On Sun, 16 Dec 2007 15:10:14 -0500 "Miles Lane" [off-list ref] wrote:

On Dec 16, 2007 3:19 AM, Herbert Xu [off-list ref] wrote:

quoted

On Sat, Dec 15, 2007 at 11:56:04PM -0800, Andrew Morton wrote:

quoted

On Sun, 16 Dec 2007 01:37:01 -0500 "Miles Lane" [off-list ref] wrote:

quoted

quoted

On Sun, Dec 16, 2007 at 11:07:07AM +0800, Herbert Xu wrote:

So I posted this patch after 19:00 PST on 15 Dec.

quoted

quoted

Dec 15 13:44:39 syntropy kernel:  #0:  (&p->lock){--..}, at:
[crypto_algapi:seq_read+0x25/0x191c1] seq_read+0x25/0x26f

So your kernel is still feeding garbage into lockdep.

Are you really really sure that kernel had Herbert's patch applied?

The above log message is stamped as 13:44 PST.  I gotta say
this doesn't look good :)

Yes, I did have the patch applied, but I had reenabled LOCKDEP_DEBUG.
I just tried with the LOCKDEP_DEBUG stuff turned off, and with this
configuration, the problem is resolved.  It seems that the patch
you made does fix the problem with /proc/net/packet. This new issue
seems to be a different problem.

So, I tried building another kernel with LOCKDEP enabled (.config attached):
With this kernel, I got:

Dec 16 11:21:39 syntropy kernel: [  278.723108] process `tail' is
using deprecated sysctl (syscall) net.ipv6.neigh.default.retrans_time;
Use net.ipv6.neigh.default.retrans_time_ms instead.
Dec 16 11:21:40 syntropy kernel: [  279.226103] in_atomic():1, irqs_disabled():0
Dec 16 11:21:40 syntropy kernel: [  279.226106] no locks held by tail/6208.
Dec 16 11:21:40 syntropy kernel: [  279.226109] Pid: 6208, comm: tail
Not tainted 2.6.24-rc5-mm1 #5
Dec 16 11:21:40 syntropy kernel: [  279.226112]
[show_trace_log_lvl+0x12/0x25] show_trace_log_lvl+0x12/0x25
Dec 16 11:21:40 syntropy kernel: [  279.226121]  [show_trace+0xd/0x10]
show_trace+0xd/0x10
Dec 16 11:21:40 syntropy kernel: [  279.226126]
[sbp2:dump_stack+0x57/0x17c1] dump_stack+0x57/0x5f
Dec 16 11:21:40 syntropy kernel: [  279.226130]
[firewire_core:__might_sleep+0xd7/0x29a] __might_sleep+0xd7/0xde
Dec 16 11:21:40 syntropy kernel: [  279.226136]
[parport:copy_to_user+0x32/0xd13f] copy_to_user+0x32/0x47
Dec 16 11:21:40 syntropy kernel: [  279.226141]
[add_to_pagemap+0x29/0x56] add_to_pagemap+0x29/0x56
Dec 16 11:21:40 syntropy kernel: [  279.226147]
[pagemap_pte_range+0x74/0xb1] pagemap_pte_range+0x74/0xb1
Dec 16 11:21:40 syntropy kernel: [  279.226151]
[walk_page_range+0x115/0x1dc] walk_page_range+0x115/0x1dc
Dec 16 11:21:40 syntropy kernel: [  279.226157]
[pagemap_read+0x154/0x1e8] pagemap_read+0x154/0x1e8
Dec 16 11:21:40 syntropy kernel: [  279.226161]  [vfs_read+0xa2/0x11e]
vfs_read+0xa2/0x11e
Dec 16 11:21:40 syntropy kernel: [  279.226166]  [sys_read+0x3b/0x60]
sys_read+0x3b/0x60
Dec 16 11:21:40 syntropy kernel: [  279.226170]
[sysenter_past_esp+0x6b/0xc1] sysenter_past_esp+0x6b/0xc1

(Can you find a way to fix that wordwrapping please?)

Yes, this is a different bug - the pagemap stuff is doing userspace access
under kmap_atomic() - we discovered this a couple of days ago and Matt has
been informed.

It's relatively harmless and if that's the only problem you're observing
then I think we're OK here.