On Mon, Sep 05, 2022 at 02:24:14PM +0200, Alexander Potapenko wrote: > +Here is an example of a KMSAN report:: > + > + ===================================================== > + BUG: KMSAN: uninit-value in test_uninit_kmsan_check_memory+0x1be/0x380 [kmsan_test] > + test_uninit_kmsan_check_memory+0x1be/0x380 mm/kmsan/kmsan_test.c:273 > + kunit_run_case_internal lib/kunit/test.c:333 > + kunit_try_run_case+0x206/0x420 lib/kunit/test.c:374 > + kunit_generic_run_threadfn_adapter+0x6d/0xc0 lib/kunit/try-catch.c:28 > + kthread+0x721/0x850 kernel/kthread.c:327 > + ret_from_fork+0x1f/0x30 ??:? > + > + Uninit was stored to memory at: > + do_uninit_local_array+0xfa/0x110 mm/kmsan/kmsan_test.c:260 > + test_uninit_kmsan_check_memory+0x1a2/0x380 mm/kmsan/kmsan_test.c:271 > + kunit_run_case_internal lib/kunit/test.c:333 > + kunit_try_run_case+0x206/0x420 lib/kunit/test.c:374 > + kunit_generic_run_threadfn_adapter+0x6d/0xc0 lib/kunit/try-catch.c:28 > + kthread+0x721/0x850 kernel/kthread.c:327 > + ret_from_fork+0x1f/0x30 ??:? > + > + Local variable uninit created at: > + do_uninit_local_array+0x4a/0x110 mm/kmsan/kmsan_test.c:256 > + test_uninit_kmsan_check_memory+0x1a2/0x380 mm/kmsan/kmsan_test.c:271 > + > + Bytes 4-7 of 8 are uninitialized > + Memory access of size 8 starts at ffff888083fe3da0 > + > + CPU: 0 PID: 6731 Comm: kunit_try_catch Tainted: G B E 5.16.0-rc3+ #104 > + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 > + ===================================================== Are these table markers in the code block above part of kmsan output? > +A use of uninitialized value ``v`` is reported by KMSAN in the following cases: > + - in a condition, e.g. ``if (v) { ... }``; > + - in an indexing or pointer dereferencing, e.g. ``array[v]`` or ``*v``; > + - when it is copied to userspace or hardware, e.g. ``copy_to_user(..., &v, ...)``; > + - when it is passed as an argument to a function, and > + ``CONFIG_KMSAN_CHECK_PARAM_RETVAL`` is enabled (see below). The sentence before the list above is rendered as definition list term instead, so I add the blank line separator: ---- >8 ---- diff --git a/Documentation/dev-tools/kmsan.rst b/Documentation/dev-tools/kmsan.rst index 2a53a801198cbf..55fa82212eb255 100644 --- a/Documentation/dev-tools/kmsan.rst +++ b/Documentation/dev-tools/kmsan.rst @@ -67,6 +67,7 @@ uninitialized in the local variable, as well as the stack where the value was copied to another memory location before use. A use of uninitialized value ``v`` is reported by KMSAN in the following cases: + - in a condition, e.g. ``if (v) { ... }``; - in an indexing or pointer dereferencing, e.g. ``array[v]`` or ``*v``; - when it is copied to userspace or hardware, e.g. ``copy_to_user(..., &v, ...)``; Thanks. -- An old man doll... just what I always wanted! - Clara
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