On Mon, 2007-04-30 at 14:08 +0200, Stefan Wenk wrote:
> On Sunday 29 April 2007 23:20, Andrew Morton wrote:
> > (switch to email - please retain all ccs)
> >
> > On Sun, 29 Apr 2007 13:01:25 -0700 [EMAIL PROTECTED] wrote:
> > > http://bugzilla.kernel.org/show_bug.cgi?id=8405
> > >
> > > Here is the log vor /var/log/messages:
> > >
> > > Apr 29 16:53:34 linux kernel: PPP Deflate Compression module registered
> > > Apr 29 16:53:47 linux pppd[9090]: pppd 2.4.4 started by root, uid 0
> > > Apr 29 16:53:47 linux pppd[9090]: Using interface ppp0
> > > Apr 29 16:53:47 linux pppd[9090]: Connect: ppp0 <--> /dev/pts/9
> > > Apr 29 16:53:47 linux pppd[9090]: kernel does not support PPP filtering
> > > Apr 29 16:53:47 linux pppd[9090]: Deflate (15) compression enabled
> > > Apr 29 16:53:47 linux pppd[9090]: Cannot determine ethernet address for
> > > proxy ARP Apr 29 16:53:47 linux pppd[9090]: local IP address 192.168.3.2
> > > Apr 29 16:53:47 linux pppd[9090]: remote IP address 192.168.3.1
> > > Apr 29 16:54:03 linux kernel: z_decompress0: inflate returned -5 ()
> > > Apr 29 16:54:03 linux pppd[9090]: PPPIOCGFLAGS flags: c030c0
> > > Apr 29 16:54:03 linux pppd[9090]: Lost compression sync: disabling
> > > compression
> > >
> > > I had a look at the kernel patch of 2.6.18 - the lib/zlib/zlib_inflate
> > > was changed a lot and for me it looks to be the reason of the problem.
> >
> > If you're referring to 4f3865fb57a04db7cca068fed1c15badc064a302,
> > "zlib_inflate: Upgrade library code to a recent version" then that was
> > mainly a zlib_inflate change, not a zlib_deflate change.
> >
> > But yes, I'd say that this patch might well have been the cause.
> >
> > http://userweb.kernel.org/~akpm/zlib-backout.patch is a backout patch
> > against 2.6.21. If you apply that to 2.6.21 does it make ppp work again?
>
> thanks for this backout patch. I have applied it to 2.6.21 and now pppd is
> working with deflate again.
The key line of that log is
"Apr 29 16:54:03 linux kernel: z_decompress0: inflate returned -5 ()"
linux/zlib.h says:
#define Z_BUF_ERROR (-5)
so somehow we're triggering a buffer error...
Looking at zlib_inflate() in lib/zlib_inflate/inflate.c, it seems that
error only occurs if we had success (Z_OK) but no remaining input/output
space. I suspect you can just have ppp_deflate ignore that "error" code
and it might just work.
Can you try the following patch:
Index: linux-2.6.20/drivers/net/ppp_deflate.c
===================================================================
--- linux-2.6.20.orig/drivers/net/ppp_deflate.c 2007-02-04 18:44:54.000000000
+0000
+++ linux-2.6.20/drivers/net/ppp_deflate.c 2007-04-30 14:27:08.000000000
+0100
@@ -487,12 +487,16 @@ int z_decompress(void *arg, unsigned cha
*/
for (;;) {
r = zlib_inflate(&state->strm, Z_PACKET_FLUSH);
- if (r != Z_OK) {
+ if ((r != Z_OK) && (r != Z_BUF_ERROR)) {
if (state->debug)
printk(KERN_DEBUG "z_decompress%d: inflate
returned %d (%s)\n",
state->unit, r, (state->strm.msg?
state->strm.msg: ""));
return DECOMP_FATALERROR;
}
+ if (r == Z_BUF_ERROR) {
+ printk(KERN_DEBUG "z_decompress%d: Would have triggered
an error as inflate returned %d (%s)\n",
+ state->unit, r, (state->strm.msg?
state->strm.msg: ""));
+ }
if (state->strm.avail_out != 0)
break; /* all done */
if (decode_proto) {
This should continue but print some debug output when the problem
occurs.
Richard
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