mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-15 00:04:15 +08:00
0070ed3d9e
There is a 16-byte memory leak inside sunrpc/auth_gss on an nfs server when
a client mounts with 'sec=krb5' in a simple mount / umount loop. The leak
is seen by either monitoring the kmalloc-16 slab or with kmemleak enabled
unreferenced object 0xffff92e6a045f030 (size 16):
comm "nfsd", pid 1096, jiffies 4294936658 (age 761.110s)
hex dump (first 16 bytes):
2a 86 48 86 f7 12 01 02 02 00 00 00 00 00 00 00 *.H.............
backtrace:
[<000000004b2b79a7>] gssx_dec_buffer+0x79/0x90 [auth_rpcgss]
[<000000002610ac1a>] gssx_dec_accept_sec_context+0x215/0x6dd [auth_rpcgss]
[<000000004fd0e81d>] rpcauth_unwrap_resp+0xa9/0xe0 [sunrpc]
[<000000002b099233>] call_decode+0x1e9/0x840 [sunrpc]
[<00000000954fc846>] __rpc_execute+0x80/0x3f0 [sunrpc]
[<00000000c83a961c>] rpc_run_task+0x10d/0x150 [sunrpc]
[<000000002c2cdcd2>] rpc_call_sync+0x4d/0xa0 [sunrpc]
[<000000000b74eea2>] gssp_accept_sec_context_upcall+0x196/0x470 [auth_rpcgss]
[<000000003271273f>] svcauth_gss_proxy_init+0x188/0x520 [auth_rpcgss]
[<000000001cf69f01>] svcauth_gss_accept+0x3a6/0xb50 [auth_rpcgss]
If you map the above to code you'll see the following call chain
gssx_dec_accept_sec_context
gssx_dec_ctx (missing from kmemleak output)
gssx_dec_buffer(xdr, &ctx->mech)
Inside gssx_dec_buffer there is 'kmemdup' where we allocate memory for
any gssx_buffer (buf) and store into buf->data. In the above instance,
'buf == &ctx->mech).
Further up in the chain in gssp_accept_sec_context_upcall we see ctx->mech
is part of a stack variable 'struct gssx_ctx rctxh'. Now later inside
gssp_accept_sec_context_upcall after gssp_call, there is a number of
memcpy and kfree statements, but there is no kfree(rctxh.mech.data)
after the memcpy into data->mech_oid.data.
With this patch applied and the same mount / unmount loop, the kmalloc-16
slab is stable and kmemleak enabled no longer shows the above backtrace.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
|
||
|---|---|---|
| .. | ||
| auth_gss | ||
| xprtrdma | ||
| addr.c | ||
| auth_generic.c | ||
| auth_null.c | ||
| auth_unix.c | ||
| auth.c | ||
| backchannel_rqst.c | ||
| cache.c | ||
| clnt.c | ||
| debugfs.c | ||
| Kconfig | ||
| Makefile | ||
| netns.h | ||
| rpc_pipe.c | ||
| rpcb_clnt.c | ||
| sched.c | ||
| socklib.c | ||
| stats.c | ||
| sunrpc_syms.c | ||
| sunrpc.h | ||
| svc_xprt.c | ||
| svc.c | ||
| svcauth_unix.c | ||
| svcauth.c | ||
| svcsock.c | ||
| sysctl.c | ||
| timer.c | ||
| xdr.c | ||
| xprt.c | ||
| xprtmultipath.c | ||
| xprtsock.c | ||