[PATCH 1/7] powerpc/64: mark emergency stacks valid to unwind

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From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
	Ganesh Goudar <ganeshgr@linux.ibm.com>,
	Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 1/7] powerpc/64: mark emergency stacks valid to unwind
Date: Tue, 17 Mar 2020 19:09:07 +1000	[thread overview]
Message-ID: <20200317090913.343097-2-npiggin@gmail.com> (raw)
In-Reply-To: <20200317090913.343097-1-npiggin@gmail.com>

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 <SF,ME,RI,LE>  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 <SF,ME,RI,LE>  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 <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 1dea4d280f6f..d27bf367e929 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1983,6 +1983,32 @@ 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)
 {
@@ -1994,7 +2020,10 @@ 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);
-- 
2.23.0

next prev parent reply	other threads:[~2020-03-17  9:13 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-17  9:09 [PATCH 0/7] powerpc/64: machine check and other RAS fixes Nicholas Piggin
2020-03-17  9:09 ` Nicholas Piggin [this message]
2020-03-17  9:09 ` [PATCH 2/7] powerpc/pseries/ras: avoid calling rtas_token in NMI paths Nicholas Piggin
2020-03-17  9:09 ` [PATCH 3/7] powerpc/64s: Change irq reconcile for NMIs from reusing _DAR to RESULT Nicholas Piggin
2020-03-17  9:09 ` [PATCH 4/7] powerpc/64s: machine check reconcile irq state Nicholas Piggin
2020-03-17  9:09 ` [PATCH 5/7] powerpc/pseries/ras: FWNMI_VALID off by one Nicholas Piggin
2020-03-17  9:09 ` [PATCH 6/7] powerpc/pseries/ras: fwnmi avoid modifying r3 in error case Nicholas Piggin
2020-03-17  9:09 ` [PATCH 7/7] powerpc/pseries/ras: fwnmi sreset should not interlock Nicholas Piggin

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