On Tue, Jun 18, 2019 at 11:07:36PM +0300, Julian Anastasov wrote:
> syzkaller reports for memory leak in start_sync_thread [1]
>
> As Eric points out, kthread may start and stop before the
> threadfn function is called, so there is no chance the
> data (tinfo in our case) to be released in thread.
>
> Fix this by releasing tinfo in the controlling code instead.
>
> [1]
> BUG: memory leak
> unreferenced object 0xffff8881206bf700 (size 32):
> comm "syz-executor761", pid 7268, jiffies 4294943441 (age 20.470s)
> hex dump (first 32 bytes):
> 00 40 7c 09 81 88 ff ff 80 45 b8 21 81 88 ff ff .@|......E.!....
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<0000000057619e23>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
> [<0000000057619e23>] slab_post_alloc_hook mm/slab.h:439 [inline]
> [<0000000057619e23>] slab_alloc mm/slab.c:3326 [inline]
> [<0000000057619e23>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
> [<0000000086ce5479>] kmalloc include/linux/slab.h:547 [inline]
> [<0000000086ce5479>] start_sync_thread+0x5d2/0xe10 net/netfilter/ipvs/ip_vs_sync.c:1862
> [<000000001a9229cc>] do_ip_vs_set_ctl+0x4c5/0x780 net/netfilter/ipvs/ip_vs_ctl.c:2402
> [<00000000ece457c8>] nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
> [<00000000ece457c8>] nf_setsockopt+0x4c/0x80 net/netfilter/nf_sockopt.c:115
> [<00000000942f62d4>] ip_setsockopt net/ipv4/ip_sockglue.c:1258 [inline]
> [<00000000942f62d4>] ip_setsockopt+0x9b/0xb0 net/ipv4/ip_sockglue.c:1238
> [<00000000a56a8ffd>] udp_setsockopt+0x4e/0x90 net/ipv4/udp.c:2616
> [<00000000fa895401>] sock_common_setsockopt+0x38/0x50 net/core/sock.c:3130
> [<0000000095eef4cf>] __sys_setsockopt+0x98/0x120 net/socket.c:2078
> [<000000009747cf88>] __do_sys_setsockopt net/socket.c:2089 [inline]
> [<000000009747cf88>] __se_sys_setsockopt net/socket.c:2086 [inline]
> [<000000009747cf88>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086
> [<00000000ded8ba80>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:301
> [<00000000893b4ac8>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> Reported-by: syzbot+7e2e50c8adfccd2e5041@xxxxxxxxxxxxxxxxxxxxxxxxx
> Suggested-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> Fixes: 998e7a76804b ("ipvs: Use kthread_run() instead of doing a double-fork via kernel_thread()")
> Signed-off-by: Julian Anastasov <ja@xxxxxx>
Thanks Julian.
Pablo, please consider this for inclusion in nf.
Acked-by: Simon Horman <horms@xxxxxxxxxxxx>
