From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- drivers/base/regmap/Kconfig | 93 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 drivers/base/regmap/Kconfig (limited to 'drivers/base/regmap/Kconfig') diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig new file mode 100644 index 000000000..3c76a5bf6 --- /dev/null +++ b/drivers/base/regmap/Kconfig @@ -0,0 +1,93 @@ +# SPDX-License-Identifier: GPL-2.0 +# Generic register map support. There are no user servicable options here, +# this is an API intended to be used by other kernel subsystems. These +# subsystems should select the appropriate symbols. + +config REGMAP + bool + default y if (REGMAP_I2C || REGMAP_SLIMBUS || REGMAP_SPI || REGMAP_SPMI || REGMAP_W1 || REGMAP_AC97 || REGMAP_MMIO || REGMAP_IRQ || REGMAP_SOUNDWIRE || REGMAP_SOUNDWIRE_MBQ || REGMAP_SCCB || REGMAP_I3C || REGMAP_SPI_AVMM || REGMAP_MDIO || REGMAP_FSI) + help + Enable support for the Register Map (regmap) access API. + + Usually, this option is automatically selected when needed. + However, you may want to enable it manually for running the regmap + KUnit tests. + + If unsure, say N. + +config REGMAP_KUNIT + tristate "KUnit tests for regmap" + depends on KUNIT && REGMAP + default KUNIT_ALL_TESTS + select REGMAP_RAM + +config REGMAP_BUILD + bool "Enable regmap build" + depends on KUNIT + select REGMAP + help + This option exists purely to allow the regmap KUnit tests to + be enabled without having to enable some driver that uses + regmap due to unfortunate issues with how KUnit tests are + normally enabled. + +config REGMAP_AC97 + tristate + +config REGMAP_I2C + tristate + depends on I2C + +config REGMAP_SLIMBUS + tristate + depends on SLIMBUS + +config REGMAP_SPI + tristate + depends on SPI + +config REGMAP_SPMI + tristate + depends on SPMI + +config REGMAP_W1 + tristate + depends on W1 + +config REGMAP_MDIO + tristate + depends on PHYLIB + +config REGMAP_MMIO + tristate + +config REGMAP_IRQ + bool + select IRQ_DOMAIN + +config REGMAP_RAM + tristate + +config REGMAP_SOUNDWIRE + tristate + depends on SOUNDWIRE + +config REGMAP_SOUNDWIRE_MBQ + tristate + depends on SOUNDWIRE + +config REGMAP_SCCB + tristate + depends on I2C + +config REGMAP_I3C + tristate + depends on I3C + +config REGMAP_SPI_AVMM + tristate + depends on SPI + +config REGMAP_FSI + tristate + depends on FSI -- cgit v1.3.1