Hi,
I ran into this while playing with jprobes in 2.6.10.
I tried to install jprobe handler on a invalid address,
I get OOPS. I was hoping for a error check and a graceful
exit rather than kernel Oops.
Thanks,
Badari
plant jprobe at 00000000c01836b0, handler addr ffffffffa0000080
Unable to handle kernel paging request at 00000000c01836b0 RIP:
<ffffffff8026e622>{__memcpy+114}
PML4 17d6cf067 PGD 0
Oops: 0000 [1] SMP
CPU 1
Modules linked in: diotest
Pid: 14225, comm: insmod Not tainted 2.6.10n
RIP: 0010:[<ffffffff8026e622>] <ffffffff8026e622>{__memcpy+114}
RSP: 0018:000001019b841d58 EFLAGS: 00010047
RAX: ffffff0000a70000 RBX: 00000101bfa44200 RCX: 0000000000000000
RDX: 000000000000000f RSI: 00000000c01836b0 RDI: ffffff0000a70000
RBP: ffffffffa00008e0 R08: 0000010180000000 R09: 0000000000000000
R10: 00000101bfa44218 R11: 0000000000000111 R12: 0000000000000216
R13: ffffffff804f1440 R14: 0000000000000020 R15: 0000000000000002
FS: 0000002a9588e6e0(0000) GS:ffffffff80628800(0000)
knlGS:0000000055970080
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000000c01836b0 CR3: 00000001a072c000 CR4: 00000000000006e0
Process insmod (pid: 14225, threadinfo 000001019b840000, task
00000101bf9394e0)
Stack: 00000101bfa44200 ffffffff8011edcc 0000000000000212
ffffffffa00008e0
00000000ffffffef ffffffff80158542 ffffffff804f1480
ffffffffa0000940
ffffffff804f1440 ffffffffa000005c
Call Trace:<ffffffff8011edcc>{arch_prepare_kprobe+300}
<ffffffff80158542>{register_kprobe+82}
<ffffffffa000005c>{:diotest:init_dmods+44}
<ffffffff80150823>{sys_init_module+6387}
<ffffffff8015e9c0>{__pagevec_free+32}
<ffffffff8016490e>{release_pages+382}
<ffffffff8016d4e6>{do_munmap+918}
<ffffffff803ebb11>{__down_read+49}
<ffffffff8026bc90>{__up_write+48}
<ffffffff8010e4ce>{system_call+126}
Code: 4c 8b 06 4c 89 07 48 8d 7f 08 48 8d 76 08 75 ee 89 d1 83 e1
RIP <ffffffff8026e622>{__memcpy+114} RSP <000001019b841d58>
CR2: 00000000c01836b0
Hi Badri,
> Hi,
>
> I ran into this while playing with jprobes in 2.6.10.
>
> I tried to install jprobe handler on a invalid address,
User should prevent inserting jprobes on an invalid address.
> I get OOPS. I was hoping for a error check and a graceful
> exit rather than kernel Oops.
>
Error check and graceful exit can be done in the jprobe handler
module. In the jprobe network packet logging patch, error check
was taken care by using kallsyms_lookup_name() as shown below.
nt->jp.kp.addr = (kprobe_opcode_t *)
kallsyms_lookup_name(nt->funcname);
if (nt->jp.kp.addr) {
printk("plant jprobe at %s (%p), handler addr %p\n",
nt->funcname, nt->jp.kp.addr, nt->jp.entry);
register_jprobe(&nt->jp);
} else {
printk("couldn't find %s to plant jprobe\n",
nt->funcname);
}.
Please see the patch at the URL for more details.
http://lkml.org/lkml/2004/8/16/179
Thanks
Prasanna
> Unable to handle kernel paging request at 00000000c01836b0 RIP:
> <ffffffff8026e622>{__memcpy+114}
> PML4 17d6cf067 PGD 0
> Oops: 0000 [1] SMP
> CPU 1
> Modules linked in: diotest
> Pid: 14225, comm: insmod Not tainted 2.6.10n
> RIP: 0010:[<ffffffff8026e622>] <ffffffff8026e622>{__memcpy+114}
> RSP: 0018:000001019b841d58 EFLAGS: 00010047
> RAX: ffffff0000a70000 RBX: 00000101bfa44200 RCX: 0000000000000000
> RDX: 000000000000000f RSI: 00000000c01836b0 RDI: ffffff0000a70000
> RBP: ffffffffa00008e0 R08: 0000010180000000 R09: 0000000000000000
> R10: 00000101bfa44218 R11: 0000000000000111 R12: 0000000000000216
> R13: ffffffff804f1440 R14: 0000000000000020 R15: 0000000000000002
> FS: 0000002a9588e6e0(0000) GS:ffffffff80628800(0000)
> knlGS:0000000055970080
> CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> CR2: 00000000c01836b0 CR3: 00000001a072c000 CR4: 00000000000006e0
> Process insmod (pid: 14225, threadinfo 000001019b840000, task
> 00000101bf9394e0)
> Stack: 00000101bfa44200 ffffffff8011edcc 0000000000000212
> ffffffffa00008e0
> 00000000ffffffef ffffffff80158542 ffffffff804f1480
> ffffffffa0000940
> ffffffff804f1440 ffffffffa000005c
> Call Trace:<ffffffff8011edcc>{arch_prepare_kprobe+300}
> <ffffffff80158542>{register_kprobe+82}
> <ffffffffa000005c>{:diotest:init_dmods+44}
> <ffffffff80150823>{sys_init_module+6387}
> <ffffffff8015e9c0>{__pagevec_free+32}
> <ffffffff8016490e>{release_pages+382}
> <ffffffff8016d4e6>{do_munmap+918}
> <ffffffff803ebb11>{__down_read+49}
> <ffffffff8026bc90>{__up_write+48}
> <ffffffff8010e4ce>{system_call+126}
>
>
> Code: 4c 8b 06 4c 89 07 48 8d 7f 08 48 8d 76 08 75 ee 89 d1 83 e1
> RIP <ffffffff8026e622>{__memcpy+114} RSP <000001019b841d58>
> CR2: 00000000c01836b0
>
>
>
--
Prasanna S Panchamukhi
Linux Technology Center
India Software Labs, IBM Bangalore
Ph: 91-80-25044636
<[email protected]>
On Tue, 2005-02-08 at 21:07, Prasanna S Panchamukhi wrote:
> Hi Badri,
>
> > Hi,
> >
> > I ran into this while playing with jprobes in 2.6.10.
> >
> > I tried to install jprobe handler on a invalid address,
>
> User should prevent inserting jprobes on an invalid address.
Well, I was hoping register handler would do some basic
error checking to prevent user from panicking. For example,
I ran into it untentionally (I moved my code from ia32 to
x86-64, forgot to update the addresses).
>
> > I get OOPS. I was hoping for a error check and a graceful
> > exit rather than kernel Oops.
> >
>
> Error check and graceful exit can be done in the jprobe handler
> module. In the jprobe network packet logging patch, error check
> was taken care by using kallsyms_lookup_name() as shown below.
>
> nt->jp.kp.addr = (kprobe_opcode_t *)
> kallsyms_lookup_name(nt->funcname);
> if (nt->jp.kp.addr) {
> printk("plant jprobe at %s (%p), handler addr %p\n",
> nt->funcname, nt->jp.kp.addr, nt->jp.entry);
> register_jprobe(&nt->jp);
> } else {
> printk("couldn't find %s to plant jprobe\n",
> nt->funcname);
> }.
>
I tried to do this earlier in my module, but I get
# insmod myprobe.ko
insmod: error inserting 'myprobe.ko': -1 Unknown symbol in module
myprobe: Unknown symbol kallsyms_lookup_name
How did you use it ? it looks like kallsyms_lookup_name()
is not exported. Thats the reason why I was hardcoding addresses.
# grep KALL .config
CONFIG_KALLSYMS=y
CONFIG_KALLSYMS_ALL=y
CONFIG_KALLSYMS_EXTRA_PASS=y
Thanks,
Badari
On Wed, Feb 09, 2005 at 04:03:36PM -0800, Badari Pulavarty wrote:
> On Tue, 2005-02-08 at 21:07, Prasanna S Panchamukhi wrote:
[..]
> > >
> >
> > Error check and graceful exit can be done in the jprobe handler
> > module. In the jprobe network packet logging patch, error check
> > was taken care by using kallsyms_lookup_name() as shown below.
> >
> > nt->jp.kp.addr = (kprobe_opcode_t *)
> > kallsyms_lookup_name(nt->funcname);
> > if (nt->jp.kp.addr) {
> > printk("plant jprobe at %s (%p), handler addr %p\n",
> > nt->funcname, nt->jp.kp.addr, nt->jp.entry);
> > register_jprobe(&nt->jp);
> > } else {
> > printk("couldn't find %s to plant jprobe\n",
> > nt->funcname);
> > }.
> >
>
> I tried to do this earlier in my module, but I get
>
> # insmod myprobe.ko
> insmod: error inserting 'myprobe.ko': -1 Unknown symbol in module
> myprobe: Unknown symbol kallsyms_lookup_name
>
> How did you use it ? it looks like kallsyms_lookup_name()
> is not exported. Thats the reason why I was hardcoding addresses.
>
I checked the network packet logging patch, it also adds the
EXPORT_SYMBOL(kallsyms_lookup_name). :)
http://prdownloads.sourceforge.net/dprobes/plog.tar.gz?download
Maneesh
--
Maneesh Soni
Linux Technology Center,
IBM India Software Labs,
Bangalore, India
email: [email protected]
Phone: 91-80-25044990