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| author | Michael Ellerman <mpe@ellerman.id.au> | 2018-11-01 16:21:05 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-11-12 13:22:10 +1100 |
| commit | c8b00bb742dd036388f37d019dbb9db177f3e66c (patch) | |
| tree | 09e7de4b0d6447d9bba8adb69f7f8b3b9b44a023 | |
| parent | 28c5bcf74fa07c25d5bd118d1271920f51ce2a98 (diff) | |
| download | linux-c8b00bb742dd036388f37d019dbb9db177f3e66c.tar.gz | |
powerpc/mm/64s: Fix preempt warning in slb_allocate_kernel()
With preempt enabled we see warnings in do_slb_fault():
BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u33:0/98
futex hash table entries: 4096 (order: 3, 524288 bytes)
caller is do_slb_fault+0x204/0x230
CPU: 5 PID: 98 Comm: kworker/u33:0 Not tainted 4.19.0-rc3-gcc-7.3.1-00022-g1936f094e164 #138
Call Trace:
dump_stack+0xb4/0x104 (unreliable)
check_preemption_disabled+0x148/0x150
do_slb_fault+0x204/0x230
data_access_slb_common+0x138/0x180
This is caused by the get_paca() in slb_allocate_kernel(), which
includes a call to debug_smp_processor_id().
slb_allocate_kernel() can only be called from do_slb_fault(), and in
that path interrupts are hard disabled and so we can't be preempted,
but we can't update the preempt flags (in thread_info) because that
could cause an SLB fault.
So just use local_paca which is safe and doesn't cause the warning.
Fixes: 48e7b7695745 ("powerpc/64s/hash: Convert SLB miss handlers to C")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| -rw-r--r-- | arch/powerpc/mm/slb.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c index b663a36f9ada..bc3914d54e26 100644 --- a/arch/powerpc/mm/slb.c +++ b/arch/powerpc/mm/slb.c @@ -708,7 +708,7 @@ static long slb_allocate_kernel(unsigned long ea, unsigned long id) return -EFAULT; if (ea < H_VMALLOC_END) - flags = get_paca()->vmalloc_sllp; + flags = local_paca->vmalloc_sllp; else flags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_io_psize].sllp; } else { |