Re: PPP not working on test6-mm2

[Andrew Morton <akpm@osdl.org>]

Jan Ischebeck <mail@jan-ischebeck.de> wrote:
>
> Hi Andrew,
> 
> PPP isn't working anymore since test5-mm1.
> 
> Here a stacktrace from test6-mm2, last lines from dmesg:
> 
> Badness in local_bh_enable at kernel/softirq.c:119
> Call Trace:
> [<c01281e5>] local_bh_enable+0x85/0x90
> [<c0243762>] ppp_async_push+0xa2/0x190
> [<c024307d>] ppp_asynctty_wakeup+0x2d/0x60
> [<c020fcf8>] pty_unthrottle+0x58/0x60
> [<c020c67d>] check_unthrottle+0x3d/0x40
> [<c020c723>] n_tty_flush_buffer+0x13/0x60
> [<c0210107>] pty_flush_buffer+0x67/0x70
> [<c0208f55>] do_tty_hangup+0x405/0x470
> [<c020a4dc>] release_dev+0x64c/0x680
> [<c014abfb>] zap_pmd_range+0x4b/0x70
> [<c014ac63>] unmap_page_range+0x43/0x70
> [<c0170562>] dput+0x22/0x270
> [<c020a8aa>] tty_release+0x2a/0x60
> [<c015ac40>] __fput+0x100/0x120
> [<c0159229>] filp_close+0x59/0x90
> [<c0125b34>] put_files_struct+0x54/0xc0
> [<c0126795>] do_exit+0x155/0x3f0
> [<c0126aca>] do_group_exit+0x3a/0xb0
> [<c02fb427>] syscall_call+0x7/0xb
> 

Yes, this is due to a locking problem in do_tty_hangup() which everyone is
pretenting isn't there.


> PPP is build in, 
> 
> # CONFIG_PLIP is not set
> CONFIG_PPP=y
> # CONFIG_PPP_MULTILINK is not set
> CONFIG_PPP_FILTER=y
> CONFIG_PPP_ASYNC=y
> # CONFIG_PPP_SYNC_TTY is not set
> CONFIG_PPP_DEFLATE=y
> CONFIG_PPP_BSDCOMP=y
> CONFIG_PPPOE=y
> # CONFIG_SLIP is not set
> 
> 
> trying to start pppd doesn't work. Syslog:
> 
> Oct  4 00:05:39 JHome pppoe[2108]: ioctl(SIOCGIFHWADDR): Session 0: No
> such device
> Oct  4 00:05:39 JHome pppd[1134]: Serial connection established.
> Oct  4 00:05:39 JHome pppd[1134]: Couldn't get channel number:
> Input/output error

Odd.  -ENODEV against the ppp device I suppose.  test5-mm1 added the below
fix, which is only applicable if you're using devfs (are you using devfs?)
and is unlikely to explain this anyway.

Still, could you do a `patch -p1 -R' of the below, see what happens?


diff -puN drivers/net/ppp_generic.c~ppp-oops-fix drivers/net/ppp_generic.c
--- 25/drivers/net/ppp_generic.c~ppp-oops-fix	2003-09-09 23:41:40.000000000 -0700
+++ 25-akpm/drivers/net/ppp_generic.c	2003-09-09 23:41:40.000000000 -0700
@@ -792,7 +792,7 @@ static struct file_operations ppp_device
 
 /* Called at boot time if ppp is compiled into the kernel,
    or at module load time (from init_module) if compiled as a module. */
-int __init ppp_init(void)
+static int __init ppp_init(void)
 {
 	int err;
 
@@ -801,6 +801,8 @@ int __init ppp_init(void)
 	if (!err) {
 		err = devfs_mk_cdev(MKDEV(PPP_MAJOR, 0),
 				S_IFCHR|S_IRUSR|S_IWUSR, "ppp");
+		if (err)
+			unregister_chrdev(PPP_MAJOR, "ppp");
 	}
 
 	if (err)

_