP_NOWAIT);
+#ifdef CLEAR_PAGES_IN_ADVANCE
+        memset(p, 0, size);
+#endif
 	if (!p) {
 		*used_mempool = true;
 		p = mempool_alloc(&c->btree_bounce_pool, GFP_NOFS);

diff --git a/libbcachefs/trace.h b/libbcachefs/trace.h
@@ -2,6 +2,10 @@
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM bcachefs
 
+#ifndef CLEAR_PAGES_IN_ADVANCE
+#define CLEAR_PAGES_IN_ADVANCE 1
+#endif
+
 #if !defined(_TRACE_BCACHEFS_H) || defined(TRACE_HEADER_MULTI_READ)
 
 #include <linux/tracepoint.h>