• Anton Blanchard's avatar
    tracing/trace_stack: Fix stack trace on ppc64 · 151772db
    Anton Blanchard authored
    save_stack_trace() stores the instruction pointer, not the
    function descriptor. On ppc64 the trace stack code currently
    dereferences the instruction pointer and shows 8 bytes of
    instructions in our backtraces:
    
     # cat /sys/kernel/debug/tracing/stack_trace
            Depth    Size   Location    (26 entries)
            -----    ----   --------
      0)     5424     112   0x6000000048000004
      1)     5312     160   0x60000000ebad01b0
      2)     5152     160   0x2c23000041c20030
      3)     4992     240   0x600000007c781b79
      4)     4752     160   0xe84100284800000c
      5)     4592     192   0x600000002fa30000
      6)     4400     256   0x7f1800347b7407e0
      7)     4144     208   0xe89f0108f87f0070
      8)     3936     272   0xe84100282fa30000
    
    Since we aren't dealing with function descriptors, use %pS
    instead of %pF to fix it:
    
     # cat /sys/kernel/debug/tracing/stack_trace
            Depth    Size   Location    (26 entries)
            -----    ----   --------
      0)     5424     112   ftrace_call+0x4/0x8
      1)     5312     160   .current_io_context+0x28/0x74
      2)     5152     160   .get_io_context+0x48/0xa0
      3)     4992     240   .cfq_set_request+0x94/0x4c4
      4)     4752     160   .elv_set_request+0x60/0x84
      5)     4592     192   .get_request+0x2d4/0x468
      6)     4400     256   .get_request_wait+0x7c/0x258
      7)     4144     208   .__make_request+0x49c/0x610
      8)     3936     272   .generic_make_request+0x390/0x434
    Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
    Cc: rostedt@goodmis.org
    Cc: fweisbec@gmail.com
    LKML-Reference: <20100825013238.GE28360@kryten>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    151772db
trace_stack.c 7.67 KB