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* [Bug c/107963] New: Support __attribute__((disable_sanitizer_instrumentation))
@ 2022-12-04 6:38 i at maskray dot me
2022-12-04 6:45 ` [Bug sanitizer/107963] " pinskia at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: i at maskray dot me @ 2022-12-04 6:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107963
Bug ID: 107963
Summary: Support
__attribute__((disable_sanitizer_instrumentation))
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: i at maskray dot me
Target Milestone: ---
Clang introduced the attribute in https://reviews.llvm.org/D108029 (2021-08).
It disables instrumentations for all kinds of sanitizers.
For non-memory sanitizers, it's like the union of all available
no_sanitize("xxx").
For msan, it disables all instrumentations, therefore the following function
does not unpoison the shadow for *a, which may lead to a false positive for a
subsequent function
(https://clang.llvm.org/docs/MemorySanitizer.html#attribute-disable-sanitizer-instrumentation).
That said, such functionality is useful in some scenarios, e.g. `noinstr` in
the Linux kernel
(https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9b448bc25b776daab3215393c3ce6953dd3bb8ad)
__attribute__((disable_sanitizer_instrumentation)) int foo(int *a) {
*a = 42;
return *a;
}
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug sanitizer/107963] Support __attribute__((disable_sanitizer_instrumentation))
2022-12-04 6:38 [Bug c/107963] New: Support __attribute__((disable_sanitizer_instrumentation)) i at maskray dot me
@ 2022-12-04 6:45 ` pinskia at gcc dot gnu.org
2022-12-04 21:50 ` sam at gentoo dot org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-12-04 6:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107963
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
https://gcc.gnu.org/pipermail/gcc/2021-November/237787.html
If I read this correctly, there is no reason for a new attribute for gcc.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug sanitizer/107963] Support __attribute__((disable_sanitizer_instrumentation))
2022-12-04 6:38 [Bug c/107963] New: Support __attribute__((disable_sanitizer_instrumentation)) i at maskray dot me
2022-12-04 6:45 ` [Bug sanitizer/107963] " pinskia at gcc dot gnu.org
@ 2022-12-04 21:50 ` sam at gentoo dot org
2022-12-04 23:24 ` i at maskray dot me
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: sam at gentoo dot org @ 2022-12-04 21:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107963
Sam James <sam at gentoo dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |sam at gentoo dot org
--- Comment #2 from Sam James <sam at gentoo dot org> ---
(In reply to Andrew Pinski from comment #1)
> https://gcc.gnu.org/pipermail/gcc/2021-November/237787.html
>
> If I read this correctly, there is no reason for a new attribute for gcc.
Sounds like a possible documentation issue then.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug sanitizer/107963] Support __attribute__((disable_sanitizer_instrumentation))
2022-12-04 6:38 [Bug c/107963] New: Support __attribute__((disable_sanitizer_instrumentation)) i at maskray dot me
2022-12-04 6:45 ` [Bug sanitizer/107963] " pinskia at gcc dot gnu.org
2022-12-04 21:50 ` sam at gentoo dot org
@ 2022-12-04 23:24 ` i at maskray dot me
2022-12-05 0:01 ` pinskia at gcc dot gnu.org
2022-12-05 8:18 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: i at maskray dot me @ 2022-12-04 23:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107963
--- Comment #3 from Fangrui Song <i at maskray dot me> ---
GCC doesn't implement -fsanitize=memory.
In the absence of it, __attribute__((disable_sanitizer_instrumentation)) is
like __attribute__((no_sanitize("all"))).
When -fsanitize=memory is implemented, the two attribute will be different.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug sanitizer/107963] Support __attribute__((disable_sanitizer_instrumentation))
2022-12-04 6:38 [Bug c/107963] New: Support __attribute__((disable_sanitizer_instrumentation)) i at maskray dot me
` (2 preceding siblings ...)
2022-12-04 23:24 ` i at maskray dot me
@ 2022-12-05 0:01 ` pinskia at gcc dot gnu.org
2022-12-05 8:18 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-12-05 0:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107963
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Fangrui Song from comment #3)
> GCC doesn't implement -fsanitize=memory.
> In the absence of it, __attribute__((disable_sanitizer_instrumentation)) is
> like __attribute__((no_sanitize("all"))).
>
> When -fsanitize=memory is implemented, the two attribute will be different.
Why do you think GCC will implement no_sanitize that way. It already didn't
implement no_sanitize that way for -fsanitize=thread too.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug sanitizer/107963] Support __attribute__((disable_sanitizer_instrumentation))
2022-12-04 6:38 [Bug c/107963] New: Support __attribute__((disable_sanitizer_instrumentation)) i at maskray dot me
` (3 preceding siblings ...)
2022-12-05 0:01 ` pinskia at gcc dot gnu.org
@ 2022-12-05 8:18 ` rguenth at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-12-05 8:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107963
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |WONTFIX
Status|UNCONFIRMED |RESOLVED
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Yep, that would just be confusing. If "not unpoison the shadow for *a" is
useful and no_sanitize("all") shouldn't cover that then no_unpoison_shadow
would have been better.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-12-05 8:18 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2022-12-04 6:38 [Bug c/107963] New: Support __attribute__((disable_sanitizer_instrumentation)) i at maskray dot me
2022-12-04 6:45 ` [Bug sanitizer/107963] " pinskia at gcc dot gnu.org
2022-12-04 21:50 ` sam at gentoo dot org
2022-12-04 23:24 ` i at maskray dot me
2022-12-05 0:01 ` pinskia at gcc dot gnu.org
2022-12-05 8:18 ` rguenth at gcc dot gnu.org
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