Userspace debugging with QEMU/gdb
Hi,
From the page https://docs.sel4.systems/DebuggingGuide.html (section Userspace debugging), I know we can debug userspace process by command below:
---------------------------- cmd example start ---------------------------------------- gdb ./dynamic-2 Reading symbols from ./dynamic-2...done. (gdb) target remote :1234 Remote debugging using :1234 0x000000000000fff0 in ?? () (gdb) break main Breakpoint 1 at 0x402011: file sel4-tutorials-manifest/dynamic-2/main.c, line 161. (gdb) c Continuing. Breakpoint 1, main () at sel4-tutorials-manifest/dynamic-2/main.c:161 161 (gdb) ---------------------------- cmd example end ---------------------------------------- It works for normal userspace process (such as the example code in tutorials: https://docs.sel4.systems/Tutorials/dynamic-2.html ). But when I want to debug the userspace process for the code in the tutorials page https://docs.sel4.systems/Tutorials/camkes-vm-linux.html (one virtual machine in seL4), I cannot catch the breakpoints. So can you help me to explain why I cannot catch the breakpoint? and can we debug the vmm create process with qemu/gdb? Thanks.
Does it work if you try using hardware breakpoints? The camkes-vm-linux tutorial uses hardware virtualisation via kvm so the software breakpoints likely won't work. Replacing break with hbreak may fix your issue. ________________________________ From: Devel <devel-bounces@sel4.systems> on behalf of Jiusheng Liu <liujiusheng@gmail.com> Sent: Wednesday, 27 November 2019 1:51 PM To: devel@sel4.systems <devel@sel4.systems> Subject: [seL4] Userspace debugging with QEMU/gdb Hi,
From the page https://docs.sel4.systems/DebuggingGuide.html (section Userspace debugging), I know we can debug userspace process by command below:
---------------------------- cmd example start ---------------------------------------- gdb ./dynamic-2 Reading symbols from ./dynamic-2...done. (gdb) target remote :1234 Remote debugging using :1234 0x000000000000fff0 in ?? () (gdb) break main Breakpoint 1 at 0x402011: file sel4-tutorials-manifest/dynamic-2/main.c, line 161. (gdb) c Continuing. Breakpoint 1, main () at sel4-tutorials-manifest/dynamic-2/main.c:161 161 (gdb) ---------------------------- cmd example end ---------------------------------------- It works for normal userspace process (such as the example code in tutorials: https://docs.sel4.systems/Tutorials/dynamic-2.html ). But when I want to debug the userspace process for the code in the tutorials page https://docs.sel4.systems/Tutorials/camkes-vm-linux.html (one virtual machine in seL4), I cannot catch the breakpoints. So can you help me to explain why I cannot catch the breakpoint? and can we debug the vmm create process with qemu/gdb? Thanks.
hbreak works! I can catch the breakpoint when I use hbreak cmd. Thanks alot for your help! On Mon, Dec 2, 2019 at 1:45 PM Mcleod, Kent (Data61, Kensington NSW) < Kent.Mcleod@data61.csiro.au> wrote:
Does it work if you try using hardware breakpoints? The camkes-vm-linux tutorial uses hardware virtualisation via kvm so the software breakpoints likely won't work. Replacing break with hbreak may fix your issue. ------------------------------ *From:* Devel <devel-bounces@sel4.systems> on behalf of Jiusheng Liu < liujiusheng@gmail.com> *Sent:* Wednesday, 27 November 2019 1:51 PM *To:* devel@sel4.systems <devel@sel4.systems> *Subject:* [seL4] Userspace debugging with QEMU/gdb
Hi,
From the page https://docs.sel4.systems/DebuggingGuide.html (section Userspace debugging), I know we can debug userspace process by command below:
---------------------------- cmd example start ---------------------------------------- gdb ./dynamic-2 Reading symbols from ./dynamic-2...done. (gdb) target remote :1234 Remote debugging using :1234 0x000000000000fff0 in ?? () (gdb) break main Breakpoint 1 at 0x402011: file sel4-tutorials-manifest/dynamic-2/main.c, line 161. (gdb) c Continuing.
Breakpoint 1, main () at sel4-tutorials-manifest/dynamic-2/main.c:161 161 (gdb) ---------------------------- cmd example end ----------------------------------------
It works for normal userspace process (such as the example code in tutorials: https://docs.sel4.systems/Tutorials/dynamic-2.html ).
But when I want to debug the userspace process for the code in the tutorials page https://docs.sel4.systems/Tutorials/camkes-vm-linux.html (one virtual machine in seL4), I cannot catch the breakpoints.
So can you help me to explain why I cannot catch the breakpoint? and can we debug the vmm create process with qemu/gdb?
Thanks.
participants (2)
-
Jiusheng Liu -
Mcleod, Kent (Data61, Kensington NSW)