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6baea433bc
linux/arch/powerpc
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Naveen N. Rao 6baea433bc powerpc/jprobes: Disable preemption when triggered through ftrace 
KPROBES_SANITY_TEST throws the below splat when CONFIG_PREEMPT is
enabled:

  Kprobe smoke test: started
  DEBUG_LOCKS_WARN_ON(val > preempt_count())
  ------------[ cut here ]------------
  WARNING: CPU: 19 PID: 1 at kernel/sched/core.c:3094 preempt_count_sub+0xcc/0x140
  Modules linked in:
  CPU: 19 PID: 1 Comm: swapper/0 Not tainted 4.13.0-rc7-nnr+ #97
  task: c0000000fea80000 task.stack: c0000000feb00000
  NIP:  c00000000011d3dc LR: c00000000011d3d8 CTR: c000000000a090d0
  REGS: c0000000feb03400 TRAP: 0700   Not tainted  (4.13.0-rc7-nnr+)
  MSR:  8000000000021033 <SF,ME,IR,DR,RI,LE>  CR: 28000282  XER: 00000000
  CFAR: c00000000015aa18 SOFTE: 0
  <snip>
  NIP preempt_count_sub+0xcc/0x140
  LR  preempt_count_sub+0xc8/0x140
  Call Trace:
    preempt_count_sub+0xc8/0x140 (unreliable)
    kprobe_handler+0x228/0x4b0
    program_check_exception+0x58/0x3b0
    program_check_common+0x16c/0x170
    --- interrupt: 0 at kprobe_target+0x8/0x20
                     LR = init_test_probes+0x248/0x7d0
    kp+0x0/0x80 (unreliable)
    livepatch_handler+0x38/0x74
    init_kprobes+0x1d8/0x208
    do_one_initcall+0x68/0x1d0
    kernel_init_freeable+0x298/0x374
    kernel_init+0x24/0x160
    ret_from_kernel_thread+0x5c/0x70
  Instruction dump:
  419effdc 3d22001b 39299240 81290000 2f890000 409effc8 3c82ffcb 3c62ffcb
  3884bc68 3863bc18 4803d5fd 60000000 <0fe00000> 4bffffa8 60000000 60000000
  ---[ end trace 432dd46b4ce3d29f ]---
  Kprobe smoke test: passed successfully

The issue is that we aren't disabling preemption in
kprobe_ftrace_handler(). Disable it.

Fixes: ead514d5fb ("powerpc/kprobes: Add support for KPROBES_ON_FTRACE")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
[mpe: Trim oops a little for formatting]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-05 16:11:29 +11:00
..
boot powerpc: conditionally compile platform-specific serial drivers 2017-08-31 14:26:48 +10:00
configs powerpc/configs: Add Skiroot defconfig 2017-10-04 22:26:46 +11:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-05-02 15:53:46 -07:00
include powerpc/kprobes: Clean up jprobe detection in livepatch handler 2017-10-04 23:42:17 +11:00
kernel powerpc/jprobes: Disable preemption when triggered through ftrace 2017-10-05 16:11:29 +11:00
kvm kvm,powerpc: Serialize wq active checks in ops->vcpu_kick 2017-09-15 16:57:13 +02:00
lib powerpc/lib/sstep: Fix fixed-point shift instructions that set CA32 2017-10-04 11:28:04 +11:00
math-emu
mm cxl: Enable global TLBIs for cxl contexts 2017-09-28 17:09:16 +10:00
net powerpc updates for 4.14 2017-09-07 10:15:40 -07:00
oprofile powerpc/oprofile: Use setup_timer() helper 2017-10-04 11:28:01 +11:00
perf powerpc/sysrq: Fix oops whem ppmu is not registered 2017-09-20 13:30:09 +10:00
platforms powerpc/powermac: Use setup_timer() helper 2017-10-04 11:28:02 +11:00
purgatory powerpc/asm: Convert .llong directives to .8byte 2017-08-31 14:26:47 +10:00
sysdev treewide: make "nr_cpu_ids" unsigned 2017-09-08 18:26:48 -07:00
tools powerpc/64: Tool to check head sections location sanity 2017-05-30 14:59:51 +10:00
xmon powerpc/xmon: Avoid tripping SMP hardlockup watchdog 2017-10-04 11:26:23 +11:00
Kconfig powerpc updates for 4.14 2017-09-07 10:15:40 -07:00
Kconfig.debug powerpc/xmon: Enable disassembly files (compilation changes) 2017-02-15 20:02:42 +11:00
Makefile Merge branch 'fixes' into next 2017-08-23 22:20:10 +10:00
Makefile.postlink powerpc/64: Tool to check head sections location sanity 2017-05-30 14:59:51 +10:00