CVE-2022-49928

In the Linux kernel, the following vulnerability has been resolved:

SUNRPC: Fix null-ptr-deref when xps sysfs alloc failed

There is a null-ptr-deref when xps sysfs alloc failed:

BUG: KASAN: null-ptr-deref in sysfs_do_create_link_sd+0x40/0xd0

Read of size 8 at addr 0000000000000030 by task gssproxy/457

CPU: 5 PID: 457 Comm: gssproxy Not tainted 6.0.0-09040-g02357b27ee03 #9

Call Trace:

<TASK>

dump_stack_lvl+0x34/0x44

kasan_report+0xa3/0x120

sysfs_do_create_link_sd+0x40/0xd0

rpc_sysfs_client_setup+0x161/0x1b0

rpc_new_client+0x3fc/0x6e0

rpc_create_xprt+0x71/0x220

rpc_create+0x1d4/0x350

gssp_rpc_create+0xc3/0x160

set_gssp_clnt+0xbc/0x140

write_gssp+0x116/0x1a0

proc_reg_write+0xd6/0x130

vfs_write+0x177/0x690

ksys_write+0xb9/0x150

do_syscall_64+0x35/0x80

entry_SYSCALL_64_after_hwframe+0x46/0xb0

When the xprt_switch sysfs alloc failed, should not add xprt and

switch sysfs to it, otherwise, maybe null-ptr-deref; also initialize

the 'xps_sysfs' to NULL to avoid oops when destroy it.