diff options
| author | Jonathan Corbet <corbet@lwn.net> | 2016-08-07 21:35:42 (GMT) |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2016-08-18 23:41:51 (GMT) |
| commit | 1ead009cd622bc4c3c2cf1036d8e71d7f063838e (patch) | |
| tree | 140ef5dfe5d551362f67de82028bad67d7937871 /Documentation/ubsan.txt | |
| parent | 2757aafad9ee7b8740042e5540b59422337344ab (diff) | |
| download | linux-1ead009cd622bc4c3c2cf1036d8e71d7f063838e.tar.xz | |
docs: sphinxify ubsan.txt and move it to dev-tools
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/ubsan.txt')
| -rw-r--r-- | Documentation/ubsan.txt | 84 |
1 files changed, 0 insertions, 84 deletions
diff --git a/Documentation/ubsan.txt b/Documentation/ubsan.txt deleted file mode 100644 index f58215e..0000000 --- a/Documentation/ubsan.txt +++ /dev/null @@ -1,84 +0,0 @@ -Undefined Behavior Sanitizer - UBSAN - -Overview --------- - -UBSAN is a runtime undefined behaviour checker. - -UBSAN uses compile-time instrumentation to catch undefined behavior (UB). -Compiler inserts code that perform certain kinds of checks before operations -that may cause UB. If check fails (i.e. UB detected) __ubsan_handle_* -function called to print error message. - -GCC has that feature since 4.9.x [1] (see -fsanitize=undefined option and -its suboptions). GCC 5.x has more checkers implemented [2]. - -Report example ---------------- - - ================================================================================ - UBSAN: Undefined behaviour in ../include/linux/bitops.h:110:33 - shift exponent 32 is to large for 32-bit type 'unsigned int' - CPU: 0 PID: 0 Comm: swapper Not tainted 4.4.0-rc1+ #26 - 0000000000000000 ffffffff82403cc8 ffffffff815e6cd6 0000000000000001 - ffffffff82403cf8 ffffffff82403ce0 ffffffff8163a5ed 0000000000000020 - ffffffff82403d78 ffffffff8163ac2b ffffffff815f0001 0000000000000002 - Call Trace: - [<ffffffff815e6cd6>] dump_stack+0x45/0x5f - [<ffffffff8163a5ed>] ubsan_epilogue+0xd/0x40 - [<ffffffff8163ac2b>] __ubsan_handle_shift_out_of_bounds+0xeb/0x130 - [<ffffffff815f0001>] ? radix_tree_gang_lookup_slot+0x51/0x150 - [<ffffffff8173c586>] _mix_pool_bytes+0x1e6/0x480 - [<ffffffff83105653>] ? dmi_walk_early+0x48/0x5c - [<ffffffff8173c881>] add_device_randomness+0x61/0x130 - [<ffffffff83105b35>] ? dmi_save_one_device+0xaa/0xaa - [<ffffffff83105653>] dmi_walk_early+0x48/0x5c - [<ffffffff831066ae>] dmi_scan_machine+0x278/0x4b4 - [<ffffffff8111d58a>] ? vprintk_default+0x1a/0x20 - [<ffffffff830ad120>] ? early_idt_handler_array+0x120/0x120 - [<ffffffff830b2240>] setup_arch+0x405/0xc2c - [<ffffffff830ad120>] ? early_idt_handler_array+0x120/0x120 - [<ffffffff830ae053>] start_kernel+0x83/0x49a - [<ffffffff830ad120>] ? early_idt_handler_array+0x120/0x120 - [<ffffffff830ad386>] x86_64_start_reservations+0x2a/0x2c - [<ffffffff830ad4f3>] x86_64_start_kernel+0x16b/0x17a - ================================================================================ - -Usage ------ - -To enable UBSAN configure kernel with: - - CONFIG_UBSAN=y - -and to check the entire kernel: - - CONFIG_UBSAN_SANITIZE_ALL=y - -To enable instrumentation for specific files or directories, add a line -similar to the following to the respective kernel Makefile: - - For a single file (e.g. main.o): - UBSAN_SANITIZE_main.o := y - - For all files in one directory: - UBSAN_SANITIZE := y - -To exclude files from being instrumented even if -CONFIG_UBSAN_SANITIZE_ALL=y, use: - - UBSAN_SANITIZE_main.o := n - and: - UBSAN_SANITIZE := n - -Detection of unaligned accesses controlled through the separate option - -CONFIG_UBSAN_ALIGNMENT. It's off by default on architectures that support -unaligned accesses (CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y). One could -still enable it in config, just note that it will produce a lot of UBSAN -reports. - -References ----------- - -[1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html -[2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html |