Re: memory leak in em_nbyte_change

[Eric Dumazet]

On 1/24/20 2:47 PM, syzbot wrote:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    4703d911 Merge tag 'xarray-5.5' of git://git.infradead.org..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1031e335e00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=15478c61c836a72e
> dashboard link: https://syzkaller.appspot.com/bug?extid=03c4738ed29d5d366ddf
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1277ce01e00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16681611e00000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+03c4738ed29d5d366ddf@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> BUG: memory leak
> unreferenced object 0xffff888121850a40 (size 32):
>   comm "syz-executor927", pid 7193, jiffies 4294941655 (age 19.840s)
>   hex dump (first 32 bytes):
>     00 00 00 00 01 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:
>     [<00000000f67036ea>] kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
>     [<00000000f67036ea>] slab_post_alloc_hook mm/slab.h:586 [inline]
>     [<00000000f67036ea>] slab_alloc mm/slab.c:3320 [inline]
>     [<00000000f67036ea>] __do_kmalloc mm/slab.c:3654 [inline]
>     [<00000000f67036ea>] __kmalloc_track_caller+0x165/0x300 mm/slab.c:3671
>     [<00000000fab0cc8e>] kmemdup+0x27/0x60 mm/util.c:127
>     [<00000000d9992e0a>] kmemdup include/linux/string.h:453 [inline]
>     [<00000000d9992e0a>] em_nbyte_change+0x5b/0x90 net/sched/em_nbyte.c:32
>     [<000000007e04f711>] tcf_em_validate net/sched/ematch.c:241 [inline]
>     [<000000007e04f711>] tcf_em_tree_validate net/sched/ematch.c:359 [inline]
>     [<000000007e04f711>] tcf_em_tree_validate+0x332/0x46f net/sched/ematch.c:300
>     [<000000007a769204>] basic_set_parms net/sched/cls_basic.c:157 [inline]
>     [<000000007a769204>] basic_change+0x1d7/0x5f0 net/sched/cls_basic.c:219
>     [<00000000e57a5997>] tc_new_tfilter+0x566/0xf70 net/sched/cls_api.c:2104
>     [<0000000074b68559>] rtnetlink_rcv_msg+0x3b2/0x4b0 net/core/rtnetlink.c:5415
>     [<00000000b7fe53fb>] netlink_rcv_skb+0x61/0x170 net/netlink/af_netlink.c:2477
>     [<00000000e83a40d0>] rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5442
>     [<00000000d62ba933>] netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
>     [<00000000d62ba933>] netlink_unicast+0x223/0x310 net/netlink/af_netlink.c:1328
>     [<0000000088070f72>] netlink_sendmsg+0x2c0/0x570 net/netlink/af_netlink.c:1917
>     [<00000000f70b15ea>] sock_sendmsg_nosec net/socket.c:639 [inline]
>     [<00000000f70b15ea>] sock_sendmsg+0x54/0x70 net/socket.c:659
>     [<00000000ef95a9be>] ____sys_sendmsg+0x2d0/0x300 net/socket.c:2330
>     [<00000000b650f1ab>] ___sys_sendmsg+0x8a/0xd0 net/socket.c:2384
>     [<0000000055bfa74a>] __sys_sendmsg+0x80/0xf0 net/socket.c:2417
>     [<000000002abac183>] __do_sys_sendmsg net/socket.c:2426 [inline]
>     [<000000002abac183>] __se_sys_sendmsg net/socket.c:2424 [inline]
>     [<000000002abac183>] __x64_sys_sendmsg+0x23/0x30 net/socket.c:2424
> 
> BUG: memory leak
> unreferenced object 0xffff888115438ea0 (size 32):
>   comm "syz-executor927", pid 7194, jiffies 4294942248 (age 13.910s)
>   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:
>     [<00000000f67036ea>] kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
>     [<00000000f67036ea>] slab_post_alloc_hook mm/slab.h:586 [inline]
>     [<00000000f67036ea>] slab_alloc mm/slab.c:3320 [inline]
>     [<00000000f67036ea>] __do_kmalloc mm/slab.c:3654 [inline]
>     [<00000000f67036ea>] __kmalloc_track_caller+0x165/0x300 mm/slab.c:3671
>     [<00000000fab0cc8e>] kmemdup+0x27/0x60 mm/util.c:127
>     [<00000000d9992e0a>] kmemdup include/linux/string.h:453 [inline]
>     [<00000000d9992e0a>] em_nbyte_change+0x5b/0x90 net/sched/em_nbyte.c:32
>     [<000000007e04f711>] tcf_em_validate net/sched/ematch.c:241 [inline]
>     [<000000007e04f711>] tcf_em_tree_validate net/sched/ematch.c:359 [inline]
>     [<000000007e04f711>] tcf_em_tree_validate+0x332/0x46f net/sched/ematch.c:300
>     [<000000007a769204>] basic_set_parms net/sched/cls_basic.c:157 [inline]
>     [<000000007a769204>] basic_change+0x1d7/0x5f0 net/sched/cls_basic.c:219
>     [<00000000e57a5997>] tc_new_tfilter+0x566/0xf70 net/sched/cls_api.c:2104
>     [<0000000074b68559>] rtnetlink_rcv_msg+0x3b2/0x4b0 net/core/rtnetlink.c:5415
>     [<00000000b7fe53fb>] netlink_rcv_skb+0x61/0x170 net/netlink/af_netlink.c:2477
>     [<00000000e83a40d0>] rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5442
>     [<00000000d62ba933>] netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
>     [<00000000d62ba933>] netlink_unicast+0x223/0x310 net/netlink/af_netlink.c:1328
>     [<0000000088070f72>] netlink_sendmsg+0x2c0/0x570 net/netlink/af_netlink.c:1917
>     [<00000000f70b15ea>] sock_sendmsg_nosec net/socket.c:639 [inline]
>     [<00000000f70b15ea>] sock_sendmsg+0x54/0x70 net/socket.c:659
>     [<00000000ef95a9be>] ____sys_sendmsg+0x2d0/0x300 net/socket.c:2330
>     [<00000000b650f1ab>] ___sys_sendmsg+0x8a/0xd0 net/socket.c:2384
>     [<0000000055bfa74a>] __sys_sendmsg+0x80/0xf0 net/socket.c:2417
>     [<000000002abac183>] __do_sys_sendmsg net/socket.c:2426 [inline]
>     [<000000002abac183>] __se_sys_sendmsg net/socket.c:2424 [inline]
>     [<000000002abac183>] __x64_sys_sendmsg+0x23/0x30 net/socket.c:2424
> 
> BUG: memory leak
> unreferenced object 0xffff88811c962180 (size 32):
>   comm "syz-executor927", pid 7195, jiffies 4294942844 (age 7.950s)
>   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:
>     [<00000000f67036ea>] kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
>     [<00000000f67036ea>] slab_post_alloc_hook mm/slab.h:586 [inline]
>     [<00000000f67036ea>] slab_alloc mm/slab.c:3320 [inline]
>     [<00000000f67036ea>] __do_kmalloc mm/slab.c:3654 [inline]
>     [<00000000f67036ea>] __kmalloc_track_caller+0x165/0x300 mm/slab.c:3671
>     [<00000000fab0cc8e>] kmemdup+0x27/0x60 mm/util.c:127
>     [<00000000d9992e0a>] kmemdup include/linux/string.h:453 [inline]
>     [<00000000d9992e0a>] em_nbyte_change+0x5b/0x90 net/sched/em_nbyte.c:32
>     [<000000007e04f711>] tcf_em_validate net/sched/ematch.c:241 [inline]
>     [<000000007e04f711>] tcf_em_tree_validate net/sched/ematch.c:359 [inline]
>     [<000000007e04f711>] tcf_em_tree_validate+0x332/0x46f net/sched/ematch.c:300
>     [<000000007a769204>] basic_set_parms net/sched/cls_basic.c:157 [inline]
>     [<000000007a769204>] basic_change+0x1d7/0x5f0 net/sched/cls_basic.c:219
>     [<00000000e57a5997>] tc_new_tfilter+0x566/0xf70 net/sched/cls_api.c:2104
>     [<0000000074b68559>] rtnetlink_rcv_msg+0x3b2/0x4b0 net/core/rtnetlink.c:5415
>     [<00000000b7fe53fb>] netlink_rcv_skb+0x61/0x170 net/netlink/af_netlink.c:2477
>     [<00000000e83a40d0>] rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5442
>     [<00000000d62ba933>] netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
>     [<00000000d62ba933>] netlink_unicast+0x223/0x310 net/netlink/af_netlink.c:1328
>     [<0000000088070f72>] netlink_sendmsg+0x2c0/0x570 net/netlink/af_netlink.c:1917
>     [<00000000f70b15ea>] sock_sendmsg_nosec net/socket.c:639 [inline]
>     [<00000000f70b15ea>] sock_sendmsg+0x54/0x70 net/socket.c:659
>     [<00000000ef95a9be>] ____sys_sendmsg+0x2d0/0x300 net/socket.c:2330
>     [<00000000b650f1ab>] ___sys_sendmsg+0x8a/0xd0 net/socket.c:2384
>     [<0000000055bfa74a>] __sys_sendmsg+0x80/0xf0 net/socket.c:2417
>     [<000000002abac183>] __do_sys_sendmsg net/socket.c:2426 [inline]
>     [<000000002abac183>] __se_sys_sendmsg net/socket.c:2424 [inline]
>     [<000000002abac183>] __x64_sys_sendmsg+0x23/0x30 net/socket.c:2424
> 
> 
> 
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx
> 
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> syzbot can test patches for this bug, for details see:
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> 

Fixed in https://patchwork.ozlabs.org/patch/1229100/