Messages in this thread | | | Subject | Re: IPF Montvale machine panic when running a network-relevent testing | From | "Zhang, Yanmin" <> | Date | Wed, 18 Jun 2008 13:12:02 +0800 |
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On Tue, 2008-06-17 at 20:37 -0700, David Miller wrote: > From: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com> > Date: Wed, 18 Jun 2008 11:27:43 +0800 > > > This issue is caused by tcp defer accept. Mostly, process context calls lock_sock > > to apply a sleeping lock. BH (SoftIRQ) context calls bh_lock_sock(_nested) to just apply > > for the sk->sk_lock.slock without sleeping, then do appropriate processing based on > > if sk->sk_lock.owned==0. That works well if both process context and BH context operate > > the same sk at the same time. But with tcp defer accept, it doesn't, because > > process context(for example, in inet_csk_accept) locks the listen sk, while BH > > context (in tcp_v4_rcv, for example) locks the child sk and calls > > tcp_defer_accept_check => inet_csk_reqsk_queue_add => reqsk_queue_add, so there is a race > > to access the listen sock. > > > > Below patch against 2.6.26-rc6 fixes the issue. > > > > Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com> > > We reverted the guilty defer accept changes, please test Linus's > current tree. I happened to download git tree on June 16th, which includes the reverting patch.
I confirm it fixes the hang issue.
-yanmin
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