From: andrey.konovalov@linux.dev
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>,
Marco Elver <elver@google.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
kasan-dev@googlegroups.com, Will Deacon <will@kernel.org>,
Sami Tolvanen <samitolvanen@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH mm 2/2] kasan, scs: support tagged vmalloc mappings
Date: Wed, 2 Mar 2022 16:13:31 +0100 [thread overview]
Message-ID: <2f6605e3a358cf64d73a05710cb3da356886ad29.1646233925.git.andreyknvl@google.com> (raw)
In-Reply-To: <9230ca3d3e40ffca041c133a524191fd71969a8d.1646233925.git.andreyknvl@google.com>
From: Andrey Konovalov <andreyknvl@google.com>
Fix up the custom KASAN instrumentation for Shadow Call Stack to support
vmalloc() mappings and pointers being tagged.
- Use the tagged pointer returned by kasan_unpoison_vmalloc() in
__scs_alloc() when calling memset() to avoid false-positives.
- Do not return a tagged Shadow Call Stack pointer from __scs_alloc(),
as this might lead to conflicts with the instrumentation.
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
Andrew, please put this patch after
"kasan, vmalloc: only tag normal vmalloc allocations".
---
kernel/scs.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/kernel/scs.c b/kernel/scs.c
index 1033a76a3284..b7e1b096d906 100644
--- a/kernel/scs.c
+++ b/kernel/scs.c
@@ -32,16 +32,19 @@ static void *__scs_alloc(int node)
for (i = 0; i < NR_CACHED_SCS; i++) {
s = this_cpu_xchg(scs_cache[i], NULL);
if (s) {
- kasan_unpoison_vmalloc(s, SCS_SIZE,
- KASAN_VMALLOC_PROT_NORMAL);
+ s = kasan_unpoison_vmalloc(s, SCS_SIZE,
+ KASAN_VMALLOC_PROT_NORMAL);
memset(s, 0, SCS_SIZE);
- return s;
+ goto out;
}
}
- return __vmalloc_node_range(SCS_SIZE, 1, VMALLOC_START, VMALLOC_END,
+ s = __vmalloc_node_range(SCS_SIZE, 1, VMALLOC_START, VMALLOC_END,
GFP_SCS, PAGE_KERNEL, 0, node,
__builtin_return_address(0));
+
+out:
+ return kasan_reset_tag(s);
}
void *scs_alloc(int node)
--
2.25.1
prev parent reply other threads:[~2022-03-02 15:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-02 15:13 [PATCH mm 1/2] fix for "kasan, vmalloc: only tag normal vmalloc allocations" andrey.konovalov
2022-03-02 15:13 ` andrey.konovalov [this message]
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