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Subject[PATCH 5.4 421/434] x86/MCE/AMD: Do not use rdmsr_safe_on_cpu() in smca_configure()
Date
From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>

commit 246ff09f89e54fdf740a8d496176c86743db3ec7 upstream.

... because interrupts are disabled that early and sending IPIs can
deadlock:

BUG: sleeping function called from invalid context at kernel/sched/completion.c:99
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/1
no locks held by swapper/1/0.
irq event stamp: 0
hardirqs last enabled at (0): [<0000000000000000>] 0x0
hardirqs last disabled at (0): [<ffffffff8106dda9>] copy_process+0x8b9/0x1ca0
softirqs last enabled at (0): [<ffffffff8106dda9>] copy_process+0x8b9/0x1ca0
softirqs last disabled at (0): [<0000000000000000>] 0x0
Preemption disabled at:
[<ffffffff8104703b>] start_secondary+0x3b/0x190
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.5.0-rc2+ #1
Hardware name: GIGABYTE MZ01-CE1-00/MZ01-CE1-00, BIOS F02 08/29/2018
Call Trace:
dump_stack
___might_sleep.cold.92
wait_for_completion
? generic_exec_single
rdmsr_safe_on_cpu
? wrmsr_on_cpus
mce_amd_feature_init
mcheck_cpu_init
identify_cpu
identify_secondary_cpu
smp_store_cpu_info
start_secondary
secondary_startup_64

The function smca_configure() is called only on the current CPU anyway,
therefore replace rdmsr_safe_on_cpu() with atomic rdmsr_safe() and avoid
the IPI.

[ bp: Update commit message. ]

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: <stable@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/157252708836.3876.4604398213417262402.stgit@buzz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/kernel/cpu/mce/amd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/cpu/mce/amd.c
+++ b/arch/x86/kernel/cpu/mce/amd.c
@@ -269,7 +269,7 @@ static void smca_configure(unsigned int
if (smca_banks[bank].hwid)
return;

- if (rdmsr_safe_on_cpu(cpu, MSR_AMD64_SMCA_MCx_IPID(bank), &low, &high)) {
+ if (rdmsr_safe(MSR_AMD64_SMCA_MCx_IPID(bank), &low, &high)) {
pr_warn("Failed to read MCA_IPID for bank %d\n", bank);
return;
}

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