From: Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>
To: linuxppc-dev <linuxppc-dev@ozlabs.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Balbir Singh <bsingharora@gmail.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Subject: [PATCH] powernv: Avoid calling trace tlbie in kexec path.
Date: Wed, 22 Nov 2017 23:02:07 +0530 [thread overview]
Message-ID: <151137178794.14123.18003389448303728066.stgit@jupiter.in.ibm.com> (raw)
From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Rebooting into a new kernel with kexec fails in trace_tlbie() which is
called from native_hpte_clear(). This happens if the running kernel has
CONFIG_LOCKDEP enabled. With lockdep enabled, the tracepoints always
execute few RCU checks regardless of whether tracing is on or off.
We are already in the last phase of kexec sequence in real mode with
HILE_BE set. At this point the RCU check ends up in RCU_LOCKDEP_WARN and
causes kexec to fail.
Fix this by not calling trace_tlbie() from native_hpte_clear().
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/mm/hash_native_64.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/mm/hash_native_64.c b/arch/powerpc/mm/hash_native_64.c
index 3848af1..640cf56 100644
--- a/arch/powerpc/mm/hash_native_64.c
+++ b/arch/powerpc/mm/hash_native_64.c
@@ -47,7 +47,8 @@
DEFINE_RAW_SPINLOCK(native_tlbie_lock);
-static inline void __tlbie(unsigned long vpn, int psize, int apsize, int ssize)
+static inline unsigned long ___tlbie(unsigned long vpn, int psize,
+ int apsize, int ssize)
{
unsigned long va;
unsigned int penc;
@@ -100,7 +101,15 @@ static inline void __tlbie(unsigned long vpn, int psize, int apsize, int ssize)
: "memory");
break;
}
- trace_tlbie(0, 0, va, 0, 0, 0, 0);
+ return va;
+}
+
+static inline void __tlbie(unsigned long vpn, int psize, int apsize, int ssize)
+{
+ unsigned long rb;
+
+ rb = ___tlbie(vpn, psize, apsize, ssize);
+ trace_tlbie(0, 0, rb, 0, 0, 0, 0);
}
static inline void __tlbiel(unsigned long vpn, int psize, int apsize, int ssize)
@@ -652,7 +661,7 @@ static void native_hpte_clear(void)
if (hpte_v & HPTE_V_VALID) {
hpte_decode(hptep, slot, &psize, &apsize, &ssize, &vpn);
hptep->v = 0;
- __tlbie(vpn, psize, apsize, ssize);
+ ___tlbie(vpn, psize, apsize, ssize);
}
}
next reply other threads:[~2017-11-22 17:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-22 17:32 Mahesh J Salgaonkar [this message]
2017-11-22 19:07 ` [PATCH] powernv: Avoid calling trace tlbie in kexec path Naveen N. Rao
2017-11-23 9:38 ` Mahesh Jagannath Salgaonkar
2017-11-23 10:02 ` Naveen N. Rao
2017-11-22 22:56 ` Balbir Singh
2017-11-23 11:18 ` Mahesh Jagannath Salgaonkar
2017-11-23 12:15 ` Michael Ellerman
2017-11-23 13:11 ` Naveen N. Rao
2017-11-24 4:13 ` Balbir Singh
2017-11-24 6:10 ` Michael Ellerman
2017-11-24 6:10 ` Michael Ellerman
2017-11-24 9:46 ` Michael Ellerman
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