lkml.org 
[lkml]   [2018]   [Feb]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.14 105/159] powerpc/perf: Fix oops when grouping different pmu events
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>


    [ Upstream commit 5aa04b3eb6fca63d2e9827be656dcadc26d54e11 ]

    When user tries to group imc (In-Memory Collections) event with
    normal event, (sometime) kernel crashes with following log:

    Faulting instruction address: 0x00000000
    [link register ] c00000000010ce88 power_check_constraints+0x128/0x980
    ...
    c00000000010e238 power_pmu_event_init+0x268/0x6f0
    c0000000002dc60c perf_try_init_event+0xdc/0x1a0
    c0000000002dce88 perf_event_alloc+0x7b8/0xac0
    c0000000002e92e0 SyS_perf_event_open+0x530/0xda0
    c00000000000b004 system_call+0x38/0xe0

    'event_base' field of 'struct hw_perf_event' is used as flags for
    normal hw events and used as memory address for imc events. While
    grouping these two types of events, collect_events() tries to
    interpret imc 'event_base' as a flag, which causes a corruption
    resulting in a crash.

    Consider only those events which belongs to 'perf_hw_context' in
    collect_events().

    Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
    Reviewed-By: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
    Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
    Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    arch/powerpc/perf/core-book3s.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    --- a/arch/powerpc/perf/core-book3s.c
    +++ b/arch/powerpc/perf/core-book3s.c
    @@ -1419,7 +1419,7 @@ static int collect_events(struct perf_ev
    int n = 0;
    struct perf_event *event;

    - if (!is_software_event(group)) {
    + if (group->pmu->task_ctx_nr == perf_hw_context) {
    if (n >= max_count)
    return -1;
    ctrs[n] = group;
    @@ -1427,7 +1427,7 @@ static int collect_events(struct perf_ev
    events[n++] = group->hw.config;
    }
    list_for_each_entry(event, &group->sibling_list, group_entry) {
    - if (!is_software_event(event) &&
    + if (event->pmu->task_ctx_nr == perf_hw_context &&
    event->state != PERF_EVENT_STATE_OFF) {
    if (n >= max_count)
    return -1;

    \
     
     \ /
      Last update: 2018-02-23 20:21    [W:4.109 / U:0.012 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site