lib/generic-radix-tree.c: add kmemleak annotations
Kmemleak is falsely reporting a leak of the slab allocation in
sctp_stream_init_ext():
BUG: memory leak
unreferenced object 0xffff8881114f5d80 (size 96):
comm "syz-executor934", pid 7160, jiffies 4294993058 (age 31.950s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000ce7a1326>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
[<00000000ce7a1326>] slab_post_alloc_hook mm/slab.h:439 [inline]
[<00000000ce7a1326>] slab_alloc mm/slab.c:3326 [inline]
[<00000000ce7a1326>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
[<000000007abb7ac9>] kmalloc include/linux/slab.h:547 [inline]
[<000000007abb7ac9>] kzalloc include/linux/slab.h:742 [inline]
[<000000007abb7ac9>] sctp_stream_init_ext+0x2b/0xa0 net/sctp/stream.c:157
[<0000000048ecb9c1>] sctp_sendmsg_to_asoc+0x946/0xa00 net/sctp/socket.c:1882
[<000000004483ca2b>] sctp_sendmsg+0x2a8/0x990 net/sctp/socket.c:2102
[...]
But it's freed later. Kmemleak misses the allocation because its
pointer is stored in the generic radix tree sctp_stream::out, and the
generic radix tree uses raw pages which aren't tracked by kmemleak.
Fix this by adding the kmemleak hooks to the generic radix tree code.
Link: http://lkml.kernel.org/r/20191004065039.727564-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reported-by: <syzbot+7f3b6b106be8dcdcdeec@syzkaller.appspotmail.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/generic-radix-tree.c b/lib/generic-radix-tree.c
index ae25e2f..f25eb11 100644
--- a/lib/generic-radix-tree.c
+++ b/lib/generic-radix-tree.c
@@ -2,6 +2,7 @@
#include <linux/export.h>
#include <linux/generic-radix-tree.h>
#include <linux/gfp.h>
+#include <linux/kmemleak.h>
#define GENRADIX_ARY (PAGE_SIZE / sizeof(struct genradix_node *))
#define GENRADIX_ARY_SHIFT ilog2(GENRADIX_ARY)
@@ -75,6 +76,27 @@
}
EXPORT_SYMBOL(__genradix_ptr);
+static inline struct genradix_node *genradix_alloc_node(gfp_t gfp_mask)
+{
+ struct genradix_node *node;
+
+ node = (struct genradix_node *)__get_free_page(gfp_mask|__GFP_ZERO);
+
+ /*
+ * We're using pages (not slab allocations) directly for kernel data
+ * structures, so we need to explicitly inform kmemleak of them in order
+ * to avoid false positive memory leak reports.
+ */
+ kmemleak_alloc(node, PAGE_SIZE, 1, gfp_mask);
+ return node;
+}
+
+static inline void genradix_free_node(struct genradix_node *node)
+{
+ kmemleak_free(node);
+ free_page((unsigned long)node);
+}
+
/*
* Returns pointer to the specified byte @offset within @radix, allocating it if
* necessary - newly allocated slots are always zeroed out:
@@ -97,8 +119,7 @@
break;
if (!new_node) {
- new_node = (void *)
- __get_free_page(gfp_mask|__GFP_ZERO);
+ new_node = genradix_alloc_node(gfp_mask);
if (!new_node)
return NULL;
}
@@ -121,8 +142,7 @@
n = READ_ONCE(*p);
if (!n) {
if (!new_node) {
- new_node = (void *)
- __get_free_page(gfp_mask|__GFP_ZERO);
+ new_node = genradix_alloc_node(gfp_mask);
if (!new_node)
return NULL;
}
@@ -133,7 +153,7 @@
}
if (new_node)
- free_page((unsigned long) new_node);
+ genradix_free_node(new_node);
return &n->data[offset];
}
@@ -191,7 +211,7 @@
genradix_free_recurse(n->children[i], level - 1);
}
- free_page((unsigned long) n);
+ genradix_free_node(n);
}
int __genradix_prealloc(struct __genradix *radix, size_t size,
