[lkml]   [2007]   [Mar]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Subjectutrace, RCU and ia64
Hi, Roland, Andrew.

Something really sick is going on with combination of utrace, RCU and ia64.

Below are quickly reproducable oops happenning on 8-way SMP,
my lame-o attempts to decode it, and test program itself.

I checked 2.6.21-rc5 which was OK,
2.6.21-rc5 + linux-2.6.21-current-utrace.patch which was bad, and
2.6.21-rc5-mm1 which was also bad.

Unable to handle kernel paging request at virtual address 6b6b6b6b6b6b6b6b
expl_ptratt[4391]: Oops 11012296146944 [1]
Modules linked in: autofs4 hidp rfcomm l2cap bluetooth sunrpc 8021q bridge ipv6 xt_length ipt_ttl xt_tcpmss iptable_mangle iptable_filter xt_multiport xt_limit ipt_tos ipt_REJECT ip_tables x_tables vfat fat button parport_pc lp parport sg e100 e1000 mii shpchp ide_cd cdrom dm_snapshot dm_zero dm_mirror dm_mod mptsas mptscsih mptbase scsi_transport_sas sd_mod scsi_mod ext3 jbd ehci_hcd ohci_hcd uhci_hcd
Pid: 4391, CPU 4, comm: expl_ptratt
psr : 0000121008026018 ifs : 8000000000000389 ip : [<a000000100094881>] Not tainted
ip is at __rcu_process_callbacks+0x3e1/0x660
unat: 0000000000000000 pfs : 0000000000000389 rsc : 0000000000000003
rnat: 0000000000000000 bsps: 0000000000000000 pr : 0000000000555965
ldrs: 0000000000000000 ccv : 0000000000000000 fpsr: 0009804c0270033f
csd : 0000000000000000 ssd : 0000000000000000
b0 : a0000001000948a0 b6 : a0000001000d9ee0 b7 : a000000100010080
f6 : 1003e6b6b6b6b6b6b6b6b f7 : 1003e0000000003333334
f8 : 1003e0000000000001680 f9 : 1003e0000000000001680
f10 : 1003e0000000000000048 f11 : 1003e0000000000000050
r1 : a000000100d130a0 r2 : 0000000000000003 r3 : 0000000000000001
r8 : e000000468054028 r9 : e000000468054000 r10 : 0000000000000004
r11 : a00000010095a880 r12 : e000000467bcfc30 r13 : e000000467bc8000
r14 : e0000004681452e8 r15 : e000000107f77940 r16 : e000000107f77978
r17 : 0000000000000002 r18 : 000000000000000a r19 : e000000467bc8c34
r20 : 0000000000000020 r21 : e000000108bb2cac r22 : e000000108a8cdc8
r23 : 0000000000000002 r24 : e0000001000065d8 r25 : 6b6b6b6b6b6b6b6b
r26 : e000000108bb2cc0 r27 : 0000000000000002 r28 : 0000000000000002
r29 : 0000000000004000 r30 : 0000000000004000 r31 : 0000000000000011
Call Trace:
[<a000000100012380>] show_stack+0x40/0xa0
sp=e000000467bcf7c0 bsp=e000000467bc9040
[<a000000100012c80>] show_regs+0x840/0x880
sp=e000000467bcf990 bsp=e000000467bc8fe0
[<a000000100034d80>] die+0x1c0/0x2a0
sp=e000000467bcf990 bsp=e000000467bc8f98
[<a0000001005db5b0>] ia64_do_page_fault+0x8d0/0xa00
sp=e000000467bcf9b0 bsp=e000000467bc8f48
[<a00000010000b300>] ia64_leave_kernel+0x0/0x280
sp=e000000467bcfa60 bsp=e000000467bc8f48
[<a000000100094880>] __rcu_process_callbacks+0x3e0/0x660
sp=e000000467bcfc30 bsp=e000000467bc8f00
[<a000000100094b40>] rcu_process_callbacks+0x40/0xa0
sp=e000000467bcfc30 bsp=e000000467bc8ee0
[<a000000100078fd0>] tasklet_action+0x1d0/0x340
sp=e000000467bcfc30 bsp=e000000467bc8eb8
[<a0000001000785b0>] __do_softirq+0xf0/0x240
sp=e000000467bcfc30 bsp=e000000467bc8e40
[<a000000100078770>] do_softirq+0x70/0xc0
sp=e000000467bcfc30 bsp=e000000467bc8dd8
[<a0000001000789c0>] irq_exit+0x80/0xa0
sp=e000000467bcfc30 bsp=e000000467bc8dc0
[<a000000100010030>] ia64_handle_irq+0x250/0x280
sp=e000000467bcfc30 bsp=e000000467bc8d90
[<a00000010000b300>] ia64_leave_kernel+0x0/0x280
sp=e000000467bcfc30 bsp=e000000467bc8d90
[<a0000001005d6940>] _spin_unlock_irqrestore+0x40/0x80
sp=e000000467bcfe00 bsp=e000000467bc8d60
[<a000000100064cf0>] wait_task_inactive+0x90/0x120
sp=e000000467bcfe00 bsp=e000000467bc8d38
[<a0000001000e1a70>] sys_ptrace+0x890/0x1180
sp=e000000467bcfe10 bsp=e000000467bc8cb0
[<a00000010000b0b0>] ia64_trace_syscall+0xd0/0x110
sp=e000000467bcfe30 bsp=e000000467bc8cb0
[<a000000000010620>] __start_ivt_text+0xffffffff00010620/0x400
sp=e000000467bd0000 bsp=e000000467bc8cb0
Kernel panic - not syncing: Aiee, killing interrupt handler!
a0000001000944a0 <__rcu_process_callbacks>:
a000000100094830: nop.m 0x0
a000000100094836: cmp.eq p8,p9=0,r39;; # while (list)
a00000010009483c: nop.i 0x0

a000000100094840: (p09) mov r35=1
a000000100094846: nop.m 0x0
a00000010009484c: (p09) br.cond.dptk.few a0000001000948e0 <__rcu_process_callbacks+0x440>

a000000100094850: nop.m 0x0
a000000100094856: nop.i 0x0
a00000010009485c: br.few a000000100094ae0 <__rcu_process_callbacks+0x640>

a000000100094860: nop.m 0x0
a000000100094866: ld8 r34=[r14],8 # r34 = next = list->next
# r14 = &list->func
a00000010009486c: nop.i 0x0;;

a000000100094870: lfetch [r34] # prefetch(next)
a000000100094876: nop.m 0x0
a00000010009487c: nop.i 0x0;;

a000000100094880: ld8 r25=[r14];; # r25 = list->func
a000000100094886: ===> ld8 r26=[r25],8 # something with something called .opd (?)
# I couldn't understand
a00000010009488c: nop.i 0x0;;

a000000100094890: ld8 r1=[r25]
a000000100094896: mov b6=r26
a00000010009489c: b0=b6;; # list->func()

Looks like place corresponds to function call in rcu_do_batch()

list = rdp->donelist;
while (list) {
next = list->next;
list = next;

#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/ptrace.h>
#include <signal.h>

static void *thread_func(void *arg)
execl("/proc/self/exe", NULL);
return NULL;

int main(int argc, const char *argv[])
pthread_t thread;
int pid, n;

if (argv[0] && (pid = fork()))
for (n = 1;; ++n) {
ptrace(PTRACE_ATTACH, pid, NULL, 0);
ptrace(PTRACE_DETACH, pid, NULL, 0);
if (!(n % 100000))
printf("passed: %d\n", n);

if (pthread_create(&thread, NULL, thread_func, NULL))

while (1)
return 1;

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2007-03-29 19:03    [W:0.042 / U:1.772 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site