4.14-stable review patch. If anyone has any objections, please let me know.
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From: Mahesh Salgaonkar mahesh@linux.vnet.ibm.com
commit a3961f824cdbe7eb431254dc7d8f6f6767f474aa upstream.
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().
mpe: It's not safe to call trace points at this point in the kexec path, even if we could avoid the RCU checks/warnings. The only solution is to not call them.
Fixes: 0428491cba92 ("powerpc/mm: Trace tlbie(l) instructions") 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 Acked-by: Naveen N. Rao naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/powerpc/mm/hash_native_64.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
--- 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 : "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); } }