Date: Sun, 07 Jan 2007 13:19:59 -0500 From: Randall Stewart <rrs@cisco.com> To: Craig Rodrigues <rodrigc@crodrigues.org> Cc: freebsd-current@freebsd.org Subject: Re: Witness warning with SCTP Message-ID: <45A139CF.3090909@cisco.com> In-Reply-To: <20070107171034.GA13836@crodrigues.org> References: <20070107171034.GA13836@crodrigues.org>
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Craig: Ok, I know what this is.. When we allocate a PCB we hold several locks. This prevents a conflict of say a sender allocating a PCB at the very same instant (this was one of my race condition bugs that was fixed recently). Now, each PCB has a small hash table it uses. We call hashinit() for this .. hashinit() does a malloc with M_WAITOK thus the warning. So, I either need to make another hashinit() function with a passed flag for the wait (seems the best way) OR make a sctp specific hashinit.. which I don't like doing.. Maybe I can change the name of hashinit() to hashinit_x() and then make hashinit() be a macro that calls hasinit_x with M_WAITOK.. then I could use hashinit_x() directly? Don't know what the best course is to go here... It is rather strange that I have not seen this, since like I said one of my machines is running with witness enabled .. hmm.. Anyway.. advice from others how I should proceed would be welcome.. hashinit_x() or an sctp specific hash_init?? R Craig Rodrigues wrote: > Hi, > > I am running one of the SCTP tests in the ACE library, > and am getting the following witness warning. Any ideas what the cause > is? > > Thanks. > > malloc(M_WAITOK) of "1024", forcing M_NOWAIT with the following non-sleepable locks held: > exclusive sleep mutex sctp-create (inp_create) r = 0 (0xc2ddded0) locked @ /usr/src/sys/netinet/sctp_input.c:4006 > KDB: stack backtrace: > db_trace_self_wrapper(c09bf21a) at db_trace_self_wrapper+0x25 > kdb_backtrace(1,400,c146d5a0,6,cbd70148,...) at kdb_backtrace+0x29 > witness_warn(5,0,c09dac6c,c09701c9) at witness_warn+0x192 > uma_zalloc_arg(c146d5a0,0,2) at uma_zalloc_arg+0x41 > malloc(400,c0a50840,2,c28cf3e4,cbd701ac,...) at malloc+0xb2 > hashinit(100,c0a50840,c2dde80c,f1,c28cf3e4,...) at hashinit+0x3b > sctp_inpcb_alloc(c28cf3e4) at sctp_inpcb_alloc+0x143 > sctp_attach(c28cf3e4,0,0) at sctp_attach+0x34 > sonewconn(c28a9530,2,c2ddff48,0,c09cf2c5,839) at sonewconn+0x119 > sctp_handle_cookie_echo(c297e900,14,20,c297e948,cbd70390,cbd70bbc,cbd70bc0,cbd70c20,0,0,0,cbd70384) at sctp_handle_cookie_echo+0x77e > sctp_process_control(c297e900,14,cbd70c08,1ac,c297e948,c297e954,c2dddc10,c2ddfa50,cbd70c20,cbd70be8) at sctp_process_control+0xd89 > sctp_common_input_processing(cbd70c3c,14,20,1ac,c297e948,c297e954,c2dddc10,0,c2de1570,0) at sctp_common_input_processing+0x72 > sctp_input(c297e900,14,ae,100007f,0,...) at sctp_input+0x2fa > ip_input(c297e900) at ip_input+0x5c5 > netisr_processqueue(c0af3658) at netisr_processqueue+0x6e > swi_net(0) at swi_net+0xc2 > ithread_execute_handlers(c210b6c0,c2129900) at ithread_execute_handlers+0x11e > ithread_loop(c20ed960,cbd70d38) at ithread_loop+0x67 > fork_exit(c06bbd2c,c20ed960,cbd70d38) at fork_exit+0xac > fork_trampoline() at fork_trampoline+0x8 > -- Randall Stewart NSSTG - Cisco Systems Inc. 803-345-0369 <or> 803-317-4952 (cell)
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