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locking/csd_lock: Change csdlock_debug from early_param to __setup

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[ Upstream commit 9c9b26b0df270d4f9246e483a44686fca951a29c ]

The csdlock_debug kernel-boot parameter is parsed by the
early_param() function csdlock_debug().  If set, csdlock_debug()
invokes static_branch_enable() to enable csd_lock_wait feature, which
triggers a panic on arm64 for kernels built with CONFIG_SPARSEMEM=y and
CONFIG_SPARSEMEM_VMEMMAP=n.

With CONFIG_SPARSEMEM_VMEMMAP=n, __nr_to_section is called in
static_key_enable() and returns NULL, resulting in a NULL dereference
because mem_section is initialized only later in sparse_init().

This is also a problem for powerpc because early_param() functions
are invoked earlier than jump_label_init(), also resulting in
static_key_enable() failures.  These failures cause the warning "static
key 'xxx' used before call to jump_label_init()".

Thus, early_param is too early for csd_lock_wait to run
static_branch_enable(), so changes it to __setup to fix these.

Fixes: 8d0968cc6b8f ("locking/csd_lock: Add boot parameter for controlling CSD lock debugging")
Cc: stable@vger.kernel.org
Reported-by: Chen jingwen <chenjingwen6@huawei.com>
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Chen Zhongjin 2022-05-10 17:46:39 +08:00 committed by Greg Kroah-Hartman
parent 96ba981f09
commit d2cbdbe22b
1 changed files with 2 additions and 2 deletions
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4
kernel/smp.c
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@ -174,9 +174,9 @@ static int __init csdlock_debug(char *str)
if (val)
static_branch_enable(&csdlock_debug_enabled);
return 0;
return 1;
}
early_param("csdlock_debug", csdlock_debug);
__setup("csdlock_debug=", csdlock_debug);
static DEFINE_PER_CPU(call_single_data_t *, cur_csd);
static DEFINE_PER_CPU(smp_call_func_t, cur_csd_func);