Revision b90d72a6bfdb5e5c62cd223a8cdf4045bfbcb94d authored by Will Deacon on 12 January 2021, 22:18:55 UTC, committed by Catalin Marinas on 13 January 2021, 15:08:41 UTC
This reverts commit 367c820ef08082e68df8a3bc12e62393af21e4b5.

lockup_detector_init() makes heavy use of per-cpu variables and must be
called with preemption disabled. Usually, it's handled early during boot
in kernel_init_freeable(), before SMP has been initialised.

Since we do not know whether or not our PMU interrupt can be signalled
as an NMI until considerably later in the boot process, the Arm PMU
driver attempts to re-initialise the lockup detector off the back of a
device_initcall(). Unfortunately, this is called from preemptible
context and results in the following splat:

  | BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
  | caller is debug_smp_processor_id+0x20/0x2c
  | CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.10.0+ #276
  | Hardware name: linux,dummy-virt (DT)
  | Call trace:
  |   dump_backtrace+0x0/0x3c0
  |   show_stack+0x20/0x6c
  |   dump_stack+0x2f0/0x42c
  |   check_preemption_disabled+0x1cc/0x1dc
  |   debug_smp_processor_id+0x20/0x2c
  |   hardlockup_detector_event_create+0x34/0x18c
  |   hardlockup_detector_perf_init+0x2c/0x134
  |   watchdog_nmi_probe+0x18/0x24
  |   lockup_detector_init+0x44/0xa8
  |   armv8_pmu_driver_init+0x54/0x78
  |   do_one_initcall+0x184/0x43c
  |   kernel_init_freeable+0x368/0x380
  |   kernel_init+0x1c/0x1cc
  |   ret_from_fork+0x10/0x30

Rather than bodge this with raw_smp_processor_id() or randomly disabling
preemption, simply revert the culprit for now until we figure out how to
do this properly.

Reported-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Sumit Garg <sumit.garg@linaro.org>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/r/20201221162249.3119-1-lecopzer.chen@mediatek.com
Link: https://lore.kernel.org/r/20210112221855.10666-1-will@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
1 parent df06824
Raw File
pkcs7.h
/* SPDX-License-Identifier: GPL-2.0-or-later */
/* PKCS#7 crypto data parser
 *
 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#ifndef _CRYPTO_PKCS7_H
#define _CRYPTO_PKCS7_H

#include <linux/verification.h>
#include <linux/hash_info.h>
#include <crypto/public_key.h>

struct key;
struct pkcs7_message;

/*
 * pkcs7_parser.c
 */
extern struct pkcs7_message *pkcs7_parse_message(const void *data,
						 size_t datalen);
extern void pkcs7_free_message(struct pkcs7_message *pkcs7);

extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
				  const void **_data, size_t *_datalen,
				  size_t *_headerlen);

/*
 * pkcs7_trust.c
 */
extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
				struct key *trust_keyring);

/*
 * pkcs7_verify.c
 */
extern int pkcs7_verify(struct pkcs7_message *pkcs7,
			enum key_being_used_for usage);

extern int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7,
				      const void *data, size_t datalen);

extern int pkcs7_get_digest(struct pkcs7_message *pkcs7, const u8 **buf,
			    u32 *len, enum hash_algo *hash_algo);

#endif /* _CRYPTO_PKCS7_H */
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