ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faultsgrafted

When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set,
a user fault may trigger show_pte() without any lock.
If another thread in the same process concurrently calls munmap(),
the page table pages may be freed while show_pte() is still traversing
them, causing a use-after-free in show_pte().

If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table
of PMD are freed when show_pte() is running.

Acquire mmap_write_lock() around show_pte() for user faults to fix the
contention.

For user faults, additionally restrict that show_pte() is called only
when the addr is a user-space address (addr < TASK_SIZE). This is because
the lock of tsk->mm only protects the virtual memory of user address space,
furthermore, dumping the page tables of a kernel-space address for user
faults is unnecessary and may have security implications.

Keep everything unchanged for kernel faults, because the kernel is
already in the "oops" state, acquiring a lock may risk a deadlock.

Co-developed-by: Qi Xi <xiqi2@huawei.com>

Fixes: 6d021b724481 ("ARM: dump pgd, pmd and pte states on unhandled data abort faults")
Link: https://lore.kernel.org/20260716014022.2823-1-xieyuanbin1@huawei.com
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Qi Xi <xiqi2@huawei.com>
Signed-off-by: Xie Yuanbin <xieyuanbin1@huawei.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 168 insertions, 0 deletions

diff --git a/include/trace/misc/rdma.h b/include/trace/misc/rdma.h
new file mode 100644
index 000000000..81bb454fc
--- /dev/null
+++ b/include/trace/misc/rdma.h
@@ -0,0 +1,168 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2017 Oracle.  All rights reserved.
+ */
+
+/*
+ * enum ib_event_type, from include/rdma/ib_verbs.h
+ */
+#define IB_EVENT_LIST				\
+	ib_event(CQ_ERR)			\
+	ib_event(QP_FATAL)			\
+	ib_event(QP_REQ_ERR)			\
+	ib_event(QP_ACCESS_ERR)			\
+	ib_event(COMM_EST)			\
+	ib_event(SQ_DRAINED)			\
+	ib_event(PATH_MIG)			\
+	ib_event(PATH_MIG_ERR)			\
+	ib_event(DEVICE_FATAL)			\
+	ib_event(PORT_ACTIVE)			\
+	ib_event(PORT_ERR)			\
+	ib_event(LID_CHANGE)			\
+	ib_event(PKEY_CHANGE)			\
+	ib_event(SM_CHANGE)			\
+	ib_event(SRQ_ERR)			\
+	ib_event(SRQ_LIMIT_REACHED)		\
+	ib_event(QP_LAST_WQE_REACHED)		\
+	ib_event(CLIENT_REREGISTER)		\
+	ib_event(GID_CHANGE)			\
+	ib_event_end(WQ_FATAL)
+
+#undef ib_event
+#undef ib_event_end
+
+#define ib_event(x)		TRACE_DEFINE_ENUM(IB_EVENT_##x);
+#define ib_event_end(x)		TRACE_DEFINE_ENUM(IB_EVENT_##x);
+
+IB_EVENT_LIST
+
+#undef ib_event
+#undef ib_event_end
+
+#define ib_event(x)		{ IB_EVENT_##x, #x },
+#define ib_event_end(x)		{ IB_EVENT_##x, #x }
+
+#define rdma_show_ib_event(x) \
+		__print_symbolic(x, IB_EVENT_LIST)
+
+/*
+ * enum ib_wc_status type, from include/rdma/ib_verbs.h
+ */
+#define IB_WC_STATUS_LIST			\
+	ib_wc_status(SUCCESS)			\
+	ib_wc_status(LOC_LEN_ERR)		\
+	ib_wc_status(LOC_QP_OP_ERR)		\
+	ib_wc_status(LOC_EEC_OP_ERR)		\
+	ib_wc_status(LOC_PROT_ERR)		\
+	ib_wc_status(WR_FLUSH_ERR)		\
+	ib_wc_status(MW_BIND_ERR)		\
+	ib_wc_status(BAD_RESP_ERR)		\
+	ib_wc_status(LOC_ACCESS_ERR)		\
+	ib_wc_status(REM_INV_REQ_ERR)		\
+	ib_wc_status(REM_ACCESS_ERR)		\
+	ib_wc_status(REM_OP_ERR)		\
+	ib_wc_status(RETRY_EXC_ERR)		\
+	ib_wc_status(RNR_RETRY_EXC_ERR)		\
+	ib_wc_status(LOC_RDD_VIOL_ERR)		\
+	ib_wc_status(REM_INV_RD_REQ_ERR)	\
+	ib_wc_status(REM_ABORT_ERR)		\
+	ib_wc_status(INV_EECN_ERR)		\
+	ib_wc_status(INV_EEC_STATE_ERR)		\
+	ib_wc_status(FATAL_ERR)			\
+	ib_wc_status(RESP_TIMEOUT_ERR)		\
+	ib_wc_status_end(GENERAL_ERR)
+
+#undef ib_wc_status
+#undef ib_wc_status_end
+
+#define ib_wc_status(x)		TRACE_DEFINE_ENUM(IB_WC_##x);
+#define ib_wc_status_end(x)	TRACE_DEFINE_ENUM(IB_WC_##x);
+
+IB_WC_STATUS_LIST
+
+#undef ib_wc_status
+#undef ib_wc_status_end
+
+#define ib_wc_status(x)		{ IB_WC_##x, #x },
+#define ib_wc_status_end(x)	{ IB_WC_##x, #x }
+
+#define rdma_show_wc_status(x) \
+		__print_symbolic(x, IB_WC_STATUS_LIST)
+
+/*
+ * enum ib_cm_event_type, from include/rdma/ib_cm.h
+ */
+#define IB_CM_EVENT_LIST			\
+	ib_cm_event(REQ_ERROR)			\
+	ib_cm_event(REQ_RECEIVED)		\
+	ib_cm_event(REP_ERROR)			\
+	ib_cm_event(REP_RECEIVED)		\
+	ib_cm_event(RTU_RECEIVED)		\
+	ib_cm_event(USER_ESTABLISHED)		\
+	ib_cm_event(DREQ_ERROR)			\
+	ib_cm_event(DREQ_RECEIVED)		\
+	ib_cm_event(DREP_RECEIVED)		\
+	ib_cm_event(TIMEWAIT_EXIT)		\
+	ib_cm_event(MRA_RECEIVED)		\
+	ib_cm_event(REJ_RECEIVED)		\
+	ib_cm_event(LAP_ERROR)			\
+	ib_cm_event(LAP_RECEIVED)		\
+	ib_cm_event(APR_RECEIVED)		\
+	ib_cm_event(SIDR_REQ_ERROR)		\
+	ib_cm_event(SIDR_REQ_RECEIVED)		\
+	ib_cm_event_end(SIDR_REP_RECEIVED)
+
+#undef ib_cm_event
+#undef ib_cm_event_end
+
+#define ib_cm_event(x)		TRACE_DEFINE_ENUM(IB_CM_##x);
+#define ib_cm_event_end(x)	TRACE_DEFINE_ENUM(IB_CM_##x);
+
+IB_CM_EVENT_LIST
+
+#undef ib_cm_event
+#undef ib_cm_event_end
+
+#define ib_cm_event(x)		{ IB_CM_##x, #x },
+#define ib_cm_event_end(x)	{ IB_CM_##x, #x }
+
+#define rdma_show_ib_cm_event(x) \
+		__print_symbolic(x, IB_CM_EVENT_LIST)
+
+/*
+ * enum rdma_cm_event_type, from include/rdma/rdma_cm.h
+ */
+#define RDMA_CM_EVENT_LIST			\
+	rdma_cm_event(ADDR_RESOLVED)		\
+	rdma_cm_event(ADDR_ERROR)		\
+	rdma_cm_event(ROUTE_RESOLVED)		\
+	rdma_cm_event(ROUTE_ERROR)		\
+	rdma_cm_event(CONNECT_REQUEST)		\
+	rdma_cm_event(CONNECT_RESPONSE)		\
+	rdma_cm_event(CONNECT_ERROR)		\
+	rdma_cm_event(UNREACHABLE)		\
+	rdma_cm_event(REJECTED)			\
+	rdma_cm_event(ESTABLISHED)		\
+	rdma_cm_event(DISCONNECTED)		\
+	rdma_cm_event(DEVICE_REMOVAL)		\
+	rdma_cm_event(MULTICAST_JOIN)		\
+	rdma_cm_event(MULTICAST_ERROR)		\
+	rdma_cm_event(ADDR_CHANGE)		\
+	rdma_cm_event_end(TIMEWAIT_EXIT)
+
+#undef rdma_cm_event
+#undef rdma_cm_event_end
+
+#define rdma_cm_event(x)	TRACE_DEFINE_ENUM(RDMA_CM_EVENT_##x);
+#define rdma_cm_event_end(x)	TRACE_DEFINE_ENUM(RDMA_CM_EVENT_##x);
+
+RDMA_CM_EVENT_LIST
+
+#undef rdma_cm_event
+#undef rdma_cm_event_end
+
+#define rdma_cm_event(x)	{ RDMA_CM_EVENT_##x, #x },
+#define rdma_cm_event_end(x)	{ RDMA_CM_EVENT_##x, #x }
+
+#define rdma_show_cm_event(x) \
+		__print_symbolic(x, RDMA_CM_EVENT_LIST)