New: PPP async spin_lock_bh badness

http://bugme.osdl.org/show_bug.cgi?id=837

Summary: PPP async spin_lock_bh badness
Kernel Version: 2.5.72
Status: NEW
Severity: normal
Owner: [email protected]
Submitter: [email protected]

Distribution: Redhat 8.0
Hardware Environment: 1 CPU PIII
Software Environment:
Problem Description: PPP async driver locking issue

Steps to reproduce:
* Run user mode PPP over Ethernet which runs PPP over pseudo-tty.

* Get warning:
Badness in local_bh_enable at kernel/softirq.c:109

Call Trace:
 [<c011bb5e>] local_bh_enable+0x7e/0x80
 [<f8a5bc00>] ppp_async_push+0x90/0x180 [ppp_async]
 [<c0126a38>] rcu_process_callbacks+0xc8/0xf0
 [<f8a5b521>] ppp_asynctty_wakeup+0x31/0x60 [ppp_async]
 [<c01ca8d7>] pty_unthrottle+0x57/0x60
 [<c01c74ec>] check_unthrottle+0x3c/0x40
 [<c01c7564>] n_tty_flush_buffer+0x14/0x60
 [<c01cac86>] pty_flush_buffer+0x66/0x70
 [<c01c40f7>] do_tty_hangup+0x3b7/0x410
 [<c01c54dd>] release_dev+0x67d/0x6c0
 [<c0138c4e>] zap_pmd_range+0x4e/0x70
 [<c0138cbe>] unmap_page_range+0x4e/0x80
 [<c01c5891>] tty_release+0x11/0x20
 [<c0147c8e>] __fput+0xee/0x100
 [<c01464db>] filp_close+0x4b/0x80
 [<c01197ac>] put_files_struct+0x7c/0xf0
 [<c011a296>] do_exit+0x116/0x330
 [<c011a4e5>] sys_exit+0x15/0x20
 [<c01092df>] syscall_call+0x7/0xb