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From: "vries at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>
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Subject: [Bug testsuite/26967] FAIL: gdb.base/longjmp.exp: next over longjmp(1)
Date: Wed, 27 Jan 2021 15:17:20 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D26967

--- Comment #2 from Tom de Vries <vries at gcc dot gnu.org> ---
While working on PR27205 I figured out what happens.

Without longjmp probes in libc, we try to fall back to using longjmp_names
breakpoints, but when these trigger we don't manage to recuperate the pc fr=
om
jmp_buf because tdep->jb_pc_offset is not set (in other words, -1).

Perhaps this once was set, but switched off due to problems.  There are kno=
wn
issues with this for linux related to pointer guarding of the pc in jmp_buf.

Anyway, we could detect this in the "set debug infrun 1" output:
...
  [infrun] process_event_stop_test: BPSTAT_WHAT_SET_LONGJMP_RESUME
(!gdbarch_get_longjmp_target)
...
and then allow the behaviour reported in this PR.

However, AFAIU that still wouldn't work for -m32, because there
tdep->jb_pc_offset is defined and then we run into pointer guarding (see
PR27205 for what that looks like).

--=20
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