x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

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) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 257 insertions, 0 deletions

diff --git a/drivers/ata/libata-trace.c b/drivers/ata/libata-trace.c
new file mode 100644
index 000000000..9b5363fd0
--- /dev/null
+++ b/drivers/ata/libata-trace.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * libata-trace.c - trace functions for libata
+ *
+ * Copyright 2015 Hannes Reinecke
+ * Copyright 2015 SUSE Linux GmbH
+ */
+
+#include <linux/kernel.h>
+#include <linux/trace_seq.h>
+#include <trace/events/libata.h>
+
+const char *
+libata_trace_parse_status(struct trace_seq *p, unsigned char status)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "{ ");
+	if (status & ATA_BUSY)
+		trace_seq_printf(p, "BUSY ");
+	if (status & ATA_DRDY)
+		trace_seq_printf(p, "DRDY ");
+	if (status & ATA_DF)
+		trace_seq_printf(p, "DF ");
+	if (status & ATA_DSC)
+		trace_seq_printf(p, "DSC ");
+	if (status & ATA_DRQ)
+		trace_seq_printf(p, "DRQ ");
+	if (status & ATA_CORR)
+		trace_seq_printf(p, "CORR ");
+	if (status & ATA_SENSE)
+		trace_seq_printf(p, "SENSE ");
+	if (status & ATA_ERR)
+		trace_seq_printf(p, "ERR ");
+	trace_seq_putc(p, '}');
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+
+const char *
+libata_trace_parse_host_stat(struct trace_seq *p, unsigned char host_stat)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "{ ");
+	if (host_stat & ATA_DMA_INTR)
+		trace_seq_printf(p, "INTR ");
+	if (host_stat & ATA_DMA_ERR)
+		trace_seq_printf(p, "ERR ");
+	if (host_stat & ATA_DMA_ACTIVE)
+		trace_seq_printf(p, "ACTIVE ");
+	trace_seq_putc(p, '}');
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+
+const char *
+libata_trace_parse_eh_action(struct trace_seq *p, unsigned int eh_action)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "%x", eh_action);
+	if (eh_action) {
+		trace_seq_printf(p, "{ ");
+		if (eh_action & ATA_EH_REVALIDATE)
+			trace_seq_printf(p, "REVALIDATE ");
+		if (eh_action & (ATA_EH_SOFTRESET | ATA_EH_HARDRESET))
+			trace_seq_printf(p, "RESET ");
+		else if (eh_action & ATA_EH_SOFTRESET)
+			trace_seq_printf(p, "SOFTRESET ");
+		else if (eh_action & ATA_EH_HARDRESET)
+			trace_seq_printf(p, "HARDRESET ");
+		if (eh_action & ATA_EH_ENABLE_LINK)
+			trace_seq_printf(p, "ENABLE_LINK ");
+		if (eh_action & ATA_EH_PARK)
+			trace_seq_printf(p, "PARK ");
+		trace_seq_putc(p, '}');
+	}
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+
+const char *
+libata_trace_parse_eh_err_mask(struct trace_seq *p, unsigned int eh_err_mask)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "%x", eh_err_mask);
+	if (eh_err_mask) {
+		trace_seq_printf(p, "{ ");
+		if (eh_err_mask & AC_ERR_DEV)
+			trace_seq_printf(p, "DEV ");
+		if (eh_err_mask & AC_ERR_HSM)
+			trace_seq_printf(p, "HSM ");
+		if (eh_err_mask & AC_ERR_TIMEOUT)
+			trace_seq_printf(p, "TIMEOUT ");
+		if (eh_err_mask & AC_ERR_MEDIA)
+			trace_seq_printf(p, "MEDIA ");
+		if (eh_err_mask & AC_ERR_ATA_BUS)
+			trace_seq_printf(p, "ATA_BUS ");
+		if (eh_err_mask & AC_ERR_HOST_BUS)
+			trace_seq_printf(p, "HOST_BUS ");
+		if (eh_err_mask & AC_ERR_SYSTEM)
+			trace_seq_printf(p, "SYSTEM ");
+		if (eh_err_mask & AC_ERR_INVALID)
+			trace_seq_printf(p, "INVALID ");
+		if (eh_err_mask & AC_ERR_OTHER)
+			trace_seq_printf(p, "OTHER ");
+		if (eh_err_mask & AC_ERR_NODEV_HINT)
+			trace_seq_printf(p, "NODEV_HINT ");
+		if (eh_err_mask & AC_ERR_NCQ)
+			trace_seq_printf(p, "NCQ ");
+		trace_seq_putc(p, '}');
+	}
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+
+const char *
+libata_trace_parse_qc_flags(struct trace_seq *p, unsigned int qc_flags)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "%x", qc_flags);
+	if (qc_flags) {
+		trace_seq_printf(p, "{ ");
+		if (qc_flags & ATA_QCFLAG_ACTIVE)
+			trace_seq_printf(p, "ACTIVE ");
+		if (qc_flags & ATA_QCFLAG_DMAMAP)
+			trace_seq_printf(p, "DMAMAP ");
+		if (qc_flags & ATA_QCFLAG_IO)
+			trace_seq_printf(p, "IO ");
+		if (qc_flags & ATA_QCFLAG_RESULT_TF)
+			trace_seq_printf(p, "RESULT_TF ");
+		if (qc_flags & ATA_QCFLAG_CLEAR_EXCL)
+			trace_seq_printf(p, "CLEAR_EXCL ");
+		if (qc_flags & ATA_QCFLAG_QUIET)
+			trace_seq_printf(p, "QUIET ");
+		if (qc_flags & ATA_QCFLAG_RETRY)
+			trace_seq_printf(p, "RETRY ");
+		if (qc_flags & ATA_QCFLAG_EH)
+			trace_seq_printf(p, "FAILED ");
+		if (qc_flags & ATA_QCFLAG_SENSE_VALID)
+			trace_seq_printf(p, "SENSE_VALID ");
+		if (qc_flags & ATA_QCFLAG_EH_SCHEDULED)
+			trace_seq_printf(p, "EH_SCHEDULED ");
+		trace_seq_putc(p, '}');
+	}
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+
+const char *
+libata_trace_parse_tf_flags(struct trace_seq *p, unsigned int tf_flags)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "%x", tf_flags);
+	if (tf_flags) {
+		trace_seq_printf(p, "{ ");
+		if (tf_flags & ATA_TFLAG_LBA48)
+			trace_seq_printf(p, "LBA48 ");
+		if (tf_flags & ATA_TFLAG_ISADDR)
+			trace_seq_printf(p, "ISADDR ");
+		if (tf_flags & ATA_TFLAG_DEVICE)
+			trace_seq_printf(p, "DEV ");
+		if (tf_flags & ATA_TFLAG_WRITE)
+			trace_seq_printf(p, "WRITE ");
+		if (tf_flags & ATA_TFLAG_LBA)
+			trace_seq_printf(p, "LBA ");
+		if (tf_flags & ATA_TFLAG_FUA)
+			trace_seq_printf(p, "FUA ");
+		if (tf_flags & ATA_TFLAG_POLLING)
+			trace_seq_printf(p, "POLL ");
+		trace_seq_putc(p, '}');
+	}
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+
+const char *
+libata_trace_parse_subcmd(struct trace_seq *p, unsigned char cmd,
+			  unsigned char feature, unsigned char hob_nsect)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	switch (cmd) {
+	case ATA_CMD_FPDMA_RECV:
+		switch (hob_nsect & 0x5f) {
+		case ATA_SUBCMD_FPDMA_RECV_RD_LOG_DMA_EXT:
+			trace_seq_printf(p, " READ_LOG_DMA_EXT");
+			break;
+		case ATA_SUBCMD_FPDMA_RECV_ZAC_MGMT_IN:
+			trace_seq_printf(p, " ZAC_MGMT_IN");
+			break;
+		}
+		break;
+	case ATA_CMD_FPDMA_SEND:
+		switch (hob_nsect & 0x5f) {
+		case ATA_SUBCMD_FPDMA_SEND_WR_LOG_DMA_EXT:
+			trace_seq_printf(p, " WRITE_LOG_DMA_EXT");
+			break;
+		case ATA_SUBCMD_FPDMA_SEND_DSM:
+			trace_seq_printf(p, " DATASET_MANAGEMENT");
+			break;
+		}
+		break;
+	case ATA_CMD_NCQ_NON_DATA:
+		switch (feature) {
+		case ATA_SUBCMD_NCQ_NON_DATA_ABORT_QUEUE:
+			trace_seq_printf(p, " ABORT_QUEUE");
+			break;
+		case ATA_SUBCMD_NCQ_NON_DATA_SET_FEATURES:
+			trace_seq_printf(p, " SET_FEATURES");
+			break;
+		case ATA_SUBCMD_NCQ_NON_DATA_ZERO_EXT:
+			trace_seq_printf(p, " ZERO_EXT");
+			break;
+		case ATA_SUBCMD_NCQ_NON_DATA_ZAC_MGMT_OUT:
+			trace_seq_printf(p, " ZAC_MGMT_OUT");
+			break;
+		}
+		break;
+	case ATA_CMD_ZAC_MGMT_IN:
+		switch (feature) {
+		case ATA_SUBCMD_ZAC_MGMT_IN_REPORT_ZONES:
+			trace_seq_printf(p, " REPORT_ZONES");
+			break;
+		}
+		break;
+	case ATA_CMD_ZAC_MGMT_OUT:
+		switch (feature) {
+		case ATA_SUBCMD_ZAC_MGMT_OUT_CLOSE_ZONE:
+			trace_seq_printf(p, " CLOSE_ZONE");
+			break;
+		case ATA_SUBCMD_ZAC_MGMT_OUT_FINISH_ZONE:
+			trace_seq_printf(p, " FINISH_ZONE");
+			break;
+		case ATA_SUBCMD_ZAC_MGMT_OUT_OPEN_ZONE:
+			trace_seq_printf(p, " OPEN_ZONE");
+			break;
+		case ATA_SUBCMD_ZAC_MGMT_OUT_RESET_WRITE_POINTER:
+			trace_seq_printf(p, " RESET_WRITE_POINTER");
+			break;
+		}
+		break;
+	}
+	trace_seq_putc(p, 0);
+
+	return ret;
+}