CC: [email protected]
TO: Peter Zijlstra <[email protected]>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git 
perf/core
head:   a918097a296b40b4e4f7a75edf4380a293b84eb5
commit: a918097a296b40b4e4f7a75edf4380a293b84eb5 [10/10] perf: Fix task context 
PMU for Hetero
:::::: branch date: 5 hours ago
:::::: commit date: 5 hours ago
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>


cppcheck warnings: (new ones prefixed by >>)
        ^
   kernel/events/internal.h:121:2: warning: int result is returned as long 
value. If the return value is long to avoid loss of information, then you have 
loss of information. [truncLongCastReturn]
    return rb->nr_pages << (PAGE_SHIFT + page_order(rb));
    ^
   kernel/events/internal.h:126:2: warning: int result is returned as long 
value. If the return value is long to avoid loss of information, then you have 
loss of information. [truncLongCastReturn]
    return rb->aux_nr_pages << PAGE_SHIFT;
    ^

cppcheck possible warnings: (new ones prefixed by >>, may not real problems)

        ^
>> kernel/events/core.c:3831:19: warning: Uninitialized variable: cpuctx 
>> [uninitvar]
    pmu = ctx->pmu = cpuctx->ctx.pmu;
                     ^

vim +3831 kernel/events/core.c

329c0e012b99fa kernel/perf_event.c   Frederic Weisbecker 2010-01-17  3820  
e5d1367f17ba6a kernel/perf_event.c   Stephane Eranian    2011-02-14  3821  
static void perf_event_context_sched_in(struct perf_event_context *ctx,
e5d1367f17ba6a kernel/perf_event.c   Stephane Eranian    2011-02-14  3822       
                                struct task_struct *task)
235c7fc7c500e4 kernel/perf_counter.c Ingo Molnar         2008-12-21  3823  {
108b02cfce04ee kernel/perf_event.c   Peter Zijlstra      2010-09-06  3824       
struct perf_cpu_context *cpuctx;
a918097a296b40 kernel/events/core.c  Peter Zijlstra      2021-06-22  3825       
struct pmu *pmu;
a918097a296b40 kernel/events/core.c  Peter Zijlstra      2021-06-22  3826  
a918097a296b40 kernel/events/core.c  Peter Zijlstra      2021-06-22  3827       
/*
a918097a296b40 kernel/events/core.c  Peter Zijlstra      2021-06-22  3828       
 * HACK: for HETEROGENEOUS the task context might have switched to a
a918097a296b40 kernel/events/core.c  Peter Zijlstra      2021-06-22  3829       
 * different PMU, force (re)set the context,
a918097a296b40 kernel/events/core.c  Peter Zijlstra      2021-06-22  3830       
 */
a918097a296b40 kernel/events/core.c  Peter Zijlstra      2021-06-22 @3831       
pmu = ctx->pmu = cpuctx->ctx.pmu;
235c7fc7c500e4 kernel/perf_counter.c Ingo Molnar         2008-12-21  3832  
108b02cfce04ee kernel/perf_event.c   Peter Zijlstra      2010-09-06  3833       
cpuctx = __get_cpu_context(ctx);
556cccad389717 kernel/events/core.c  Kan Liang           2020-08-21  3834       
if (cpuctx->task_ctx == ctx) {
556cccad389717 kernel/events/core.c  Kan Liang           2020-08-21  3835       
        if (cpuctx->sched_cb_usage)
556cccad389717 kernel/events/core.c  Kan Liang           2020-08-21  3836       
                __perf_pmu_sched_task(cpuctx, true);
329c0e012b99fa kernel/perf_event.c   Frederic Weisbecker 2010-01-17  3837       
        return;
556cccad389717 kernel/events/core.c  Kan Liang           2020-08-21  3838       
}
329c0e012b99fa kernel/perf_event.c   Frederic Weisbecker 2010-01-17  3839  
facc43071cc0d4 kernel/events/core.c  Peter Zijlstra      2011-04-09  3840       
perf_ctx_lock(cpuctx, ctx);
fdccc3fb7a42ea kernel/events/core.c  leilei.lin          2017-08-09  3841       
/*
fdccc3fb7a42ea kernel/events/core.c  leilei.lin          2017-08-09  3842       
 * We must check ctx->nr_events while holding ctx->lock, such
fdccc3fb7a42ea kernel/events/core.c  leilei.lin          2017-08-09  3843       
 * that we serialize against perf_install_in_context().
fdccc3fb7a42ea kernel/events/core.c  leilei.lin          2017-08-09  3844       
 */
fdccc3fb7a42ea kernel/events/core.c  leilei.lin          2017-08-09  3845       
if (!ctx->nr_events)
fdccc3fb7a42ea kernel/events/core.c  leilei.lin          2017-08-09  3846       
        goto unlock;
fdccc3fb7a42ea kernel/events/core.c  leilei.lin          2017-08-09  3847  
556cccad389717 kernel/events/core.c  Kan Liang           2020-08-21  3848       
perf_pmu_disable(pmu);
329c0e012b99fa kernel/perf_event.c   Frederic Weisbecker 2010-01-17  3849       
/*
329c0e012b99fa kernel/perf_event.c   Frederic Weisbecker 2010-01-17  3850       
 * We want to keep the following priority order:
329c0e012b99fa kernel/perf_event.c   Frederic Weisbecker 2010-01-17  3851       
 * cpu pinned (that don't need to move), task pinned,
329c0e012b99fa kernel/perf_event.c   Frederic Weisbecker 2010-01-17  3852       
 * cpu flexible, task flexible.
fe45bafbd0e1b5 kernel/events/core.c  Alexander Shishkin  2017-01-19  3853       
 *
fe45bafbd0e1b5 kernel/events/core.c  Alexander Shishkin  2017-01-19  3854       
 * However, if task's ctx is not carrying any pinned
fe45bafbd0e1b5 kernel/events/core.c  Alexander Shishkin  2017-01-19  3855       
 * events, no need to flip the cpuctx's events around.
329c0e012b99fa kernel/perf_event.c   Frederic Weisbecker 2010-01-17  3856       
 */
8e1a2031e4b556 kernel/events/core.c  Alexey Budankov     2017-09-08  3857       
if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
329c0e012b99fa kernel/perf_event.c   Frederic Weisbecker 2010-01-17  3858       
        cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
63e30d3e52d4d8 kernel/events/core.c  Peter Zijlstra      2016-01-08  3859       
perf_event_sched_in(cpuctx, ctx, task);
556cccad389717 kernel/events/core.c  Kan Liang           2020-08-21  3860  
556cccad389717 kernel/events/core.c  Kan Liang           2020-08-21  3861       
if (cpuctx->sched_cb_usage && pmu->sched_task)
556cccad389717 kernel/events/core.c  Kan Liang           2020-08-21  3862       
        pmu->sched_task(cpuctx->task_ctx, true);
556cccad389717 kernel/events/core.c  Kan Liang           2020-08-21  3863  
556cccad389717 kernel/events/core.c  Kan Liang           2020-08-21  3864       
perf_pmu_enable(pmu);
fdccc3fb7a42ea kernel/events/core.c  leilei.lin          2017-08-09  3865  
fdccc3fb7a42ea kernel/events/core.c  leilei.lin          2017-08-09  3866  
unlock:
facc43071cc0d4 kernel/events/core.c  Peter Zijlstra      2011-04-09  3867       
perf_ctx_unlock(cpuctx, ctx);
235c7fc7c500e4 kernel/perf_counter.c Ingo Molnar         2008-12-21  3868  }
235c7fc7c500e4 kernel/perf_counter.c Ingo Molnar         2008-12-21  3869  

---
0-DAY CI Kernel Test Service, Intel Corporation
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