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SubjectRe: [PATCH] lib/generic-radix-tree.c: add kmemleak annotations
On Thu, Oct 03, 2019 at 11:50:39PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> 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 <ebiggers@google.com>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

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