lib/generic-radix-tree.c: add kmemleak annotations (3c52b0af) · Commits · 戴 / test

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>

lib/generic-radix-tree.c

+26 −6

Original line number	Diff line number	Diff line
		@@ -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 @@ void __genradix_ptr(struct __genradix radix, size_t offset)
		}
		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 @@ void __genradix_ptr_alloc(struct __genradix radix, size_t offset,
		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 @@ void __genradix_ptr_alloc(struct __genradix radix, size_t offset,
		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 @@ void __genradix_ptr_alloc(struct __genradix radix, size_t offset,
		}

		if (new_node)
		free_page((unsigned long) new_node);
		genradix_free_node(new_node);

		return &n->data[offset];
		}
		@@ -191,7 +211,7 @@ static void genradix_free_recurse(struct genradix_node *n, unsigned level)
		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,

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