From a2e366832f3f4d5e1b47b7c7f7c41977bd5100f4 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Wed, 25 Mar 2020 20:41:44 +1000 Subject: [PATCH] powerpc/64: mark emergency stacks valid to unwind Before: WARNING: CPU: 0 PID: 494 at arch/powerpc/kernel/irq.c:343 CPU: 0 PID: 494 Comm: a Tainted: G W NIP: c00000000001ed2c LR: c000000000d13190 CTR: c00000000003f910 REGS: c0000001fffd3870 TRAP: 0700 Tainted: G W MSR: 8000000000021003 CR: 28000488 XER: 00000000 CFAR: c00000000001ec90 IRQMASK: 0 GPR00: c000000000aeb12c c0000001fffd3b00 c0000000012ba300 0000000000000000 GPR04: 0000000000000000 0000000000000000 000000010bd207c8 6b00696e74657272 GPR08: 0000000000000000 0000000000000000 0000000000000000 efbeadde00000000 GPR12: 0000000000000000 c0000000014a0000 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR24: 0000000000000000 0000000000000000 0000000000000000 000000010bd207bc GPR28: 0000000000000000 c00000000148a898 0000000000000000 c0000001ffff3f50 NIP [c00000000001ed2c] arch_local_irq_restore.part.0+0xac/0x100 LR [c000000000d13190] _raw_spin_unlock_irqrestore+0x50/0xc0 Call Trace: Instruction dump: 60000000 7d2000a6 71298000 41820068 39200002 7d210164 4bffff9c 60000000 60000000 7d2000a6 71298000 4c820020 <0fe00000> 4e800020 60000000 60000000 After: WARNING: CPU: 0 PID: 499 at arch/powerpc/kernel/irq.c:343 CPU: 0 PID: 499 Comm: a Not tainted NIP: c00000000001ed2c LR: c000000000d13210 CTR: c00000000003f980 REGS: c0000001fffd3870 TRAP: 0700 Not tainted MSR: 8000000000021003 CR: 28000488 XER: 00000000 CFAR: c00000000001ec90 IRQMASK: 0 GPR00: c000000000aeb1ac c0000001fffd3b00 c0000000012ba300 0000000000000000 GPR04: 0000000000000000 0000000000000000 00000001347607c8 6b00696e74657272 GPR08: 0000000000000000 0000000000000000 0000000000000000 efbeadde00000000 GPR12: 0000000000000000 c0000000014a0000 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR24: 0000000000000000 0000000000000000 0000000000000000 00000001347607bc GPR28: 0000000000000000 c00000000148a898 0000000000000000 c0000001ffff3f50 NIP [c00000000001ed2c] arch_local_irq_restore.part.0+0xac/0x100 LR [c000000000d13210] _raw_spin_unlock_irqrestore+0x50/0xc0 Call Trace: [c0000001fffd3b20] [c000000000aeb1ac] of_find_property+0x6c/0x90 [c0000001fffd3b70] [c000000000aeb1f0] of_get_property+0x20/0x40 [c0000001fffd3b90] [c000000000042cdc] rtas_token+0x3c/0x70 [c0000001fffd3bb0] [c0000000000dc318] fwnmi_release_errinfo+0x28/0x70 [c0000001fffd3c10] [c0000000000dcd8c] pseries_machine_check_realmode+0x1dc/0x540 [c0000001fffd3cd0] [c00000000003fe04] machine_check_early+0x54/0x70 [c0000001fffd3d00] [c000000000008384] machine_check_early_common+0x134/0x1f0 --- interrupt: 200 at 0x1347607c8 LR = 0x7fffafbd8328 Instruction dump: 60000000 7d2000a6 71298000 41820068 39200002 7d210164 4bffff9c 60000000 60000000 7d2000a6 71298000 4c820020 <0fe00000> 4e800020 60000000 60000000 Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200325104144.158362-1-npiggin@gmail.com --- arch/powerpc/kernel/process.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 110db94cdf3c..009833f928bf 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1974,6 +1974,32 @@ static inline int valid_irq_stack(unsigned long sp, struct task_struct *p, return 0; } +static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p, + unsigned long nbytes) +{ +#ifdef CONFIG_PPC64 + unsigned long stack_page; + unsigned long cpu = task_cpu(p); + + stack_page = (unsigned long)paca_ptrs[cpu]->emergency_sp - THREAD_SIZE; + if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) + return 1; + +# ifdef CONFIG_PPC_BOOK3S_64 + stack_page = (unsigned long)paca_ptrs[cpu]->nmi_emergency_sp - THREAD_SIZE; + if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) + return 1; + + stack_page = (unsigned long)paca_ptrs[cpu]->mc_emergency_sp - THREAD_SIZE; + if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) + return 1; +# endif +#endif + + return 0; +} + + int validate_sp(unsigned long sp, struct task_struct *p, unsigned long nbytes) { @@ -1985,7 +2011,10 @@ int validate_sp(unsigned long sp, struct task_struct *p, if (sp >= stack_page && sp <= stack_page + THREAD_SIZE - nbytes) return 1; - return valid_irq_stack(sp, p, nbytes); + if (valid_irq_stack(sp, p, nbytes)) + return 1; + + return valid_emergency_stack(sp, p, nbytes); } EXPORT_SYMBOL(validate_sp);