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Fri, 4 Oct 2019 06:52:50 +0000 (UTC) Received: from sol.localdomain (c-24-5-143-220.hsd1.ca.comcast.net [24.5.143.220]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CEB2E20862; Fri, 4 Oct 2019 06:52:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570171969; bh=KjLCSWbNFxhPI0um9Zf+8VBwxs6pN5wnIQdyYL09PKs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S2fe1c982Qfk2EPIEelIL45x8L+g2a5shLEP1fdVNxHEsYBk3NHOeNIAlwe1oq6rP tuCAwhCBbBvY3bFadYh6ADBrOSLn3yP3xix97xY4a/R45OXU9mj+6/AlLUUQ+MdPKZ OAeM6mBxfMBTegWjQxadbXj5XVYjTJhymJYz59J4= From: Eric Biggers To: Andrew Morton Cc: linux-mm@kvack.org, linux-sctp@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, Catalin Marinas , Kent Overstreet , Vlad Yasevich , Xin Long , Neil Horman , Marcelo Ricardo Leitner Subject: [PATCH] lib/generic-radix-tree.c: add kmemleak annotations Date: Thu, 3 Oct 2019 23:50:39 -0700 Message-Id: <20191004065039.727564-1-ebiggers@kernel.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: References: MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Eric Biggers 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. Reported-by: syzbot+7f3b6b106be8dcdcdeec@syzkaller.appspotmail.com Signed-off-by: Eric Biggers Reviewed-by: Marcelo Ricardo Leitner Acked-by: Neil Horman Reviewed-by: Catalin Marinas --- lib/generic-radix-tree.c | 32 ++++++++++++++++++++++++++------ 1 file changed, 26 insertions(+), 6 deletions(-) diff --git a/lib/generic-radix-tree.c b/lib/generic-radix-tree.c index ae25e2fa2187..f25eb111c051 100644 --- a/lib/generic-radix-tree.c +++ b/lib/generic-radix-tree.c @@ -2,6 +2,7 @@ #include #include #include +#include #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,