Re: net: memory leak in mkiss_open

[Cong Wang]

On Mon, Feb 22, 2016 at 2:05 AM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
> unreferenced object 0xffff8800628991d8 (size 4096):
>   comm "a.out", pid 7081, jiffies 4294920662 (age 35.917s)
>   hex dump (first 32 bytes):
>     00 00 00 00 00 00 00 00 61 78 30 00 00 00 00 00  ........ax0.....
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff86680923>] kmemleak_alloc+0x63/0xa0 mm/kmemleak.c:916
>     [<     inline     >] kmemleak_alloc_recursive include/linux/kmemleak.h:47
>     [<     inline     >] slab_post_alloc_hook mm/slub.c:1337
>     [<     inline     >] slab_alloc_node mm/slub.c:2596
>     [<     inline     >] slab_alloc mm/slub.c:2604
>     [<ffffffff8176b585>] __kmalloc+0x1c5/0x3a0 mm/slub.c:3564
>     [<     inline     >] kmalloc include/linux/slab.h:468
>     [<ffffffff8554c93e>] kzalloc+0x1e/0x30 include/linux/slab.h:607
>     [<ffffffff85551442>] alloc_netdev_mqs+0x82/0xd20 net/core/dev.c:7387
>     [<ffffffff83ef39da>] mkiss_open+0xaa/0xc30 drivers/net/hamradio/mkiss.c:707
>     [<ffffffff82fbd258>] tty_ldisc_open.isra.2+0x78/0xd0
> drivers/tty/tty_ldisc.c:454
>     [<ffffffff82fbd842>] tty_set_ldisc+0x292/0x8a0 drivers/tty/tty_ldisc.c:561
>     [<     inline     >] tiocsetd drivers/tty/tty_io.c:2655
>     [<ffffffff82fa651e>] tty_ioctl+0xb2e/0x2160 drivers/tty/tty_io.c:2910
>     [<     inline     >] vfs_ioctl fs/ioctl.c:43
>     [<ffffffff8180597c>] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
>     [<     inline     >] SYSC_ioctl fs/ioctl.c:689
>     [<ffffffff8180682f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
>     [<ffffffff8669ddb6>] entry_SYSCALL_64_fastpath+0x16/0x7a
> arch/x86/entry/entry_64.S:185
>     [<ffffffffffffffff>] 0xffffffffffffffff
> unreferenced object 0xffff8800652b1aa0 (size 96):
>   comm "a.out", pid 7081, jiffies 4294920662 (age 35.917s)
>   hex dump (first 32 bytes):
>     b8 94 89 62 00 88 ff ff b8 94 89 62 00 88 ff ff  ...b.......b....
>     98 92 9c aa b0 40 02 00 00 00 00 00 00 00 00 00  .....@..........
>   backtrace:
>     [<ffffffff86680923>] kmemleak_alloc+0x63/0xa0 mm/kmemleak.c:916
>     [<     inline     >] kmemleak_alloc_recursive include/linux/kmemleak.h:47
>     [<     inline     >] slab_post_alloc_hook mm/slub.c:1337
>     [<     inline     >] slab_alloc_node mm/slub.c:2596
>     [<     inline     >] slab_alloc mm/slub.c:2604
>     [<ffffffff8176ae6e>] kmem_cache_alloc_trace+0x1ee/0x350 mm/slub.c:2621
>     [<     inline     >] kmalloc include/linux/slab.h:463
>     [<ffffffff8557a4e2>] __hw_addr_create_ex+0x62/0x240
> net/core/dev_addr_lists.c:34
>     [<ffffffff8557a7bc>] __hw_addr_add_ex+0xfc/0x270
> net/core/dev_addr_lists.c:80
>     [<     inline     >] __hw_addr_add net/core/dev_addr_lists.c:88
>     [<ffffffff8557ac35>] dev_addr_init+0x105/0x1c0 net/core/dev_addr_lists.c:371
>     [<ffffffff855514f0>] alloc_netdev_mqs+0x130/0xd20 net/core/dev.c:7400
>     [<ffffffff83ef39da>] mkiss_open+0xaa/0xc30 drivers/net/hamradio/mkiss.c:707
>     [<ffffffff82fbd258>] tty_ldisc_open.isra.2+0x78/0xd0
> drivers/tty/tty_ldisc.c:454
>     [<ffffffff82fbd842>] tty_set_ldisc+0x292/0x8a0 drivers/tty/tty_ldisc.c:561
>     [<     inline     >] tiocsetd drivers/tty/tty_io.c:2655
>     [<ffffffff82fa651e>] tty_ioctl+0xb2e/0x2160 drivers/tty/tty_io.c:2910
>     [<     inline     >] vfs_ioctl fs/ioctl.c:43
>     [<ffffffff8180597c>] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674
>     [<     inline     >] SYSC_ioctl fs/ioctl.c:689
>     [<ffffffff8180682f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680
>     [<ffffffff8669ddb6>] entry_SYSCALL_64_fastpath+0x16/0x7a
> arch/x86/entry/entry_64.S:185

This looks more like a tty layer leak than netdev layer.