4.18-stable review patch. If anyone has any objections, please let me know.
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From: Christophe Leroy christophe.leroy@c-s.fr
[ Upstream commit daf00ae71dad8aa05965713c62558aeebf2df48e ]
commit b96672dd840f ("powerpc: Machine check interrupt is a non- maskable interrupt") added a call to nmi_enter() at the beginning of machine check restart exception handler. Due to that, in_interrupt() always returns true regardless of the state before entering the exception, and die() panics even when the system was not already in interrupt.
This patch calls nmi_exit() before calling die() in order to restore the interrupt state we had before calling nmi_enter()
Fixes: b96672dd840f ("powerpc: Machine check interrupt is a non-maskable interrupt") Signed-off-by: Christophe Leroy christophe.leroy@c-s.fr Reviewed-by: Nicholas Piggin npiggin@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/kernel/traps.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
--- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -736,12 +736,17 @@ void machine_check_exception(struct pt_r if (check_io_access(regs)) goto bail;
- die("Machine check", regs, SIGBUS); - /* Must die if the interrupt is not recoverable */ if (!(regs->msr & MSR_RI)) nmi_panic(regs, "Unrecoverable Machine check");
+ if (!nested) + nmi_exit(); + + die("Machine check", regs, SIGBUS); + + return; + bail: if (!nested) nmi_exit();