From 3c52b0af059e11a063970aed1ad143b9284a79c7 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 14 Oct 2019 14:11:54 -0700 Subject: [PATCH] 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 Reported-by: Reviewed-by: Marcelo Ricardo Leitner Acked-by: Neil Horman Reviewed-by: Catalin Marinas Cc: Kent Overstreet Cc: Vlad Yasevich Cc: Xin Long Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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,