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kasan-documentation-updates.patch removed from -mm tree

merged Andrew Morton 1 participant 1 message Mar 25, 2022

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The patch titled
Subject: kasan: documentation updates
has been removed from the -mm tree. Its filename was
kasan-documentation-updates.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Andrey Konovalov <[email protected]>
Subject: kasan: documentation updates

Update KASAN documentation:

- Bump Clang version requirement for HW_TAGS as ARM64_MTE depends on AS_HAS_LSE_ATOMICS as of commit 2decad92f4731 ("arm64: mte: Ensure TIF_MTE_ASYNC_FAULT is set atomically"), which requires Clang 12.
- Add description of the new kasan.vmalloc command line flag.
- Mention that SW_TAGS and HW_TAGS modes now support vmalloc tagging.
- Explicitly say that the "Shadow memory" section is only applicable to software KASAN modes.
- Mention that shadow-based KASAN_VMALLOC is supported on arm64.

---

 Documentation/dev-tools/kasan.rst |   17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)
Documentation/dev-tools/kasan.rst renamed from Documentation/dev-tools/kasan.rst~kasan-documentation-updates +11 -6
@@ -30,7 +30,7 @@ Software tag-based KASAN mode is only su
 
 The hardware KASAN mode (#3) relies on hardware to perform the checks but
 still requires a compiler version that supports memory tagging instructions.
-This mode is supported in GCC 10+ and Clang 11+.
+This mode is supported in GCC 10+ and Clang 12+.
 
 Both software KASAN modes work with SLUB and SLAB memory allocators,
 while the hardware tag-based KASAN currently only supports SLUB.
@@ -206,6 +206,9 @@ additional boot parameters that allow di
   Asymmetric mode: a bad access is detected synchronously on reads and
   asynchronously on writes.
 
+- ``kasan.vmalloc=off`` or ``=on`` disables or enables tagging of vmalloc
+  allocations (default: ``on``).
+
 - ``kasan.stacktrace=off`` or ``=on`` disables or enables alloc and free stack
   traces collection (default: ``on``).
 
@@ -279,8 +282,8 @@ Software tag-based KASAN uses 0xFF as a
 pointers with the 0xFF pointer tag are not checked). The value 0xFE is currently
 reserved to tag freed memory regions.
 
-Software tag-based KASAN currently only supports tagging of slab and page_alloc
-memory.
+Software tag-based KASAN currently only supports tagging of slab, page_alloc,
+and vmalloc memory.
 
 Hardware tag-based KASAN
 ~~~~~~~~~~~~~~~~~~~~~~~~
@@ -303,8 +306,8 @@ Hardware tag-based KASAN uses 0xFF as a
 pointers with the 0xFF pointer tag are not checked). The value 0xFE is currently
 reserved to tag freed memory regions.
 
-Hardware tag-based KASAN currently only supports tagging of slab and page_alloc
-memory.
+Hardware tag-based KASAN currently only supports tagging of slab, page_alloc,
+and VM_ALLOC-based vmalloc memory.
 
 If the hardware does not support MTE (pre ARMv8.5), hardware tag-based KASAN
 will not be enabled. In this case, all KASAN boot parameters are ignored.
@@ -319,6 +322,8 @@ checking gets disabled.
 Shadow memory
 -------------
 
+The contents of this section are only applicable to software KASAN modes.
+
 The kernel maps memory in several different parts of the address space.
 The range of kernel virtual addresses is large: there is not enough real
 memory to support a real shadow region for every address that could be
@@ -349,7 +354,7 @@ CONFIG_KASAN_VMALLOC
 
 With ``CONFIG_KASAN_VMALLOC``, KASAN can cover vmalloc space at the
 cost of greater memory usage. Currently, this is supported on x86,
-riscv, s390, and powerpc.
+arm64, riscv, s390, and powerpc.
 
 This works by hooking into vmalloc and vmap and dynamically
 allocating real shadow memory to back the mappings.

_

Patches currently in -mm which might be from [email protected] are

stacktrace-add-interface-based-on-shadow-call-stack.patch arm64-scs-save-scs_sp-values-per-cpu-when-switching-stacks.patch arm64-implement-stack_trace_save_shadow.patch kasan-use-stack_trace_save_shadow.patch