Hi Pritha, You should attach gdb to the CPU before the panic occurs and set a breakpoint on the panic symbol.
Thanks, Ali Sent from my ARM powered mobile device On May 26, 2012, at 11:46 AM, Pritha Ghoshal <pritha9...@neo.tamu.edu> wrote: > Hi, > > I tried using the remote gdb mentioned in the debugging page, but I am > running a 4 core simulation, and even though one core gets a oops, the other > cores keep working. I attached the remote gdb to the failing core, but it > does not seem to stop simulation there and therefore I am not able to > backtrace. Do you know of any way I could make the simulation stop once 1 of > the cpu-s get a panic? > > Thanks > Pritha > > ----- Original Message ----- > From: "Pritha Ghoshal" <pritha9...@neo.tamu.edu> > To: sa...@umich.edu, "gem5 users mailing list" <gem5-users@gem5.org> > Sent: Tuesday, May 15, 2012 1:05:40 PM > Subject: Re: [gem5-users] Kernel panic in skb_release_data in put_page call > > Hi Ali, > > Thanks for your reply. It seems that the error is coming because the tx_ring > clearer thinks that the nr_frags is set on the skb and also sees a frag_list. > I cannot see these values getting set in the transmit path, when it pushes > into the tx_queue in the xmit_frame code. In the trace I am using I should > not have any fragmented packets. > > I am trying to hack it now to reset the nr_frags and the frag_list and see if > the problem goes, but I will dig into it more to see how these values are > getting set in the first place. > > By the way, I am not sure how to hook up gdb to the kernel running on gem5? > This is inside the kernel, so I was not sure how to run gdb on it. > > Thanks, > Pritha > > ----- Original Message ----- > From: "Ali Saidi" <sa...@umich.edu> > To: "gem5 users mailing list" <gem5-users@gem5.org> > Sent: Tuesday, May 15, 2012 12:34:41 AM > Subject: Re: [gem5-users] Kernel panic in skb_release_data in put_page call > > > > > You're going to have to get gdb hooked up to gem5 and see where that address > is coming from and why its bad. With alpha all the kernel addresses should > start with ffffc, so some how something is going wrong. You can also try > sprinking printks or dprintks through the code to see where the address is > being generated. Once you track how it's computed, you can see where it is > loaded from and then go looking for who wrote that last and why it was wrong. > > > > Ali > > > > On 15.05.2012 01:08, Pritha Ghoshal wrote: > > Hi, > > I am trying to use two e1000 drivers to simulate an incoming port and an > outgoing port. I have the iptables setup in between to regulate traffic and > let only some packets proceed to the outgoing port. I have modified the > networking part of the kernel as follows: > 1. I added a virtual device driver which sits on top of eth0 and eth1. > 2. This device calls the iptable functions by using the NF_HOOK mechanism for > all three hooks - PRE_ROUTING, FORWARD, POST_ROUTING. > 3. I have removed the NF_HOOK calls from places like ip_rcv, ip_forward and > ip_output, the functions that were being called through NF_HOOKS are being > called directly now. > > When I try to run packets through this setup, it works well till 1000 > packets. In the experiment where I try to send 10,000 packets, I get a kernel > panic: > Unable to handle kernel paging request at virtual address 0000074a7b000000^M > CPU 0 ksoftirqd/0(4): Oops 0^M > pc = [] ra = [] ps = 0000 Tainted: G W^M > pc is at put_page+0x28/0x190^M > ra is at skb_release_data+0xe8/0x120^M > v0 = 0000000000000000 t0 = fffffc001da7e350 t1 = 0000000000006000^M > t2 = 0000000000000001 t3 = 0000000000000068 t4 = 0008000400000000^M > t5 = 0000000000000000 t6 = 0000000000000002 t7 = fffffc001f04c000^M > s0 = 0000074a7b000000 s1 = fffffc001e40bbc0 s2 = 0000000000000069^M > s3 = fffffc001f248000 s4 = 0000000000000068 s5 = fffffc001f37e680^M > s6 = 0000000000000001^M > a0 = 0000074a7b000000 a1 = 000000009da7e2d2 a2 = 0000000000000068^M > a3 = 0000000000000001 a4 = fffffc001f2f6800 a5 = fffffc001da897c0^M > t8 = 0000000000000000 t9 = 0000000000000000 t10= 0000000002000000^M > t11= ffffffffffffffff pv = fffffc000037ddc0 at = 0000000000000020^M > gp = fffffc000086fc60 sp = fffffc001f04fc38^M > Trace:^M > [] skb_release_data+0xe8/0x120^M > [] __kfree_skb+0x1c/0x120^M > [] dev_kfree_skb_any+0x40/0x70^M > [] e1000_unmap_and_free_tx_resource+0x30/0x80^M > [] e1000_clean+0xec/0x720^M > [] net_rx_action+0x1d8/0x2c0^M > [] __do_softirq+0x13c/0x170^M > [] do_softirq+0x74/0x80^M > [] kthread+0x0/0xc0^M > [] ksoftirqd+0xb0/0x170^M > [] kthread+0x70/0xc0^M > [] ksoftirqd+0x0/0x170^M > [] kernel_thread+0x28/0x90^M > > It is giving an error in put_page call in the skb_release_data function. > Could someone help me in this? I am not sure how to proceed to debug this.. > > Thanks, > Pritha > > _______________________________________________ > gem5-users mailing list gem5-users@gem5.org > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users > > > > _______________________________________________ > gem5-users mailing list > gem5-users@gem5.org > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users > _______________________________________________ > gem5-users mailing list > gem5-users@gem5.org > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users > _______________________________________________ gem5-users mailing list gem5-users@gem5.org http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
