* Herbert Xu [off-list ref] wrote:

On Mon, Dec 29, 2008 at 03:14:17PM +0100, Ingo Molnar wrote:

quoted

my testing efforts today are not particularly dominated by luck :-)

Below is the latest splat that i got with Peter's patch plus the revert of 
dd24c00191 applied.

quoted

[   78.679386] 
[   78.679389] =================================
[   78.680039] [ INFO: inconsistent lock state ]
[   78.680039] 2.6.28-tip-03885-g44c31d5-dirty #13188
[   78.680039] ---------------------------------
[   78.680039] inconsistent {softirq-on-W} -> {in-softirq-W} usage.
[   78.680039] ssh/4054 [HC0[0]:SC1[1]:HE1:SE0] takes:
[   78.680039]  (key#8){-+..}, at: [<c042710e>] __percpu_counter_add+0x52/0x7a
[   78.680039] {softirq-on-W} state was registered at:
[   78.680039]   [<c0163e6e>] __lock_acquire+0x288/0xa93
[   78.680039]   [<c01646d6>] lock_acquire+0x5d/0x7a
[   78.680039]   [<c0ae0473>] _spin_lock+0x20/0x2f
[   78.680039]   [<c042710e>] __percpu_counter_add+0x52/0x7a
[   78.680039]   [<c09c3e2f>] percpu_counter_add+0xf/0x12
[   78.680039]   [<c09c50ef>] tcp_v4_init_sock+0xe5/0xea

Right, this is the correct version of the earlier splat :)

Anyway, I've extended Peter's patch to cover the other cases.
Please let me know if it still bitches with this + Peter's fbc
patch.

net: Fix percpu counters deadlock

When we converted the protocol atomic counters such as the orphan
count and the total socket count deadlocks were introduced due to
the mismatch in BH status of the spots that used the percpu counter
operations.

Based on the diagnosis and patch by Peter Zijlstra, this patch
fixes these issues by disabling BH where we may be in process
context.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

thanks, will start testing it now.

One small nit: could you please add the Reported-by line for Jeff Kirscher 
who reported the problem originally:

 Reported-by: Jeff Kirsher [off-list ref]

	Ingo