summaryrefslogtreecommitdiffstats
path: root/Documentation/dev-tools/ubsan.rst
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
commitcf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch)
tree757a3d280760c654767631cab5ad8af2d86d1848 /Documentation/dev-tools/ubsan.rst
downloadlinux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.tar.gz
linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.zip
Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij: "Core changes: - Use the non-blocking mux_state_try_select() in the generic MUX pin control back-end - Free pin maps on pinctrl_generic_to_map() failure in the core helpers New hardware pin control: - Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC (this is for the low power audio, LPASS = Low Power Audio SubSystem portions) - Upboard support on top of the Intel pin controller - Apple T6030 and T6031 support (just compatible strings) - Samsung Exynos 8855 SoC - Mediatek MT6858 SoC - Rockchip RK3308B and RV1106 SoCs - Airoha EN7523 and AN7563 SoCs Improvements: - Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable - Qualcomm improvements on top of the Qualcomm PDC (power domain controller) irqchip improvements from tglx:s tree - Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups - The NPCM8xx driver has been put into shape fixing many pin and group definitions - Some non-urgent Tegra 264 pin assignments are fixed up - Some non-urgent fixups to Airoha AN7581 and AN7583 registers and pin assignments, missing features etc" * tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits) dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema pinctrl: meson: sync some modify from A4 pinctrl: meson: a4: Add input enable pin configuration pinctrl: realtek: rtd1625: remove unused group name spdif_sel pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13 dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema Revert "Merge branch 'ib-rsk7204' into devel" pinctrl: rockchip: Add RV1106 pinctrl support dt-bindings: pinctrl: rockchip: Add RV1106 compatible pinctrl: rockchip: Decode drive strength in the get function pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable pinctrl: airoha: add support of an7563 SoC dt-bindings: pinctrl: airoha: add support of an7563 pin controller pinctrl: airoha: try to find chip scu node by phandle first pinctrl: airoha: add support of en7523 SoC dt-bindings: pinctrl: airoha: add support of en7523 pin controller pinctrl: airoha: an7583: add support for olt pinmux pinctrl: airoha: an7583: add support for pon_alt pinmux pinctrl: airoha: an7583: add support for npu_uart pinmux dt-bindings: pinctrl: airoha: an7583: add missed features ...
Diffstat (limited to 'Documentation/dev-tools/ubsan.rst')
-rw-r--r--Documentation/dev-tools/ubsan.rst79
1 files changed, 79 insertions, 0 deletions
diff --git a/Documentation/dev-tools/ubsan.rst b/Documentation/dev-tools/ubsan.rst
new file mode 100644
index 000000000..e3591f8e9
--- /dev/null
+++ b/Documentation/dev-tools/ubsan.rst
@@ -0,0 +1,79 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Undefined Behavior Sanitizer - UBSAN
+====================================
+
+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 the kernel with::
+
+ CONFIG_UBSAN=y
+
+To exclude files from being instrumented use::
+
+ UBSAN_SANITIZE_main.o := n
+
+and to exclude all targets in one directory use::
+
+ UBSAN_SANITIZE := n
+
+When disabled for all targets, specific files can be enabled using::
+
+ UBSAN_SANITIZE_main.o := y
+
+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
+.. _3: https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html