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Fri, 04 Oct 2019 05:21:23 -0700 (PDT) Received: by localhost.localdomain (Postfix, from userid 1000) id A464AC07B9; Fri, 4 Oct 2019 09:21:20 -0300 (-03) Date: Fri, 4 Oct 2019 09:21:20 -0300 From: Marcelo Ricardo Leitner To: Eric Biggers Cc: Andrew Morton , 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 Subject: Re: [PATCH] lib/generic-radix-tree.c: add kmemleak annotations Message-ID: <20191004122120.GP3431@localhost.localdomain> References: <20191004065039.727564-1-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191004065039.727564-1-ebiggers@kernel.org> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 03, 2019 at 11:50:39PM -0700, Eric Biggers wrote: > 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. Nice, thanks Eric. Reviewed-by: Marcelo Ricardo Leitner > > Reported-by: syzbot+7f3b6b106be8dcdcdeec@syzkaller.appspotmail.com > Signed-off-by: Eric Biggers > --- > 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, > -- > 2.23.0 > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Ricardo Leitner Date: Fri, 04 Oct 2019 12:21:20 +0000 Subject: Re: [PATCH] lib/generic-radix-tree.c: add kmemleak annotations Message-Id: <20191004122120.GP3431@localhost.localdomain> List-Id: References: <20191004065039.727564-1-ebiggers@kernel.org> In-Reply-To: <20191004065039.727564-1-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Eric Biggers Cc: Andrew Morton , 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 On Thu, Oct 03, 2019 at 11:50:39PM -0700, Eric Biggers wrote: > 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. Nice, thanks Eric. Reviewed-by: Marcelo Ricardo Leitner > > Reported-by: syzbot+7f3b6b106be8dcdcdeec@syzkaller.appspotmail.com > Signed-off-by: Eric Biggers > --- > 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, > -- > 2.23.0 >