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Revision f2d7b53c0153f2daa8bc8f1ff29b5a1e03a36458 authored by Alexander Potapenko on 02 November 2022, 10:15:00 UTC, committed by Alexander Potapenko on 02 November 2022, 10:55:06 UTC 
x86/traps: avoid KMSAN bugs originating from handle_bug()
 
There is a case in exc_invalid_op handler that is executed outside the
irqentry_enter()/irqentry_exit() region when an UD2 instruction is used
to encode a call to __warn().

In that case the `struct pt_regs` passed to the interrupt handler is
never unpoisoned by KMSAN (this is normally done in irqentry_enter()),
which leads to false positives inside handle_bug().

Use kmsan_unpoison_entry_regs() to explicitly unpoison those registers
before using them.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Signed-off-by: Alexander Potapenko <glider@google.com>
1 parent 4dbc4d5
Raw File
tctx.h 
// SPDX-License-Identifier: GPL-2.0

struct io_tctx_node {
	struct list_head	ctx_node;
	struct task_struct	*task;
	struct io_ring_ctx	*ctx;
};

int io_uring_alloc_task_context(struct task_struct *task,
				struct io_ring_ctx *ctx);
void io_uring_del_tctx_node(unsigned long index);
int __io_uring_add_tctx_node(struct io_ring_ctx *ctx);
int __io_uring_add_tctx_node_from_submit(struct io_ring_ctx *ctx);
void io_uring_clean_tctx(struct io_uring_task *tctx);

void io_uring_unreg_ringfd(void);
int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg,
		       unsigned nr_args);
int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg,
			 unsigned nr_args);

/*
 * Note that this task has used io_uring. We use it for cancelation purposes.
 */
static inline int io_uring_add_tctx_node(struct io_ring_ctx *ctx)
{
	struct io_uring_task *tctx = current->io_uring;

	if (likely(tctx && tctx->last == ctx))
		return 0;

	return __io_uring_add_tctx_node_from_submit(ctx);
}
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