Debian Bug report logs - #1031946
gdb: one remaining breakage in rustc gdb testcases

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Fabian Grünbichler <debian@fabian.gruenbichler.email>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: gdb: one remaining breakage in rustc gdb testcases

Date: Sat, 25 Feb 2023 19:38:48 +0100

Package: gdb
Version: 13.1-1
Severity: normal
Control: affects -1 src:rustc

After the fix for #1031745 (thanks for the fast turnaround!), there
still is one test case (unsized.rs) that fails with gdb 13.1 (both -1
and -2), but didn't with 12.1.

I updated the reproducer repo[0], broken and good output look like this:

----8<---- broken
Breakpoint 1 at 0x81dd: file src/main.rs, line 88.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, rustc_gdb_1031745::main () at src/main.rs:88
88	    zzz(); // #break
$1 = &rustc_gdb_1031745::Foo<[u8]> 0x7fffffffdd88
$2 = &rustc_gdb_1031745::Foo<rustc_gdb_1031745::Foo<[u8]>> 0x7fffffffdd88
$3 = &rustc_gdb_1031745::Foo<dyn core::fmt::Debug> {pointer: 0x555555593034, vtable: 0x5555555a3000warning: (Internal error: pc 0x5555555a3000 in read in CU, but not in symtab.)
warning: (Error: pc 0x5555555a3000 in address map, but not in symtab.)
}
$4 = alloc::boxed::Box<rustc_gdb_1031745::Foo<dyn core::fmt::Debug>, alloc::alloc::Global> {pointer: 0x5555555a7ba0, vtable: 0x5555555a3000warning: (Internal error: pc 0x5555555a3000 in read in CU, but not in symtab.)
warning: (Error: pc 0x5555555a3000 in address map, but not in symtab.)
}
$5 = &(i32, i32, [i32]) [(0, 1, 0), (2, 3, 0)]
$6 = &(i32, i32, dyn core::fmt::Debug) {pointer: 0x5555555a3020, vtable: 0x5555555a3030warning: (Internal error: pc 0x5555555a3030 in read in CU, but not in symtab.)
warning: (Error: pc 0x5555555a3030 in address map, but not in symtab.)
}
---->8----

----8<---- good (gdb 12.1-4 from bookworm)
Breakpoint 1 at 0x81dd: file src/main.rs, line 88.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, rustc_gdb_1031745::main () at src/main.rs:88
88	    zzz(); // #break
$1 = &rustc_gdb_1031745::Foo<[u8]> {data_ptr: 0x7fffffffdd88, length: 4}
$2 = &rustc_gdb_1031745::Foo<rustc_gdb_1031745::Foo<[u8]>> {data_ptr: 0x7fffffffdd88, length: 4}
$3 = &rustc_gdb_1031745::Foo<dyn core::fmt::Debug> {pointer: 0x555555593034, vtable: 0x5555555a3000}
$4 = alloc::boxed::Box<rustc_gdb_1031745::Foo<dyn core::fmt::Debug>, alloc::alloc::Global> {pointer: 0x5555555a7ba0, vtable: 0x5555555a3000}
$5 = &(i32, i32, [i32]) {data_ptr: 0x555555593038, length: 2}
$6 = &(i32, i32, dyn core::fmt::Debug) {pointer: 0x5555555a3020, vtable: 0x5555555a3030}
---->8----

Since this no longer (fatally) affects the build of rustc, I opted for a
lower severity this time around. It looks like an issue with symbol
mapping/lookup again. Feel free to adjust if you consider this blocking.

0: https://salsa.debian.org/fg/rustc-gdb-1031745

-- System Information:
Debian Release: bookworm/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 6.1.0-5-amd64 (SMP w/16 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages gdb depends on:
ii  libbabeltrace1          1.5.11-1+b2
ii  libc6                   2.36-8
ii  libdebuginfod1          0.188-2.1
ii  libexpat1               2.5.0-1
ii  libgcc-s1               12.2.0-14
ii  libgmp10                2:6.2.1+dfsg1-1.1
ii  libipt2                 2.0.5-1
ii  liblzma5                5.4.1-0.2
ii  libmpfr6                4.2.0-1
ii  libncursesw6            6.4-2
ii  libpython3.11           3.11.2-4
ii  libreadline8            8.2-1.3
ii  libsource-highlight4v5  3.1.9-4.2+b2
ii  libstdc++6              12.2.0-14
ii  libtinfo6               6.4-2
ii  libxxhash0              0.8.1-1
ii  libzstd1                1.5.4+dfsg2-3
ii  zlib1g                  1:1.2.13.dfsg-1

Versions of packages gdb recommends:
ii  libc6-dbg [libc-dbg]  2.36-8

Versions of packages gdb suggests:
pn  gdb-doc    <none>
pn  gdbserver  <none>

-- no debconf information

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