From: Dave Hansen <dave.hansen@intel.com>
To: Alexander Potapenko <glider@google.com>
Cc: elver@google.com, dvyukov@google.com,
dave.hansen@linux.intel.com, peterz@infradead.org,
akpm@linux-foundation.org, x86@kernel.org,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH 1/3] x86: mm: disable KMSAN instrumentation for physaddr.c
Date: Fri, 21 Jun 2024 09:40:25 -0700 [thread overview]
Message-ID: <a2e7b9a1-15ff-41c3-a6b9-bdab4ead904b@intel.com> (raw)
In-Reply-To: <20240621094901.1360454-1-glider@google.com>
On 6/21/24 02:48, Alexander Potapenko wrote:
> Enabling CONFIG_DEBUG_VIRTUAL=y together with KMSAN led to infinite
> recursion, because kmsan_get_metadata() ended up calling instrumented
> __pfn_valid() from arch/x86/mm/physaddr.c.
>
> Prevent it by disabling instrumentation of the whole file.
This does seem rather ad-hoc. It's the same basic reason we have
"noinstr": code instrumentation infrastructure uses generally can't be
instrumented itself.
How hard would it be to make sure that kmsan_get_metadata() and friends
don't call any symbols that were compiled with -fsanitize=kernel-memory?
I do also think I'd much rather see __no_kmsan_checks on the functions
than doing whole files. I *guarantee* if code gets moved around that
whoever does it will miss the KMSAN_SANITIZE_physaddr.o in the makefile.
prev parent reply other threads:[~2024-06-21 16:40 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-21 9:48 [PATCH 1/3] x86: mm: disable KMSAN instrumentation for physaddr.c Alexander Potapenko
2024-06-21 9:49 ` [PATCH 2/3] lib/Kconfig.debug: disable LOCK_DEBUGGING_SUPPORT under KMSAN Alexander Potapenko
2024-06-21 15:02 ` Kirill A . Shutemov
2024-06-21 16:16 ` Dave Hansen
2024-06-21 16:23 ` Dave Hansen
2024-06-25 18:51 ` Boqun Feng
2024-06-25 19:06 ` Paul E. McKenney
2024-06-25 19:37 ` Boqun Feng
2024-06-26 8:35 ` Alexander Potapenko
2024-06-21 9:49 ` [PATCH 3/3] x86/traps: fix an objtool warning in handle_bug() Alexander Potapenko
2024-06-21 15:09 ` Kirill A . Shutemov
2024-06-21 14:57 ` [PATCH 1/3] x86: mm: disable KMSAN instrumentation for physaddr.c Kirill A . Shutemov
2024-06-21 16:40 ` Dave Hansen [this message]
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