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kvm-85rc5 Segmentation fault for m >= 2046 GB

DISCUSSION Donald Parsons 2 participants 4 messages Apr 12, 2009 – Apr 14, 2009 KVM

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Donald Parsons

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#0 lore raw

Required info:
Intel Core 2 Duo E6600
kvm version kvm-85rc5 seg faults (rc[13] fine; rc[24]?) Host kernel version: 2.6.29.1 SMP x86_64 (on Fedora 10)
Guest: Fedora 11 beta x86_64 (host and guest updated) qemu cmd line:
/usr/local/kvm/bin/qemu-system-x86_64 fc11Beta.img -m 2048 &
Problem still present with either of -no-kvm-irqchip or
-no-kvm-pit switch
Problem also appears with the -no-kvm switch

In trying to make the core file smaller I found the seg fault disappeared for anything less than 2048
and still appeared for other values above 2048. (Interesting thing, m=2046 and 2047 got a little further, window changed size before seg fault). Everything up to 2045 worked.
Seg fault occurs quite early, last thing seen is:
"Press F12 for boot menu"
followed by segfault about 3.5 to 4 seconds later.

Seems to be a problem with http://www.linux-kvm.org/page/Bugs
where it says about core files "Then get a backtrace of the error with" followed by nothing?

dmesg shows:

(these for m>=2048)
qemu-system-x86[9392] general protection ip:43c8e9 sp:7fffdfd955d0 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9394] general protection ip:43c8e9 sp:7fffee13e970 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9462] general protection ip:43c8e9 sp:7fff21ce3510 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9522] general protection ip:43c8e9 sp:7fff7b4d4d10 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9525] general protection ip:43c8e9 sp:7fff11aba2f0 error:0 in qemu-system-x86_64[400000+1f2000]

(next one m=2046)
qemu-system-x86[9540] general protection ip:43c8f4 sp:7fffd6020850 error:0 in qemu-system-x86_64[400000+1f2000]
(next one m=2047)
qemu-system-x86[9314] general protection ip:43c8f4 sp:7fffdcfe1810 error:0 in qemu-system-x86_64[400000+1f2000]

Don

#1 lore raw
Quoted 21 lines · Donald Parsons

Required info:
Intel Core 2 Duo E6600
kvm version kvm-85rc5 seg faults (rc[13] fine; rc[24]?) Host kernel version: 2.6.29.1 SMP x86_64 (on Fedora 10)
Guest: Fedora 11 beta x86_64 (host and guest updated) qemu cmd line:
/usr/local/kvm/bin/qemu-system-x86_64 fc11Beta.img -m 2048 &
Problem still present with either of -no-kvm-irqchip or
-no-kvm-pit switch
Problem also appears with the -no-kvm switch

In trying to make the core file smaller I found the seg fault disappeared for anything less than 2048
and still appeared for other values above 2048. (Interesting thing, m=2046 and 2047 got a little further, window changed size before seg fault). Everything up to 2045 worked.
Seg fault occurs quite early, last thing seen is:
"Press F12 for boot menu"
followed by segfault about 3.5 to 4 seconds later.

Quoted 3 lines

Seems to be a problem with http://www.linux-kvm.org/page/Bugs
where it says about core files "Then get a backtrace of the error with" followed by nothing?

# gdb -c core.xxx qemu/x86_64-softmmu/qemu-system-x86_64

(gdb) bt

Yes, the page is missing information, will be fixed.

Quoted 28 lines

dmesg shows:

(these for m>=2048)
qemu-system-x86[9392] general protection ip:43c8e9 sp:7fffdfd955d0 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9394] general protection ip:43c8e9 sp:7fffee13e970 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9462] general protection ip:43c8e9 sp:7fff21ce3510 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9522] general protection ip:43c8e9 sp:7fff7b4d4d10 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9525] general protection ip:43c8e9 sp:7fff11aba2f0 error:0 in qemu-system-x86_64[400000+1f2000]

(next one m=2046)
qemu-system-x86[9540] general protection ip:43c8f4 sp:7fffd6020850 error:0 in qemu-system-x86_64[400000+1f2000]
(next one m=2047)
qemu-system-x86[9314] general protection ip:43c8f4 sp:7fffdcfe1810 error:0 in qemu-system-x86_64[400000+1f2000]

Don

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author
#2 lore raw
Quoted 26 lines · Marcelo Tosatti
Quoted 21 lines · Donald Parsons

Required info:
Intel Core 2 Duo E6600
kvm version kvm-85rc5 seg faults (rc[13] fine; rc[24]?) Host kernel version: 2.6.29.1 SMP x86_64 (on Fedora 10)
Guest: Fedora 11 beta x86_64 (host and guest updated) qemu cmd line:
/usr/local/kvm/bin/qemu-system-x86_64 fc11Beta.img -m 2048 &
Problem still present with either of -no-kvm-irqchip or
-no-kvm-pit switch
Problem also appears with the -no-kvm switch

In trying to make the core file smaller I found the seg fault disappeared for anything less than 2048
and still appeared for other values above 2048. (Interesting thing, m=2046 and 2047 got a little further, window changed size before seg fault). Everything up to 2045 worked.
Seg fault occurs quite early, last thing seen is:
"Press F12 for boot menu"
followed by segfault about 3.5 to 4 seconds later.

Quoted 3 lines

Seems to be a problem with http://www.linux-kvm.org/page/Bugs
where it says about core files "Then get a backtrace of the error with" followed by nothing?

Quoted 27 lines
# gdb -c core.xxx qemu/x86_64-softmmu/qemu-system-x86_64

(gdb) bt

Yes, the page is missing information, will be fixed.

Quoted 21 lines

dmesg shows:

(these for m>=2048)
qemu-system-x86[9392] general protection ip:43c8e9 sp:7fffdfd955d0 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9394] general protection ip:43c8e9 sp:7fffee13e970 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9462] general protection ip:43c8e9 sp:7fff21ce3510 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9522] general protection ip:43c8e9 sp:7fff7b4d4d10 error:0 in qemu-system-x86_64[400000+1f2000] qemu-system-x86[9525] general protection ip:43c8e9 sp:7fff11aba2f0 error:0 in qemu-system-x86_64[400000+1f2000]

(next one m=2046)
qemu-system-x86[9540] general protection ip:43c8f4 sp:7fffd6020850 error:0 in qemu-system-x86_64[400000+1f2000]
(next one m=2047)
qemu-system-x86[9314] general protection ip:43c8f4 sp:7fffdcfe1810 error:0 in qemu-system-x86_64[400000+1f2000]

Okay, here is the backtrace:

Core was generated by `/usr/local/kvm/bin/qemu-system-x86_64 fc11Beta.img -m 2048 -no-quit'.
Program terminated with signal 11, Segmentation fault. #0 0x000000000043c8e9 in fprintf ()
(gdb) bt

#0  0x000000000043c8e9 in fprintf ()
#1  0x00000000004951fa in fprintf ()
#2  0x000000000040861e in fprintf ()
#3  0x00000000004096ca in fprintf ()
#4  0x000000000052302a in fprintf ()
#5  0x000000000040df05 in fprintf ()
#6  0x0000003fa421e576 in __libc_start_main () from /lib64/libc.so.6
#7  0x0000000000406c69 in fprintf ()
#8  0x00007fff8e91ee58 in ?? ()
#9  0x000000000000001c in ?? ()

#10 0x0000000000000005 in ?? ()
#11 0x00007fff8e91f81d in ?? ()
#12 0x00007fff8e91f843 in ?? ()
#13 0x00007fff8e91f850 in ?? ()
#14 0x00007fff8e91f853 in ?? ()
#15 0x00007fff8e91f858 in ?? ()
#16 0x0000000000000000 in ?? ()

and dmesg shows for this same segfault:
loaded kvm module (kvm-85rc5)
qemu-system-x86[4551] general protection ip:43c8e9 sp:7fff8e91e100 error:0 in qemu-system-x86_64[400000+1f2000]

Don