1. 29 Aug, 2019 27 commits
  2. 28 Aug, 2019 12 commits
  3. 27 Aug, 2019 1 commit
    • Christopher M. Riedl's avatar
      powerpc/spinlocks: Fix oops in __spin_yield() on bare metal · 405efc59
      Christopher M. Riedl authored
      Booting w/ppc64le_defconfig + CONFIG_PREEMPT on bare metal results in
      the oops below due to calling into __spin_yield() when not running in
      an SPLPAR, which means lppaca pointers are NULL.
      
      We fixed a similar case previously in commit a6201da3 ("powerpc:
      Fix oops due to bad access of lppaca on bare metal"), by adding SPLPAR
      checks in lppaca_shared_proc(). However when PREEMPT is enabled we can
      call __spin_yield() directly from arch_spin_yield().
      
      To fix it add spin_yield() and rw_yield() which check that
      shared-processor LPAR is enabled before calling the SPLPAR-only
      implementation of each.
      
        BUG: Kernel NULL pointer dereference at 0x00000100
        Faulting instruction address: 0xc000000000097f88
        Oops: Kernel access of bad area, sig: 7 [#1]
        LE PAGE_SIZE=64K MMU=Radix MMU=Hash PREEMPT SMP NR_CPUS=2048 NUMA PowerNV
        Modules linked in:
        CPU: 0 PID: 2 Comm: kthreadd Not tainted 5.2.0-rc6-00491-g249155c2 #28
        NIP:  c000000000097f88 LR: c000000000c07a88 CTR: c00000000015ca10
        REGS: c0000000727079f0 TRAP: 0300   Not tainted  (5.2.0-rc6-00491-g249155c2)
        MSR:  9000000002009033 <SF,HV,VEC,EE,ME,IR,DR,RI,LE>  CR: 84000424  XER: 20040000
        CFAR: c000000000c07a84 DAR: 0000000000000100 DSISR: 00080000 IRQMASK: 1
        GPR00: c000000000c07a88 c000000072707c80 c000000001546300 c00000007be38a80
        GPR04: c0000000726f0c00 0000000000000002 c00000007279c980 0000000000000100
        GPR08: c000000001581b78 0000000080000001 0000000000000008 c00000007279c9b0
        GPR12: 0000000000000000 c000000001730000 c000000000142558 0000000000000000
        GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
        GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
        GPR24: c00000007be38a80 c000000000c002f4 0000000000000000 0000000000000000
        GPR28: c000000072221a00 c0000000726c2600 c00000007be38a80 c00000007be38a80
        NIP [c000000000097f88] __spin_yield+0x48/0xa0
        LR [c000000000c07a88] __raw_spin_lock+0xb8/0xc0
        Call Trace:
        [c000000072707c80] [c000000072221a00] 0xc000000072221a00 (unreliable)
        [c000000072707cb0] [c000000000bffb0c] __schedule+0xbc/0x850
        [c000000072707d70] [c000000000c002f4] schedule+0x54/0x130
        [c000000072707da0] [c0000000001427dc] kthreadd+0x28c/0x2b0
        [c000000072707e20] [c00000000000c1cc] ret_from_kernel_thread+0x5c/0x70
        Instruction dump:
        4d9e0020 552a043e 210a07ff 79080fe0 0b080000 3d020004 3908b878 794a1f24
        e8e80000 7ce7502a e8e70000 38e70100 <7ca03c2c> 70a70001 78a50020 4d820020
        ---[ end trace 474d6b2b8fc5cb7e ]---
      
      Fixes: 499dcd41 ("powerpc/64s: Allocate LPPACAs individually")
      Signed-off-by: default avatarChristopher M. Riedl <cmr@informatik.wtf>
      [mpe: Reword change log a bit]
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Link: https://lore.kernel.org/r/20190813031314.1828-4-cmr@informatik.wtf
      405efc59