> intrepid:~$ cat test.pl
> #!/usr/bin/perl
>
> open my $fd, "-|", "/bin/true";
>
> intrepid:~$ strace -f ./test.pl
>
> Unable to handle kernel NULL pointer dereference at virtual address 00000000
> printing eip:
> 00000000
> *pde = 00000000
> Oops: 0000 [#1]
> PREEMPT
> Modules linked in: binfmt_misc ohci1394 ieee1394 pci200syn hdlc syncppp
> emu10k1_gp snd_cmipci gameport snd_opl3_lib snd_mpu401_uart epic100 sg
> sym53c8xx scsi_transport_spi evdev
> CPU: 0
> EIP: 0060:[<00000000>] Not tainted VLI
> EFLAGS: 00010286 (2.6.12-rc3)
> EIP is at 0x0
> eax: ca476000 ebx: 01200011 ecx: 00000000 edx: 00000000
> esi: cfbd3060 edi: 00000000 ebp: ca476000 esp: ca476fc4
> ds: 007b es: 007b ss: 0068
> Process test.pl (pid: 3168, threadinfo=ca476000 task=cfbd3060)
> Stack: 01202011 00000000 00000000 00000000 b7c9a708 bfea12cc 00000000 0000007b
> 0000007b 00000078 ffffe410 00000073 00000282 bfea121c 0000007b
> Call Trace:
> Code: Bad EIP value.
>
> 2.6.12-rc3 (current), gcc version 3.4.3 20050227 (Red Hat 3.4.3-22.fc3),
> Athlon XP.
>
> The machine is still alive, oops is 100% reproducible.
>
> 3174 ? Ss 0:00 \_ xterm -rv
> 3176 pts/1 Ss 0:00 \_ bash
> 3210 pts/1 S+ 0:00 \_ strace -f ./test.pl
> 3211 pts/1 T+ 0:00 \_ /usr/bin/perl ./test.pl
> 3212 pts/1 Z+ 0:00 \_ [test.pl] <defunct>
>
> Any idea?
Ok tested here, it's the ptrace scribbles the return address due to
incorrect esp0 at fork time (it's in -mm currently).
Could you please verify that this fixes it
Index: latest/arch/i386/kernel/process.c
===================================================================
--- latest.orig/arch/i386/kernel/process.c 2005-04-30 15:44:02.000000000 +0200
+++ latest/arch/i386/kernel/process.c 2005-05-03 12:54:16.000000000 +0200
@@ -400,11 +400,6 @@
int err;
childregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
- *childregs = *regs;
- childregs->eax = 0;
- childregs->esp = esp;
-
- p->thread.esp = (unsigned long) childregs;
/*
* The below -8 is to reserve 8 bytes on top of the ring0 stack.
* This is necessary to guarantee that the entire "struct pt_regs"
@@ -415,7 +410,13 @@
* "struct pt_regs" is possible, but they may contain the
* completely wrong values.
*/
- p->thread.esp0 = (unsigned long) (childregs+1) - 8;
+ childregs = (struct pt_regs *) ((unsigned long) childregs - 8);
+ *childregs = *regs;
+ childregs->eax = 0;
+ childregs->esp = esp;
+
+ p->thread.esp = (unsigned long) childregs;
+ p->thread.esp0 = (unsigned long) (childregs+1);
p->thread.eip = (unsigned long) ret_from_fork;
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]