The following commit has been merged into the ras/urgent branch of tip:

Commit-ID: 246ff09f89e54fdf740a8d496176c86743db3ec7 Gitweb: https://git.kernel.org/tip/246ff09f89e54fdf740a8d496176c86743db3ec7 Author: Konstantin Khlebnikov khlebnikov@yandex-team.ru AuthorDate: Thu, 31 Oct 2019 16:04:48 +03:00 Committer: Borislav Petkov bp@suse.de CommitterDate: Tue, 17 Dec 2019 09:39:33 +01:00

x86/MCE/AMD: Do not use rdmsr_safe_on_cpu() in smca_configure()

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

diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c index 5167bd2..e41e3b4 100644 --- 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 bank, unsigned int cpu) 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; }