diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/dev-tools/kasan.rst | 17 | ||||
| -rw-r--r-- | Documentation/vm/page_owner.rst | 65 |
2 files changed, 70 insertions, 12 deletions
diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index 8089c559d339..7614a1fc30fa 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -30,7 +30,7 @@ Software tag-based KASAN mode is only supported in Clang. 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 disabling KASAN or controlling features: 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 match-all pointer tag (accesses through 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 match-all pointer tag (accesses through 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. diff --git a/Documentation/vm/page_owner.rst b/Documentation/vm/page_owner.rst index 905555e3e483..c4de6f8dabe9 100644 --- a/Documentation/vm/page_owner.rst +++ b/Documentation/vm/page_owner.rst @@ -78,7 +78,7 @@ Usage 2) Enable page owner: add "page_owner=on" to boot cmdline. -3) Do the job what you want to debug +3) Do the job that you want to debug. 4) Analyze information from page owner:: @@ -89,22 +89,75 @@ Usage Page allocated via order XXX, ... PFN XXX ... - // Detailed stack + // Detailed stack Page allocated via order XXX, ... PFN XXX ... - // Detailed stack + // Detailed stack The ``page_owner_sort`` tool ignores ``PFN`` rows, puts the remaining rows in buf, uses regexp to extract the page order value, counts the times - and pages of buf, and finally sorts them according to the times. + and pages of buf, and finally sorts them according to the parameter(s). See the result about who allocated each page in the ``sorted_page_owner.txt``. General output:: XXX times, XXX pages: Page allocated via order XXX, ... - // Detailed stack + // Detailed stack By default, ``page_owner_sort`` is sorted according to the times of buf. - If you want to sort by the pages nums of buf, use the ``-m`` parameter. + If you want to sort by the page nums of buf, use the ``-m`` parameter. + The detailed parameters are: + + fundamental function: + + Sort: + -a Sort by memory allocation time. + -m Sort by total memory. + -p Sort by pid. + -P Sort by tgid. + -n Sort by task command name. + -r Sort by memory release time. + -s Sort by stack trace. + -t Sort by times (default). + + additional function: + + Cull: + -c Cull by comparing stacktrace instead of total block. + --cull <rules> + Specify culling rules.Culling syntax is key[,key[,...]].Choose a + multi-letter key from the **STANDARD FORMAT SPECIFIERS** section. + + + <rules> is a single argument in the form of a comma-separated list, + which offers a way to specify individual culling rules. The recognized + keywords are described in the **STANDARD FORMAT SPECIFIERS** section below. + <rules> can be specified by the sequence of keys k1,k2, ..., as described in + the STANDARD SORT KEYS section below. Mixed use of abbreviated and + complete-form of keys is allowed. + + + Examples: + ./page_owner_sort <input> <output> --cull=stacktrace + ./page_owner_sort <input> <output> --cull=st,pid,name + ./page_owner_sort <input> <output> --cull=n,f + + Filter: + -f Filter out the information of blocks whose memory has been released. + + Select: + --pid <PID> Select by pid. + --tgid <TGID> Select by tgid. + --name <command> Select by task command name. + +STANDARD FORMAT SPECIFIERS +========================== + + KEY LONG DESCRIPTION + p pid process ID + tg tgid thread group ID + n name task command name + f free whether the page has been released or not + st stacktrace stace trace of the page allocation |