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From: "kees at outflux dot net" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug sanitizer/94307] New: Provide a way to declare the *SAN
 exception handler -fsanitize-undefined-trap-on-error
Date: Tue, 24 Mar 2020 18:17:52 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D94307

            Bug ID: 94307
           Summary: Provide a way to declare the *SAN exception handler
                    -fsanitize-undefined-trap-on-error
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kees at outflux dot net
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxi=
n at gcc dot gnu.org
  Target Milestone: ---

Instead of unconditionally calling __builtin_trap() for
-fsanitize-undefined-trap-on-error it would help the Linux kernel's use of
UBSAN to have a way to specify the trap function. With that, Linux can use =
its
own internal exception handling routines and avoid various confused states:

https://lore.kernel.org/linux-next/20200324164433.qusyu5h7ykx3f2bu@treble/

For example something like -fsanitize-undefined-trap-function=3D__ubsan_tra=
p and
"__ubsan_trap" can then be defined by the kernel itself. Using the standard
handler routines (__ubsan_handle_*) are too heavy duty for some builds, so a
regular trap is needed for the kernel, but this allows us to provide a
"continue anyway" option as well.=