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Diffstat (limited to 'gitlab/issues/target_i386/host_missing/accel_TCG/1143.toml')
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1 files changed, 0 insertions, 90 deletions
diff --git a/gitlab/issues/target_i386/host_missing/accel_TCG/1143.toml b/gitlab/issues/target_i386/host_missing/accel_TCG/1143.toml deleted file mode 100644 index 6d3bf3a17..000000000 --- a/gitlab/issues/target_i386/host_missing/accel_TCG/1143.toml +++ /dev/null @@ -1,90 +0,0 @@ -id = 1143 -title = "Breakpoints missed when a function is split into two memory pages." -state = "closed" -created_at = "2022-08-04T12:12:30.418Z" -closed_at = "2022-08-22T09:17:09.374Z" -labels = ["accel: TCG", "kind::Bug", "target: i386"] -url = "https://gitlab.com/qemu-project/qemu/-/issues/1143" -host-os = "Ubuntu 20.04" -host-arch = "x86_64" -qemu-version = "QEMU emulator version 7.0.50 (v7.0.0-1139-g78ac2eebba)" -guest-os = "n/a" -guest-arch = "n/a" -description = """Qemu seems to ignore some breakpoints when the start of a function is -in another page than where the breakpoint is set. - -In my case, I've a function `__gnat_debug_raise_exception` which starts at `0x10bff2` and I've set with gdb a breakpoint at `0x10c00e` (in another page). -While running with `qemu -d in_asm,exec`, I can see that the whole function is executed at once and that no breakpoint is fired. - -``` -(gdb) b *0x00108fbc -(gdb) b *0x0010c00e -(gdb) target remote :1234 -(gdb) c - -Trace 0: 0x7f277c0174c0 [0000000000000000/0000000000108fb9/0040c0b0/ff000201] ada__exceptions__complete_occurrence ----------------- - -// gdb hits first breakpoint here. -Breakpoint 3, 0x0000000000108fbc .... -(gdb) ni - -IN: ada__exceptions__complete_occurrence -0x00108fbc: e8 31 30 00 00 callq 0x10bff2 - -Trace 0: 0x7f277c000100 [0000000000000000/0000000000108fbc/0040c0b0/ff000e01] ada__exceptions__complete_occurrence ----------------- -IN: __gnat_debug_raise_exception -0x0010bff2: 55 pushq %rbp -0x0010bff3: 48 89 e5 movq %rsp, %rbp -0x0010bff6: 48 89 7d f8 movq %rdi, -8(%rbp) -0x0010bffa: 48 89 d1 movq %rdx, %rcx -0x0010bffd: 48 89 f0 movq %rsi, %rax -0x0010c000: 48 89 fa movq %rdi, %rdx -0x0010c003: 48 89 ca movq %rcx, %rdx -0x0010c006: 48 89 45 e0 movq %rax, -0x20(%rbp) -0x0010c00a: 48 89 55 e8 movq %rdx, -0x18(%rbp) -0x0010c00e: 48 8b 45 e0 movq -0x20(%rbp), %rax -0x0010c012: 90 nop -0x0010c013: 5d popq %rbp -0x0010c014: c3 retq - -Trace 0: 0x7f277c000100 [0000000000000000/000000000010bff2/0040c0b0/ff000000] __gnat_debug_raise_exception -Digging a bit more, it seems that it seems related to - -// gdb ni stop here. Breakpoints at 0x10c00e have been ignored. -``` - -Note that if I'm setting another breakpoint at `0x0010bffd` (thus not at the start of the function but still in the same page), the execution -will be executed step by step and the breakpoint at 0x10c00e will be triggered normally. - - -``` -IN: ada__exceptions__complete_occurrence -0x00108fbc: e8 31 30 00 00 callq 0x10bff2 - -Trace 0: 0x7f6af4000100 [0000000000000000/0000000000108fbc/0040c0b0/ff000e01] ada__exceptions__complete_occurrence ----------------- -IN: __gnat_debug_raise_exception -0x0010bff2: 55 pushq %rbp - -Trace 0: 0x7f6af4000100 [0000000000000000/000000000010bff2/0040c0b0/ff000201] __gnat_debug_raise_exception ----------------- -IN: __gnat_debug_raise_exception -0x0010bff3: 48 89 e5 movq %rsp, %rbp - -Trace 0: 0x7f6af4000280 [0000000000000000/000000000010bff3/0040c0b0/ff000201] __gnat_debug_raise_exception ----------------- -IN: __gnat_debug_raise_exception -0x0010bff6: 48 89 7d f8 movq %rdi, -8(%rbp) -... -``` - -I've dug a bit into qemu translator code and I guess `check_for_breakpoint` should check that the whole function is in the same page before skipping step by step. But I'm not sure if it's possible because the TB is created after `check_for_breakpoint` IIUC. - -Sadly as of now, I don't have a C reproducer. I can try to provide you my "foo" program which is an Ada program. But maybe if you've a better idea how to reproduce that or an idea of to fix that, I'll be glad to help you. - -Thanks, -Clément""" -reproduce = "n/a" -additional = "n/a" |